A method and system for testing the torsional strength of a drive shaft

Abstract

This application belongs to the field of automotive component testing technology and discloses a method and system for testing the torsional strength of a drive shaft. The method includes: acquiring test task data, specimen structure data, assembly relationship data, and calibration data; establishing target circumferential phase coordinates and accompanying phase coordinates; performing initial phase low-damage scanning and response drift correction; determining the refinement interval based on the phase response and performing a refinement scan; calculating the phase unfavorable index; performing off-position reset confirmation on candidate unfavorable phases; obtaining the target unfavorable phase and its corresponding accompanying phase; performing phase verification and response verification based on the coupled phase path; and performing torsional loading to obtain the torsional strength result of the drive shaft. This application can reduce the influence of the initial clamping circumferential position on the torsional strength test results.

Description

Technical Field

[0001] This application relates to the field of automotive component testing technology, and more specifically, to a method and system for testing the torsional strength of a drive shaft. Background Technology

[0002] The drive shaft assembly is a torque transmission component in the vehicle's power transmission path, typically consisting of a fixed-end universal joint, a shaft, and a sliding-end universal joint. During vehicle steering, suspension movement, and changes in the drive shaft's mounting position, the universal joint may be in a non-zero sway angle state, and the drive shaft assembly needs to transmit drive torque in this state. Therefore, the torsional strength test of the drive shaft assembly needs to consider not only the loaded torque, sway angle, and sliding position, but also ensure that the actual load state inside the universal joint during the test can reflect the stress state that the drive shaft assembly may experience. Existing testing technologies can already perform torque tests on drive shaft assemblies under specified sway angles. For example, patent CN114659805B discloses a test method for a front transverse drive shaft assembly of an automobile, which includes tests for rotational torque, sway torque, circumferential clearance, and axial clearance, and further discloses a static torsional failure strength test; in the static torsional test, the universal joints at both ends can be set to 0° or a specified sway angle, and loaded until failure according to the torque direction and torque transmission method between the universal joints consistent with the vehicle installation.

[0003] Existing drive shaft assembly tests primarily simulate the vehicle's stress state by specifying macroscopic test conditions such as swing angle, slip position, torque direction, and loading rate. For example, CN114659805B explicitly positions the steel balls or rollers of the fixed joint in the same plane as the swing direction during the swing torque test, and specifies the universal joint swing angle and torque transmission method during the static torsional failure strength test. This demonstrates that the position of the internal load-bearing components of the universal joint relative to the swing direction is a structural positional factor that affects the test results. However, its disclosed static torsional failure test mainly increases the torque directly to drive shaft failure according to the specified swing angle and records the torque-torsion angle relationship, without considering the different initial circumferential positions of the drive shaft around its own axis as independent test states that need to be compared before destructive loading.

[0004] Therefore, when the target universal joint is at a non-zero sway angle, even if the same drive shaft assembly has the same sway angle, slip position, and torque loading direction, the circumferential positions of its internal steel balls, rollers, raceways, or three-pin supports relative to the sway angle plane may still differ, causing changes in the load-bearing units that actually participate in the main load transfer and their contact states. If the tester directly performs a static torsional failure test at a certain initial clamping circumferential position, the failure torque obtained from the test actually corresponds to that circumferential position, and not necessarily to the unfavorable load-bearing state that the drive shaft assembly may form under the current sway angle. For example, if two drive shaft assemblies with the same structure and manufacturing condition are installed on the test bench at different circumferential positions, under the same sway angle and loading conditions, one may place a local load-bearing unit in an unfavorable stress position, while the other may place it in a relatively favorable position, resulting in differences in the measured torsional strength. Therefore, the core technical problem of the existing technology is that in the torsional strength test where the original assembly relationship of the complete drive shaft assembly is maintained and the torsional strength test is at a specified non-zero swing angle, there is a lack of technical means to identify the load-bearing state corresponding to different initial circumferential positions. This leads to the possibility that the destructive torsional test may miss unfavorable load-bearing states due to different initial clamping circumferential positions, and thus the obtained torsional strength cannot accurately characterize the strength boundary of the specimen under the current installation conditions.

[0005] In view of this, this application proposes a method and system for testing the torsional strength of a drive shaft to solve the above problems. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the purpose of this application is to provide a method and system for testing the torsional strength of a drive shaft. By maintaining the original assembly relationship of the drive shaft assembly, low-damage scanning, phase response comparison, and off-position reset confirmation are performed on different circumferential phases. Strength loading is then applied at the confirmed unfavorable target phase and the corresponding coupled phase path position. This reduces the influence of the initial clamping circumferential position on the torsional strength test results and ensures that the obtained initial failure torque, ultimate torsional strength value, or verified lower limit of strength corresponds to the current target swing angle, target slip position, and confirmed load state.

[0007] This application provides the following technical solution: a method for testing the torsional strength of a drive shaft, comprising:

[0008] Acquire test task data, specimen structure data, original assembly relationship data, test system calibration data, and calibration data of similar specimens for the drive shaft assembly; establish target circumferential phase coordinates and accompanying phase coordinates based on specimen structure data, original assembly relationship data, and test system calibration data; obtain unified reference torque, upper boundary of low-damage scanning torque, identifiable phase response, and cumulative low-damage loading boundary based on calibration data of similar specimens.

[0009] The initial scanning position is obtained by distinguishing the angular distance and the number of target universal joint bearing units based on the target phase. The drive shaft assembly is installed and adjusted according to the test task data and the original assembly relationship data. The target circumferential phase and accompanying phase of each initial scanning position are collected under a unified reference torque to generate initial coupled phase path data.

[0010] Within the cumulative low-damage loading boundary, low-damage scanning is performed at each initial scanning position with the upper boundary of the low-damage scanning torque as the upper limit of loading. Torque, relative rotation angle, axial force and strain are collected. Drift correction is performed according to the reference phase response to obtain torsional compliance, axial force coupling and strain amplification and generate initial phase response data.

[0011] The phase interval to be refined is determined based on the initial phase response data and the identifiable phase response. Refined scanning positions are added to the phase interval to be refined, refined coupled phase path data is generated, and low-damage scanning is performed to generate refined phase response data.

[0012] The phase unfavorable index is obtained based on the initial phase response data and the refined phase response data. Candidate phase clusters and representative phases are obtained based on the phase unfavorable index and the identifiable amount of the phase response. The representative phases are subjected to off-position reset confirmation to obtain repeatable candidate unfavorable phases. Target unfavorable phase data and corresponding accompanying phase data are obtained from the repeatable candidate unfavorable phases.

[0013] Verify the coupling relationship between the target unfavorable phase data and the corresponding accompanying phase data based on the initial coupled phase path data, and determine the coupled phase path position. Adjust the drive shaft assembly to the coupled phase path position and perform phase verification and response verification. After the verification is passed, increase the torque. Generate the drive shaft torsional strength result based on the initial failure torque, the ultimate torsional strength value, or the verified lower limit of strength.

[0014] A drive shaft torsional strength testing system, comprising implementing the drive shaft torsional strength testing method, including:

[0015] The data acquisition module is used to acquire test task data, specimen structure data, original assembly relationship data, test system calibration data, and calibration data of similar specimens for the drive shaft assembly; it establishes the target circumferential phase coordinates and accompanying phase coordinates based on the specimen structure data, original assembly relationship data, and test system calibration data; and obtains the unified reference torque, the upper boundary of the low-damage scanning torque, the identifiable amount of phase response, and the cumulative low-damage loading boundary based on the calibration data of similar specimens.

[0016] The reset loading module is used to obtain the initial scanning position based on the target phase distinguishable angular distance and the number of target universal joint bearing units. It installs and adjusts the drive shaft assembly according to the test task data and original assembly relationship data. Under a unified reference torque, it collects the target circumferential phase and accompanying phase at each initial scanning position and generates initial coupled phase path data.

[0017] The drift correction module is used to perform low-damage scanning at each initial scanning position within the cumulative low-damage loading boundary, with the upper boundary of the low-damage scanning torque as the upper limit of the loading. It collects torque, relative rotation angle, axial force and strain, performs drift correction based on the reference phase response, obtains torsional compliance, axial force coupling and strain amplification and generates initial phase response data.

[0018] The refinement scanning module is used to determine the phase interval to be refined based on the initial phase response data and the identifiable amount of the phase response, add refinement scanning positions in the phase interval to be refined, generate refined coupled phase path data, perform low-damage scanning, and generate refined phase response data.

[0019] The reset confirmation module is used to obtain the phase unfavorable index based on the initial phase response data and the refined phase response data, obtain the candidate phase cluster and representative phase based on the phase unfavorable index and the identifiable amount of the phase response, perform off-position reset confirmation on the representative phase to obtain repeatable candidate unfavorable phases, and obtain the target unfavorable phase data and the corresponding accompanying phase data from the repeatable candidate unfavorable phases.

[0020] The torsion verification module is used to verify the coupling relationship between the target unfavorable phase data and the corresponding accompanying phase data based on the initial coupled phase path data and determine the coupled phase path position. The drive shaft assembly is adjusted to the coupled phase path position and phase verification and response verification are performed. After the verification is passed, the torque is increased, and the drive shaft torsion strength result is generated based on the initial failure torque, the ultimate torsion strength value or the verified lower limit of strength.

[0021] The technical effects and advantages of the drive shaft torsional strength test method and system disclosed in this application are as follows:

[0022] This application establishes target circumferential phase coordinates and accompanying phase coordinates while maintaining the original assembly relationship of the drive shaft assembly. It then utilizes test system calibration data and calibration data from similar specimens to define a unified reference torque, upper boundary of the low-damage scanning torque, identifiable phase response, and cumulative low-damage loading boundary. This allows different circumferential phases to obtain corresponding torsional compliance, axial force coupling, and strain response without entering the formal destructive loading stage. By performing low-damage scanning on the initial scanning position and the phase interval to be refined, the scanning results are corrected for reference phase drift, and candidate phases are determined based on the identifiable phase response. The unfavorable phase can transform the formal strength loading position from any circumferential position formed during initial clamping into a target unfavorable phase confirmed by response comparison and repositioning. Simultaneously, the assembly path of the target unfavorable phase is verified by utilizing the coupling relationship between the target circumferential phase and the accompanying phase, so that the formal strength loading corresponds to the confirmed load state of the complete drive shaft assembly. This reduces the influence of the initial clamping circumferential position on the torsional strength test results and ensures that the obtained initial failure torque, ultimate torsional strength value, or verified lower limit of strength corresponds to the actual load state under the current target swing angle, target slip position, and confirmed unfavorable circumferential phase. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of a drive shaft torsional strength test method according to this application;

[0024] Figure 2 This is a schematic diagram of the torsional strength test scenario for the drive shaft in this application;

[0025] Figure 3 This is a schematic diagram of the reset confirmation and verification torsion process in this application;

[0026] Figure 4 This is a schematic diagram of a drive shaft torsional strength testing system according to this application. Detailed Implementation

[0027] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0028] Example 1

[0029] Please see Figure 1 , Figure 2As shown, this embodiment provides a method for testing the torsional strength of a drive shaft, which is applied to a complete drive shaft assembly. The complete drive shaft assembly includes a fixed-end universal joint, a shaft, and a sliding-end universal joint. One universal joint is selected from the fixed-end universal joint and the sliding-end universal joint as the target universal joint, and the other universal joint is selected as the non-target universal joint.

[0030] The torsional strength testing device includes a fixed-end clamp, a loading-end clamp, a swing angle adjustment mechanism, a swing angle acquisition device, an axial position adjustment mechanism, a sliding position acquisition device, a circumferential phase adjustment mechanism, a torque loading mechanism, a torque acquisition device, a relative rotation angle acquisition device, an axial force acquisition device, a strain acquisition device, a target phase acquisition unit, an accompanying phase acquisition unit, a temperature acquisition device, a fixed-end clamping sliding acquisition unit, a loading-end clamping sliding acquisition unit, a clock synchronization unit, and a test control device.

[0031] The fixed end clamp and the loading end clamp are respectively connected to the two ends of the complete drive shaft assembly; the swing angle adjustment mechanism is used to adjust the swing angle of the target universal joint and the non-target universal joint; the axial position adjustment mechanism is used to adjust the sliding position of the complete drive shaft assembly; the circumferential phase adjustment mechanism is used to drive the complete drive shaft assembly to rotate in a coordinated manner around the fixed end axis and the loading end axis.

[0032] The relative rotation angle acquisition device acquires the circumferential angles of the inner shaft segments of the fixed-end clamp and the inner shaft segments of the loading-end clamp, respectively, and uses the difference between the two circumferential angles as the relative rotation angle of the complete drive shaft assembly; the fixed-end clamping sliding acquisition unit and the loading-end clamping sliding acquisition unit acquire the relative circumferential displacement between the corresponding clamp and the clamped shaft segment, respectively; the clock synchronization unit provides a unified sampling time scale to each acquisition device.

[0033] The drive shaft assembly can be a drive shaft assembly in an electric vehicle power transmission system, which is used to transmit torque between the power output mechanism on the drive motor side and the transmission mechanism on the drive wheel side; the drive shaft assembly can also be a drive shaft assembly of other vehicles with the same universal joint load-bearing structure and axial sliding structure.

[0034] The methods for obtaining original assembly relationship data include: reading the spline tooth position, axial assembly position, and assembly direction between the target universal joint, shaft, and non-target universal joint from the product assembly record; when the product assembly record does not record the spline tooth position, setting bridging assembly marks on adjacent connecting components, collecting the circumferential angle position and axial distance between the bridging assembly marks, and obtaining the original assembly relationship data; when the test piece is disassembled, restoring the spline tooth position, axial assembly position, and assembly direction based on the original assembly relationship data.

[0035] When adjusting the circumferential position of the complete drive shaft assembly, the circumferential phase of the target component of the target universal joint and the circumferential position of the selected component of the non-target universal joint change synchronously according to the original connection relationship; the circumferential phase of the target component under a unified reference torque is taken as the target circumferential phase, and the circumferential position of the selected component of the non-target universal joint under the same unified reference torque is taken as the accompanying phase; the target circumferential phase is used to determine the scanning position, and the accompanying phase is used to verify the coupling phase path corresponding to the target circumferential phase.

[0036] When sorting or interpolating adjacent phases that cross the zero phase, the phase with the smaller value and located after the zero phase is added. After completing the circumferential phase calculation, the angle normalization method described above is used to restore it.

[0037] The methods include:

[0038] Acquire test task data, specimen structure data, original assembly relationship data, test system calibration data, and calibration data of similar specimens for the drive shaft assembly; establish target circumferential phase coordinates and accompanying phase coordinates based on specimen structure data, original assembly relationship data, and test system calibration data; obtain unified reference torque, upper boundary of low-damage scanning torque, identifiable phase response, and cumulative low-damage loading boundary based on calibration data of similar specimens.

[0039] In specific implementations, methods for obtaining the unified reference torque, the upper boundary of the low-damage scanning torque, the identifiable phase response, and the cumulative low-damage loading boundary include:

[0040] The test task data is obtained by reading the drive shaft model, target universal joint position, target swing angle, target swing angle allowable deviation, target slip position, target slip position allowable deviation, torsional load direction, reference loading rate, reference unloading rate, scan loading rate, scan unloading rate, strength loading rate, product specified maximum loading torque, product judgment method, statistical confidence level, inspection efficiency, and allowable pre-scan influence from the product test specifications or design verification task book.

[0041] The permissible pre-scan effect represents the upper limit of the allowable reduction in torsional load capacity of a pre-scanned specimen relative to a control specimen that has not undergone pre-scanning after all low-damage loading has been performed before the formal strength loading. The method for obtaining the permissible pre-scan effect includes: selecting a specimen of the same type that has not undergone pre-scanning as a control group, and selecting a specimen of the same type that has undergone the maximum pre-scanning event sequence as a pre-scanning group, and performing formal torsional strength tests on both groups; comparing the difference in torsional strength results between the two groups of specimens, and taking the maximum allowable reduction in strength when the product verification requirements are met as the permissible pre-scan effect.

[0042] Product assessment methods include the initial structural failure assessment method and the ultimate torsional strength assessment method.

[0043] The statistical confidence level is used to determine the coverage factor and statistical quantile; the test power is denoted as 1-β; and the one-sided significance level is denoted as α.

[0044] If the test data lacks target swing angle, target sliding position, loading rate, judgment method, or allowable pre-scan influence, the formal test will not be executed.

[0045] The structural data of the target universal joint are obtained by reading the structural type, number of load-bearing units, position of inner raceway, position of outer raceway, position of cage window, position of three-pin support arm, position of roller, transition position of housing and transition position of adjacent shaft from product drawings, assembly records and non-destructive testing results.

[0046] The number of target universal joint bearing units is denoted as... For ball-cage universal joints, This indicates the number of steel balls involved in load transfer; for a three-pin universal joint, This indicates the number of three-pin support arms.

[0047] The center axis of the first shaft segment connected to the target universal joint is taken as the first reference axis of the target universal joint, and the center axis of the shaft segment on the other side of the target universal joint is taken as the second reference axis of the target universal joint; each reference axis is obtained by performing linear fitting through the center of no less than three outer circular sections of the corresponding shaft segment.

[0048] The center axis of the shaft segment connected to the non-target universal joint and used for accompanying phase projection is taken as the reference axis of the non-target universal joint.

[0049] For a three-pin universal joint, the center line of the three-pin support arm will be selected as the reference direction of the target component; for a ball cage universal joint, the center line of the cage window, the center line of the inner raceway, or the center line of the outer raceway will be selected as the reference direction of the target component.

[0050] A target phase identification mark is set on an external component with a fixed assembly relationship to the target component's reference direction; an accompanying phase identification mark is set on an external component with a fixed assembly relationship to a non-target universal joint selected component; when the target phase identification mark is only fixedly connected to the inner or outer raceway, the target circumferential phase represents the circumferential position of the corresponding inner or outer raceway, not the instantaneous arrangement position of the steel balls or cage; the target phase acquisition unit and the accompanying phase acquisition unit can be implemented using existing angle acquisition technologies, such as a combination of an industrial camera and a circumferential identification mark, a combination of a rotary encoder and a fixed zero-position mark, or a combination of a photoelectric angle sensor and a circumferential scale mark. Taking the industrial camera acquisition method as an example, the phase acquisition unit acquires an image containing the corresponding phase identification mark, determines the centerline direction of the phase identification mark according to the pre-calibrated correspondence between the image coordinates and the circumferential angle of the component, and converts the centerline direction into the circumferential angle of the corresponding component; the output data includes at least the acquisition time, the circumferential angle, and the acquisition validity indicator. Taking the rotary encoder method as an example, the encoder zero position and the pulse count corresponding to the current position are read, and the circumferential angle is calculated based on the number of pulses per revolution. The aforementioned phase acquisition technology can be implemented using existing technologies. The improvement focus of this application is not on the phase acquisition hardware itself, but on using the obtained target circumferential phase and accompanying phase for low-damage scanning location determination, coupling phase path confirmation, and formal intensity loading location verification.

[0051] Read the spline tooth position, axial insertion position, assembly direction, and clamping direction between the target universal joint, shaft, and non-target universal joint from the product assembly record.

[0052] When the product assembly record does not record the spline tooth position, bridging assembly marks are set on adjacent connecting components, and the circumferential angle position and axial distance between the bridging assembly marks are collected.

[0053] The original assembly relationship data is composed of spline tooth position, axial insertion position, assembly direction, clamping direction, circumferential angle position of bridging assembly mark and axial distance of bridging assembly mark.

[0054] When the test piece is disassembled, the drive shaft assembly is restored according to the original assembly relationship data. After restoration, if the circumferential angle difference of the bridging assembly mark does not exceed the expanded uncertainty of the target phase difference and the axial distance difference does not exceed the expanded uncertainty of the sliding position difference, the restoration of the original assembly relationship is confirmed to be effective.

[0055] Let the unit vector of the first reference axis of the target universal joint be denoted as... Let the unit vector of the second reference axis of the target gimbal be denoted as The unit vector of the target component's reference direction is denoted as... Target swing angle reference direction Obtained using the following formula: ;in, Indicates the vector magnitude; the projection direction of the target component. Obtained using the following formula: In the formula, This represents the normalized projection direction of the target component's reference direction within a section perpendicular to the first reference axis of the target universal joint.

[0056] Target circumferential phase Obtained using the following formula: ; Indicates will Transform to range When the projection direction of the target component coincides with the target swing angle reference direction, the corresponding target circumferential phase is defined as the target phase zero position.

[0057] If the denominator of any projection formula is not greater than the sine of the corresponding phase standard uncertainty, the current projection direction cannot be used to establish the target circular phase coordinates.

[0058] The unit vector of the non-target gimbal reference axis is denoted as... The unit vector of the reference direction of the selected component of the non-target universal joint is denoted as... .

[0059] A first fixed reference point and a second fixed reference point are set on the fixed component of the test rig. The unit vector pointing from the first fixed reference point to the second fixed reference point is used as the reference direction for fixing the test rig. .

[0060] The reference projection direction of the fixed test bench is obtained according to the following formula: ;in, This represents the normalized projection direction of the fixed test platform reference direction within a section perpendicular to the non-target universal joint reference axis.

[0061] The projection direction of the accompanying component is obtained according to the following formula: ;in, This indicates the normalized projection direction of the component's reference direction within a section perpendicular to the reference axis of the non-target universal joint.

[0062] Accompanying phase Obtained using the following formula: If the denominator of any projection formula is not greater than the sine of the standard uncertainty of the associated phase, the current projection direction cannot be used to establish the associated phase coordinates.

[0063] The test system calibration data includes measurement uncertainty data, time synchronization data, zero torque range data, loading response data, loading rate tolerance data, phase acquisition data, clamping slip tolerance data, temperature response data, and test termination boundary data.

[0064] Using traceable standard torque source, standard angle source, standard force source, standard strain source, standard temperature source, standard swing angle source, standard displacement source and standard angle turntable, five repeated calibrations were performed on torque, relative rotation angle, axial force, strain, temperature, swing angle, sliding position, target phase, accompanying phase and clamping sliding channel.

[0065] For any measurement quantity The standard uncertainty is obtained according to the following formula. : ;in, This indicates the measurement being calibrated. Indicates the calibration standard for the measured quantity The introduced standard uncertainty is obtained from the standard calibration certificate; Indicates the quantity to be measured Sample standard deviation of five repeated calibration results; Indicates the quantity to be measured The resolution corresponding to the acquisition channel.

[0066] Measurement expanded uncertainty Obtained using the following formula: ;in, This represents the coverage factor corresponding to the statistical confidence level specified in the experimental task.

[0067] The expanded uncertainty of the difference between the two measurement results is obtained by conservative superposition: ; This represents the standard uncertainty of the first measurement result; This represents the standard uncertainty of the second measurement result.

[0068] The expanded uncertainty of the corresponding difference is used as a measurable identifiable quantity. : .

[0069] The torque expanded uncertainty is obtained by calculating it part by part according to the above method for calculating expanded uncertainty. Relative rotation angle expansion uncertainty Axial force expansion uncertainty Strain expansion uncertainty Temperature expansion uncertainty Expanded uncertainty of the swing angle difference Uncertainty of slip position difference Standard uncertainty of target phase Accompanying phase standard uncertainty Target phase difference expansion uncertainty and accompanying phase difference expansion uncertainty .

[0070] The clock synchronization unit simultaneously sends five synchronization trigger signals to each acquisition device, and records the trigger time of each acquisition device.

[0071] The maximum absolute value of the difference between the trigger time of each acquisition device and the trigger time of the clock synchronization unit is added to the standard time uncertainty of the clock synchronization unit to obtain the expanded time synchronization uncertainty. .

[0072] The torsional section modulus at the minimum torsional section of the calibrated force transmission component is denoted as... The yield shear stress of the material is denoted as The yield torque of the calibrated force transmission component is obtained according to the following formula. : ;

[0073] When the material certificate provides the yield shear stress, the yield shear stress is used directly; when the material certificate only provides the tensile yield strength... At that time, the yield shear stress is obtained according to the following formula: The torsional section modulus of a solid circular cross-section is: ;in, This represents the diameter of the hollow circular cross-section; when the force transmission component is calibrated as a hollow circular cross-section, the torsional section modulus is obtained according to the following formula. : ;in, Indicates the outer diameter of the hollow circular cross-section; This indicates the minimum cross-sectional inner diameter of the hollow circular force transmission component.

[0074] The yield torque of the calibrated force transmission component is greater than the upper limit of the torque acquisition device's range, and the residual rotation angle does not exceed the upper limit of the torque acquisition device's range after three loading and unloading cycles. When this happens, the corresponding calibrated force transmission component is determined as the usable calibrated force transmission component.

[0075] Input the zero torque command in both the uninstalled test specimen state and the installed calibrated force transmission component state; collect data for three observation periods in each state, with each observation period including one hundred sampling points.

[0076] The maximum value of the absolute torque values ​​among all sampling points is compared with the torque expansion uncertainty. Add them together to obtain the zero torque allowable value. ; the interval As the zero torque allowable range.

[0077] The torque loading mechanism is input with five step torque commands using a calibrated force transmission component.

[0078] Starting from the moment the step command is issued, record the measured torque as it first enters the target torque increment / decrement range. The range, and the time required to maintain the corresponding range in the subsequent three sampling periods.

[0079] The maximum value among the five recorded times is used to expand the uncertainty with time synchronization. Add them together to obtain the response time of the loading mechanism. .

[0080] The lowest synchronous sampling frequency among the torque, relative rotation angle, axial force, and strain channels is denoted as . .

[0081] Loading rate calculation window duration Obtained using the following formula: .

[0082] Using available calibrated force transmission components respectively according to , , , and Perform five load or unload cycles; within a duration of The slope of the torque with respect to time is fitted within the moving window.

[0083] The maximum absolute value of the difference between the measured rate and the set rate under the same set rate is added to the expanded uncertainty of the loading rate to obtain the allowable deviation of the reference loading rate, the allowable deviation of the reference unloading rate, the allowable deviation of the scan loading rate, the allowable deviation of the scan unloading rate, and the allowable deviation of the intensity loading rate, respectively.

[0084] Using available calibrated force transmission components, the target torque is gradually increased from zero torque according to the minimum command resolution of the torque loading mechanism.

[0085] When the absolute value of the difference between the measured torque and the target torque at six consecutive sampling points does not exceed At that time, the current target torque is determined as the controllable torque.

[0086] Repeat the above process five times, and take the maximum value of the five initial controllable torques as the minimum controllable torque. .

[0087] The target phase identification mark and the accompanying phase identification mark were installed on the standard angle turntable, and eight standard angles were set at equal intervals within the complete circumference. At the target swing angle, the allowable swing angle boundary, and three observation distances, three phase acquisitions were performed for each standard angle.

[0088] The standard uncertainty of the target phase is obtained based on the calibration results. Accompanying phase standard uncertainty Target phase difference expansion uncertainty and accompanying phase difference expansion uncertainty .

[0089] Using the angular resolution of the target phase acquisition device as the angular distance increment, adjacent standard phase angular distances from small to large are set on the standard angle turntable, and twenty identifications are performed for each angular distance.

[0090] When the measured nearest standard phase position is the same as the actual standard phase position, and the circumferential angular distance between the measured angle and the actual standard angle is not greater than half of the corresponding standard phase angular distance, the corresponding identification is determined to be correct.

[0091] The angular resolution of the target phase acquisition device is read, and the expanded uncertainty of the target phase difference is obtained based on the repeated calibration results of the target phase. The larger of twice the expanded uncertainty of the target phase difference and twice the angular resolution is taken as the distinguishable angular distance of the target phase. The circumferential angular distance between the two target phases is not less than In this case, the two target phases are considered as distinguishable phase positions. For example, if the expanded uncertainty of the target phase difference is 0.4° and the angular resolution of the target phase acquisition device is 0.1°, then the expanded uncertainty of twice the target phase difference is 0.8°, and twice the angular resolution is 0.2°. Therefore, the distinguishable angular distance of the target phase is... Take 0.8°. When the circumferential angular distance between two target phases is not less than 0.8°, the two target phases are determined as distinguishable phase positions.

[0092] Half of the target phase-distinguishable angular distance is taken as the allowable deviation for phase positioning. : ;

[0093] Arrive at the same standard phase position from two opposite directions, and repeat three times at each of the eight standard phase positions.

[0094] Expand the uncertainty of the maximum circumferential angular distance between the measured phases corresponding to the two arrival directions and the target phase difference. Add them together to obtain the hysteresis compensation angle. .

[0095] When the circumferential phase adjustment mechanism is switched from one direction of rotation to the opposite direction, the hysteresis compensation angle is included in the circumferential phase adjustment amount after the reversal. This ensures that the circumferential phase adjustment mechanism completes the idle stroke corresponding to the transmission backlash before continuing to move towards the target circumferential phase. The hysteresis compensation angle is only used to generate the adjustment command for the circumferential phase adjustment mechanism and is not used to replace the measured circumferential phase of the target phase acquisition device. Whether the target circumferential phase has been reached is still determined based on the measured target circumferential phase obtained by the target phase acquisition device.

[0096] The fixed end fixture and the loading end fixture are connected by a calibrated force transmission component, and three loading or unloading operations are performed according to five loading or unloading rates.

[0097] The maximum absolute value of the relative circumferential displacement between the fixed-end clamp and the calibrated force transmission component is added to the expanded uncertainty of the fixed-end clamping slip difference to obtain the allowable amount of fixed-end clamping slip. .

[0098] The maximum absolute value of the relative circumferential displacement between the loading end clamp and the calibrated force transmission component is added to the expanded uncertainty of the loading end clamping slip difference to obtain the allowable loading end clamping slip. .

[0099] When the temperature acquisition device calibration certificate records the temperature sensor response time, the response time in the calibration certificate is read as the temperature sensor response time. .

[0100] If the calibration certificate does not specify the response time, the temperature sensor should be tested under conditions where the temperature difference is not less than ten times the temperature expansion uncertainty. Transfer between constant temperature environments; record the first temperature reading upon entering the target temperature range plus or minus. The range is determined, and the time required for three consecutive sampling points to remain within the corresponding range is recorded; this is repeated five times, and the maximum value among the five times is taken as the temperature sensor response time. .

[0101] Use twice the temperature sensor response time as the temperature observation window duration. : .

[0102] For each drive shaft assembly participating in calibration of similar specimens, cumulative low-damage loading verification, or formal strength testing, it should be installed in the corresponding test position before the first loading of the corresponding specimen, and the torque should be kept within the zero torque allowable range; data from two consecutive temperature observation windows should be collected according to the duration of the temperature observation window, and the average temperature and peak-to-peak temperature of the two temperature observation windows should be calculated respectively; when the difference between the average temperatures of the two temperature observation windows does not exceed the temperature expansion uncertainty... Furthermore, the peak-to-peak temperature values ​​of both observation windows do not exceed [a certain value]. At that time, the average temperature of the next temperature observation window is taken as the reference temperature of the specimen, and the reference temperature is increased or decreased by 10%. The range is used as the reference temperature range for the specimen; the reference temperature range is determined before the specimen is first loaded and is not updated during subsequent scanning and intensity loading of the specimen.

[0103] The minimum value among the following parameters—the maximum permissible torque of the testing equipment, the permissible torque of the fixed-end clamp, the permissible torque of the loading-end clamp, the upper limit of the torque acquisition device's range, and the maximum loading torque specified by the product—is taken as the torque stop boundary. The maximum permissible axial force of the test equipment, the maximum permissible axial force of the fixture, and the upper limit of the axial force acquisition device range are compared, and the minimum value among them is taken as the axial force stop boundary. Subtract the strain expansion uncertainty from the upper limit of the range of each strain channel. The result is then used as the strain stop for the corresponding strain channel. .

[0104] The same type of test piece refers to a drive shaft assembly that has the same drive shaft model, target universal joint structure, material, heat treatment state, grease type and amount, target swing angle, target sliding position, torsional load direction and fixture connection method as the formal test piece.

[0105] Calibration data for similar specimens includes low-damage scanning data, phase response calibration data, cumulative low-damage loading verification data, and failure identification calibration data.

[0106] The maximum number of phase positions that can be distinguished within a complete circle Obtained using the following formula: Number of phases required for coarse calibration Obtained using the following formula: ;when If the current phase acquisition accuracy does not meet the experimental requirements, the formal experiment will not be performed; At that time, the number of coarse calibration phases will be... Set to: Starting from the target phase zero position, according to The phase interval is set to coarsely calibrate the phase.

[0107] Magnetic particle inspection is used for ferromagnetic areas with accessible surfaces; penetrant testing is used for non-ferromagnetic areas with accessible surfaces; and industrial X-ray imaging or industrial computed tomography is used for inaccessible internal areas.

[0108] The minimum unacceptable defects specified in the product inspection specification are set on a reference specimen with the same material, surface condition, and structural thickness as the test specimen.

[0109] If the detection device detects the reference defect three times in a row, the non-destructive testing conditions are confirmed to be effective; if the internal reference defect cannot be detected three times in a row, disassembly inspection is adopted.

[0110] The same testing equipment, testing method, testing sensitivity, reference defect, observation direction and image reconstruction parameters are used in the same test series.

[0111] The larger of the reference loading rate and the scan loading rate is denoted as... ;in, This indicates the calculation rate for a fixed torque window.

[0112] Fixed torque window width Obtained using the following formula: ;Will As the moving step size of adjacent fixed torque windows.

[0113] The candidate torque is selected starting from the lowest candidate torque, with a fixed torque window width. The torque is increased incrementally, with the candidate torque not exceeding the torque stop boundary. If a new unacceptable defect is detected in any specimen of the same type at a certain candidate torque level, the previous candidate torque level is used as the candidate low-damage scanning torque. If no new unacceptable defect is detected even when the highest candidate torque that can be fully executed below the torque stop boundary is increased, the corresponding highest candidate torque is used as the candidate low-damage scanning torque. .

[0114] If a new unacceptable defect has been detected in the lowest candidate torque, the formal test will not be performed.

[0115] The torque and relative rotation angle data obtained during the contact closure calibration process are fitted according to the predetermined contact closure fitting method, and the contact closure fitting residual is obtained based on the difference between the fitted value and the corresponding measured value.

[0116] The contact closure fitting residual is compared with the allowable contact closure fitting residual; if the contact closure fitting residual does not exceed the allowable contact closure fitting residual, the current fitting result is determined as the effective contact closure fitting result, and the contact closure position and corresponding contact closure torque are determined based on the effective contact closure fitting result.

[0117] When the contact closure fitting residual exceeds the allowable amount of contact closure fitting residual, the current fitting result is not used to generate the contact closure position and contact closure torque. After unloading to the zero torque allowable range, the contact closure calibration is re-executed.

[0118] Only the contact closure torque obtained from the effective contact closure fitting results is used to determine the unified reference torque, thereby avoiding the use of calibration results with unstable contact states or excessive fitting errors for subsequent initial coupling phase path calibration and low-damage scanning.

[0119] Use a width of The movement step size is The contact closure recognition window is used to fit the linear relationship between the relative rotation angle and the torque.

[0120] The maximum value of the root mean square of the residuals fitted to the identification window in all coarse calibration phases is added to the expanded uncertainty of the relative rotation angle fitted residual to obtain the allowable amount of the contact closure fitted residual. .

[0121] Starting from the lowest controllable torque, with a fixed torque window width Candidate reference torques are set for incremental adjustments, and these candidate reference torques are lower than the candidate low-damage scanning torques. Three loading and unloading cycles are performed for each candidate reference torque. When the candidate reference torque is reached after three loading cycles, the circumferential angular distance between any two points of the target circumferential phase does not exceed the expanded uncertainty of the target phase difference, the circumferential angular distance between any two points of the accompanying phase does not exceed the expanded uncertainty of the accompanying phase difference, and the relative rotation angle change and strain change at each candidate strain measurement point after the three unloading cycles do not exceed the expanded uncertainty of the relative rotation angle difference and the expanded uncertainty of the strain difference, respectively. The smallest candidate reference torque that meets these conditions is then used as the unified reference torque. If no candidate reference torque meets the conditions, a formal phase scan is not performed. For example, if the minimum controllable torque is 20 N·m, the candidate reference torques are increased step by step according to the fixed torque window width to form a candidate set. Three loading and unloading operations are performed on each candidate reference torque. When the candidate reference torque is 80 N·m, the target circumferential phase repetition difference, the accompanying phase repetition difference, the change in relative rotation angle after unloading, and the change in strain all meet the corresponding expanded uncertainty requirements. If the lower candidate reference torque does not meet the repeatability requirements, 80 N·m is determined as the unified reference torque.

[0122] During the unified reference torque loading process, the fitting slope of the absolute strain value of each candidate strain measurement point with respect to the torque is calculated, and the points are arranged in descending order of fitting slope.

[0123] The number of strain channels that the strain acquisition device can acquire simultaneously is denoted as . Choose to sort first Candidate strain measurement points are selected as initial strain measurement points.

[0124] When the load transfer path of the same structure cannot form two adjacent strain measurement points, the non-adjacent measurement point with the smaller fitting slope is replaced by the candidate measurement point that is adjacent to the selected measurement point and has the largest fitting slope.

[0125] If a structural load transfer path cannot be formed between adjacent strain measurement points, load transfer events will not be used as failure auxiliary signals for that path.

[0126] Five uniform reference torque loading cycles were performed on three identical specimens that did not suffer structural damage.

[0127] For each loading event, the average relative rotation angle and the average strain at each strain measuring point are calculated in the zero torque observation window before loading and the zero torque observation window after unloading, respectively. The absolute value of the difference between the average relative rotation angle after unloading and the average relative rotation angle before loading is taken as the residual rotation angle, and the absolute value of the difference between the average strain after unloading and the average strain before loading is taken as the strain return to zero at the corresponding measuring point.

[0128] Linear fitting is performed on the torque-relative rotation angle data during the unified reference torque loading stage, and the fitting slope is used as the reference loading torsional compliance; the absolute value of the difference between two adjacent reference loading torsional compliances is used as the compliance change.

[0129] The duration of each zero-torque observation window is the greater of the temperature observation window duration and the loading mechanism response time, and includes at least six valid sampling points.

[0130] The maximum value of the absolute value of the residual angle after unloading is added to the expanded uncertainty of the relative angle difference to obtain the allowable residual angle. .

[0131] For three similar specimens, the maximum absolute value of the torsional compliance difference between two adjacent reference loading operations was taken as the allowable compliance variation during five uniform reference torque loading operations. .

[0132] The maximum value of the absolute value of the strain return to zero at the formal strain measurement points is added to the expanded uncertainty of the strain difference to obtain the allowable amount of strain return to zero. .

[0133] For each coarse calibration phase, three independent specimens of the same type are set up, and a complete scanning unit is performed under candidate low-damage scanning torque.

[0134] A complete scanning unit consists of the following components in sequence:

[0135] Pre-scan reference load event: Loading from zero torque allowable range to uniform reference torque and then unloading;

[0136] Scan loading events that involve loading from the zero torque allowable range to the candidate low-damage scan torque and then unloading.

[0137] The scanned reference load event is reloaded to the unified reference torque and then unloaded.

[0138] All specimens met the requirement that the residual rotation angle does not exceed The change in flexibility does not exceed The strain return to zero does not exceed If no new unacceptable defects are detected, the candidate low-damage scanning torque is determined as the upper boundary of the low-damage scanning torque. For example, in the verification process of similar specimens, the allowable residual rotation angle... The allowable variation in flexibility is 0.05°. The allowable value for strain returning to zero at the formal strain measurement point is 0.03. The value is 15με; when the candidate low-damage scanning torque is 800N·m, all three specimens meet the above boundary and there are no new unacceptable defects. Therefore, 800N·m is determined as the upper boundary of the low-damage scanning torque.

[0139] If any condition is not met, the candidate low-damage scanning torque is reduced by a fixed torque window width, and the unified reference torque and low-damage judgment boundary are reacquired.

[0140] For the The first phase The second scan and the first A fixed torque window is defined, and the number of valid sampling points within the window is denoted as... ; Statistical analysis of the first Within a fixed torque window The average torque of valid sampling points within a window Average relative rotation angle Average axial force , No. The average strain of each strain channel ; then calculate the first Torsional compliance of a fixed torque window :

[0141] ;in, Indicates the first Phase 1, Phase 2 The second scan, the first Within the fixed torque window, the first Torque at each sampling point; Indicates the first Phase 1, Phase 2 The second scan, the first Within the fixed torque window, the first The relative rotation angle of each sampling point.

[0142] Calculate the first Axial force coupling of a fixed torque window :

[0143] ;in, Indicates the first Phase 1, Phase 2 The second scan, the first Within the fixed torque window, the first Axial force at each sampling point.

[0144] Calculate the first The strain channel in the first Strain amplification within a fixed torque window : ;in, Indicates the first Phase 1, Phase 2 The second scan, the first Within the fixed torque window, the first The sampling point Strain in each strain channel;

[0145] The maximum torsional compliance of all effective fixed torque windows in a scanning unit is taken as the single torsional compliance; the maximum axial force coupling of all effective fixed torque windows is taken as the single axial force coupling; the maximum strain amplification of all effective fixed torque windows and the formal strain channel is taken as the single strain amplification; if the fixed torque window has missing data, range saturation, timescale reversal, or communication verification error, or if there are fewer than six effective sampling points, the corresponding window is determined as an invalid window.

[0146] Three independent specimens of the same type were set up at the maximum coarse calibration phases of torsional compliance, axial force coupling, and strain amplification, respectively. Each specimen underwent three scan cycles. For each response, the difference between the maximum and minimum values ​​of the three scan results for the same specimen was calculated, and the maximum value of the differences obtained from the three specimens was taken as the identifiable quantity of the corresponding phase response. Thus, the identifiable quantity of torsional compliance was obtained. Axial force coupling identifiable quantity and strain amplification identifiable quantity Phase response identifiable quantities include , and The phase response identifiable measure is used to determine whether the response difference between different scan results of the same formal specimen can be explained by repeated measurement fluctuations. For example, after repeated scans of the same response type, if the maximum difference in torsional compliance, the maximum difference in axial force coupling, and the maximum difference in strain amplification among three specimens of the same type are 0.02, 0.015, and 12με, respectively, then 0.02, 0.015, and 12με are taken as the phase response identifiable measures for the corresponding response types. When the response difference between different circumferential phases exceeds the corresponding phase response identifiable measure, it is determined that the response difference cannot be explained by repeated measurement fluctuations.

[0147] For each coarse calibration phase, three independent specimens of the same type were used. Each specimen underwent one scanning unit, and the torsional compliance, axial force coupling, and strain amplification of the three specimens were obtained respectively. The absolute value of the response difference between any two specimens in the same coarse calibration phase was calculated, and the maximum torsional compliance difference in all coarse calibration phases was taken as the coarse torsional compliance repeatability difference. The maximum axial force coupling difference is taken as the coarse axial force coupling repeatability difference. The maximum strain amplification difference is taken as the coarse strain amplification repeatability difference. .

[0148] For each coarse torsional compliance, coarse axial force coupling, and coarse strain amplification in the coarse calibration phase, coarse torsional compliance response sequence, coarse axial force coupling response sequence, and coarse strain amplification response sequence are formed according to the circumferential order of the target circumferential phase.

[0149] Based on the response differences obtained from repeated scans of the same coarse calibration phase, coarse torsional compliance repeatability differences were obtained respectively. Coarse axial force coupling repetitive difference and coarse strain amplification repeatability difference The coarse response repetition difference is used to distinguish between local response changes formed by repeated scanning fluctuations and effective local peak values ​​formed by target circumferential phase changes.

[0150] For any type of coarse phase response sequence, the position whose response value is not less than the two adjacent coarse calibration phase response values ​​on its circumference is determined as a local peak candidate position; for a local peak candidate position, the nearest local low value position is determined along the positive and negative directions on the circumference, and the reference response of the corresponding local peak is determined according to the larger of the two local low values; when the difference between the response value of the local peak candidate position and the reference response is greater than the corresponding coarse response repetition difference, the corresponding local peak candidate position is determined as a valid peak.

[0151] For torsional compliance response, half the difference between the effective peak response and the corresponding reference response is taken as the half-peak response increment, and the sum of the reference response and the half-peak response increment is taken as the half-peak response level. Adjacent coarse calibration phases that cross the half-peak response level are determined along both sides of the effective peak, and linear interpolation is performed based on the target circumferential phase of the adjacent coarse calibration phases and the coarse torsional compliance to obtain the left and right half-peak phases of the effective peak, respectively. Half the circumferential angular distance between the two half-peak phases along the direction containing the effective peak is taken as the torsional compliance peak half-width of the corresponding effective peak. .

[0152] According to the peak half-width of the torsional flexibility In the same way, repeat the differences based on the coarse axial force coupling. and coarse strain amplification repeatability difference Determine the effective peak value and corresponding peak half-width of the coarse axial force coupling. And the effective peak value and corresponding peak half-width of coarse strain amplification. .

[0153] When multiple effective peaks exist, the peak half-width of each effective peak is obtained, and the minimum value among the peak half-widths of all effective peaks for torsional compliance, axial force coupling, and strain amplification is determined as the effective peak half-width. The effective peak half-width is used to represent the effective influence range corresponding to the response peak. Specifically, the response value after subtracting the identifiable amount of the corresponding phase response from the response peak is used as the peak boundary. The positions on both sides of the peak are found where the peak first falls below the peak boundary, and the circumferential angular distance between the peak position and the two boundary positions is used as the half-widths on both sides. When the half-widths on both sides are inconsistent, the average of the two is taken as the effective peak half-width. If there are no effective peaks with response increments greater than the repeatability difference of the corresponding coarse phase response for a certain type of coarse phase response, the effective peak half-width is not determined using the corresponding type of coarse phase response. If none of the three types of coarse phase responses can form an effective peak, the current coarse phase response is insufficient to determine the initial scan position, and coarse phase calibration is re-performed.

[0154] If at least one effective peak half-width cannot be formed, double the current number of coarse calibration phases; if the increased number exceeds the maximum number of distinguishable phase positions. At that time, take the maximum number of distinguishable phase positions. ; Reset the coarse calibration phase at equal intervals according to the new number of phases and re-obtain the coarse phase response; reaching the maximum number of distinguishable phase positions. If at least one effective peak half-width cannot be formed afterward, the formal test will not be performed.

[0155] The minimum value among the effective peak half-widths of the three responses is denoted as... .

[0156] The initial number of scan phases is obtained according to the following formula: ;when At that time, formal experiments will not be conducted.

[0157] Starting from the target phase zero position, according to The interval is set to the initial target phase.

[0158] Intra-specimen pooled standard deviation of torsional compliance Obtained using the following formula: ;in, Indicates the first The average value of the torsional compliance of the calibration specimen over three cycles.

[0159] Combined standard deviation within axial force coupled specimens Combined standard deviation within strain amplification specimens Adopted and The same calculation method was used to obtain the result.

[0160] Will As the allowable error of the average torsional compliance, As the allowable error for the average value of axial force coupling, This is the allowable error for the average strain amplification value.

[0161] The degrees of freedom of student distribution are The cumulative probability is The quantiles are denoted as The corresponding values ​​are obtained from statistical distribution tables or statistical calculation programs.

[0162] Using three as the initial number of repetitions, the number of repetitions required for torsional compliance is iterated according to the following formula: ;in, Indicates the first The number of repetitions of the torsional compliance calculated by the wheel; Indicates the first The number of repetitions of the torsional compliance calculated by the wheel.

[0163] If the results are the same in two consecutive rounds, the iteration stops; if the same result is not obtained after 20 rounds of iteration, the formal experiment is not executed.

[0164] According to the number of repetitions with torsional flexibility The same calculation method was used to obtain the number of repetitions of axial force coupling. and strain amplification repetition number .

[0165] Number of scan units executed per formal scan phase choose , and The maximum value in.

[0166] The initial scan phase set is taken as the zeroth round phase set; a midpoint is set between every two adjacent circumferential phases, and the circumferential angular distance between the midpoint and the two ends of the interval is not less than 1 / 2. When the interval midpoint is added to the next refinement round.

[0167] Repeat the generation of refined phases until no intervals satisfying the conditions are found, thus obtaining the maximum pre-scan phase sequence.

[0168] The number of phases in the maximum pre-scan phase sequence is denoted as . The number of scan repetitions used to obtain the phase response for each pre-scan phase is [number], and according to the most unfavorable cumulative loading scenario, three additional scan units are included for each pre-scan phase: pre-scan reference, post-scan reference, and candidate confirmation; four additional scan units are included: pre-candidate confirmation reference, post-candidate confirmation reference, target phase verification before intensity loading, and reference phase verification before intensity loading; the maximum number of scan units is [number]. Obtained using the following formula: .

[0169] Let the initial scan phase number be denoted as... Two off-center reset path calibrations are performed at each initial scan position; therefore, the maximum number of path calibration events is denoted as [missing information]. and will This serves as the boundary for the number of path-calibrated events in the cumulative low-damage loading boundary.

[0170] Five specimens of the same type that did not undergo pre-scanning were selected for destructive torsion tests, and the sample standard deviation of the torsional bearing capacity results was obtained. .

[0171] The cumulative probability of the standard normal distribution is... The quantiles are denoted as The corresponding values ​​are obtained from the standard normal distribution table or statistical calculation program.

[0172] The torsional load results in the cumulative impact verification were obtained using the product determination method determined by the test task data. When the product determination method was the initial structural failure determination method, the torsional load result was the initial failure torque. When the product determination method was the ultimate torsional strength determination method, the torsional load result was the ultimate torsional strength value. The pre-scan group and the control group used the same product determination method.

[0173] Number of specimens per group in cumulative impact verification Obtained using the following formula: ;set up Pre-scanned specimens and The test specimens were matched one by one with the control specimens.

[0174] The pre-scan specimens undergo the maximum pre-scan event sequence; the control specimens are mounted in the same manner and for the same total duration as the paired pre-scan specimens; both the pre-scan specimens and the corresponding control specimens are tested within their respective reference temperature ranges, and the difference between the average initial temperatures of the two specimens does not exceed the temperature expansion uncertainty. .

[0175] After the two sets of specimens completed the corresponding process, a destructive torsion test was performed according to the same swing angle, slip position, strength loading rate and judgment method.

[0176] The average torsional bearing capacity of the control group is denoted as . The average value of the torsional bearing results of the pre-scan group is denoted as The standard deviation of the control group sample is denoted as The standard deviation of the pre-scanned group samples is denoted as .

[0177] Welch's Degree of Freedom Obtained using the following formula: The upper limit of one-sided confidence for the reduction in load capacity caused by pre-scanning. Obtained using the following formula: ;when At that time, it was confirmed that the maximum pre-scan event sequence met the cumulative low damage requirement.

[0178] Record the highest temperature of all path calibration events during the cumulative impact verification, and use the maximum value as the path calibration temperature boundary. Record the highest temperature of all scanned units during the cumulative impact verification, and use the maximum value among all the highest temperatures of the scanned units as the scan temperature boundary. Record the time required for the temperature to return to the corresponding specimen reference temperature range and remain within the range for two consecutive temperature observation windows after each loading event on the cumulative impact verification specimen; and combine the maximum value of all recovery times with... Add them together to obtain the temperature recovery time boundary. .

[0179] Define the boundary of the number of events in the path. Scanning unit number boundary Path calibration temperature boundary Scanning temperature boundary and temperature recovery time boundary This constitutes a cumulative low-damage loading boundary.

[0180] From the upper boundary of low-damage scanning torque Begin with a fixed torque window width. The calibration torque is increased incrementally; three independent test pieces of the same type are set for each calibration torque level and each coarse calibration phase.

[0181] When any new unacceptable defect is detected in any specimen, the previous stage calibration torque is used as the non-destructive high-load calibration torque. .

[0182] At each coarse calibration phase, under the uniform reference torque To achieve non-destructive high-load calibration torque Three equally spaced torque positions are set between them.

[0183] Apply amplitude at each torque position The load reduction disturbance is carried out for three consecutive sampling cycles, and then the torque is restored to the level before the disturbance.

[0184] Relative angle change rate identifiable quantity Obtained using the following formula: ;in, This represents the expanded uncertainty of the difference between two adjacent relative rotation angle measurements; Indicates the sampling period between adjacent sampling points; records the torque increase or decrease before re-entering the disturbance, based on the measured torque. The range is maintained for the time required for three consecutive sampling periods; the relative angle change rate is recorded, and the rate of change before re-entering the disturbance is added or subtracted. The range and the time required to maintain it for three consecutive sampling periods.

[0185] The total torque recovery time, relative angle change rate recovery time, and loading mechanism response time were included. The maximum value in and Add them together to obtain the recovery observation time. .

[0186] Using recoverable disturbance data from all coarsely calibrated phases, the difference between the torque before the disturbance and the minimum torque within the subsequent recovery observation period is calculated. The maximum value among all differences is added to the expanded uncertainty of the torque difference to obtain the torque reduction determination value. .

[0187] Calculate the difference between the maximum relative angle during the recovery observation period and the relative angle before the disturbance; add the maximum value of all differences to the expanded uncertainty of the relative angle difference to obtain the determination of the angle increase. .

[0188] Loading mechanism response time The larger of the six synchronous sampling periods is used as the strain comparison window duration; the strain comparison window moves according to one synchronous sampling period; for two adjacent strain comparison windows of the same formal strain measurement point, the average value of the effective strain sampling values ​​within the window is calculated respectively; the average strain of the previous window minus the average strain of the next window is the strain reduction, and the average strain of the next window minus the average strain of the previous window is the strain increase; thus, a positive strain reduction indicates a decrease in the load response of the corresponding measurement point, and a positive strain increase indicates an increase in the load response of the corresponding measurement point.

[0189] Destructive loading was performed on independent specimens of the same type at the maximum coarse calibration phases of the three phase responses. Damage locations were determined through fixed non-destructive testing or disassembly inspection. For formal strain measurement points adjacent to the damage location, a set of adjacent strain comparison windows with the largest strain reduction was determined, and the midpoint of the latter strain comparison window was taken as the strain drop response time. For formal strain measurement points adjacent to the damage location, a set of adjacent strain comparison windows with the largest strain increase was determined, and the midpoint of the latter strain comparison window was taken as the strain increase response time. The difference between the earliest and latest times among the local peak torque time, strain drop response time, and strain increase response time was calculated, and the maximum value of the time differences obtained from all destructive calibration tests was used as the time-synchronous expanded uncertainty. Add them together to obtain the duration associated with the failure event. .

[0190] In the non-destructive high-load data of all coarse-calibrated phases, the strain reduction at each formal strain measurement point is calculated according to the strain comparison window described above. The maximum value of all strain reductions is added to the expanded uncertainty of the strain difference to obtain the strain drop determination value. .

[0191] For adjacent formal strain measurement points, the strain increase is calculated according to the strain comparison window described above; the maximum strain increase is selected within the failure event association time, and the maximum value among all the maximum values ​​obtained from the non-destructive high-load tests is added to the expanded uncertainty of the strain difference to obtain the load transfer judgment value. .

[0192] Record the drive shaft model, target universal joint structure, material, heat treatment state, grease type and amount, target swing angle, target sliding position, torsional load direction, five loading or unloading rates, event start temperature, fixture structure, phase identification mark, phase observation distance and acquisition channel configuration used for system calibration and calibration of similar test pieces.

[0193] The formal test specimen and the calibration test specimen of the same type should be consistent in terms of drive shaft model, target universal joint structure, material, heat treatment state, grease type, nominal grease filling amount, torsional load direction, fixture structure, phase identification mark, and phase observation position. The target swing angle and target slip position of the formal test specimen should be within the allowable range specified in the test task, the event start temperature should be within the temperature range covered by the calibration test, and the difference between each loading or unloading rate and the corresponding calibration rate should not exceed the allowable deviation of the corresponding rate. If any condition is not met, the calibration data of the same type of test specimen should not be used.

[0194] If any condition is not met, the corresponding calibration is re-executed, and the uncalibrated interval interpolation results are not used.

[0195] Using the unit vector pointing from the fixed end to the loading end of the first reference axis of the target universal joint as the axis, the specified positive direction of the target circumferential phase is determined according to the right-hand rule; the initial scan, refined scan, repositioning and candidate phase confirmation in the same test series all use this specified positive direction of the circumferential to reach the target phase.

[0196] The initial scanning position is obtained by distinguishing the angular distance and the number of target universal joint bearing units based on the target phase. The drive shaft assembly is installed and adjusted according to the test task data and the original assembly relationship data. The target circumferential phase and accompanying phase of each initial scanning position are collected under a unified reference torque to generate the initial coupling phase path data.

[0197] In a specific implementation, the method for generating initial coupled phase path data and determining the initial scan position includes:

[0198] Install and adjust the drive shaft assembly based on the test task data, collect the initial target circumferential phase and accompanying phase under a unified reference torque, generate the initial coupled phase path data, and determine the initial scanning position accordingly.

[0199] Install the drive shaft assembly onto the fixed end fixture and the loading end fixture according to the original assembly relationship data.

[0200] Adjust the target universal joint to the target swing angle so that the difference between the measured target universal joint swing angle and the target swing angle specified in the test task does not exceed the allowable deviation of the target swing angle.

[0201] Adjust the non-target universal joint to zero swing angle, ensuring that the measured swing angle of the non-target universal joint does not exceed the expanded uncertainty of the swing angle difference. .

[0202] Adjust the drive shaft assembly to the target sliding position, ensuring that the difference between the measured sliding position and the target sliding position specified in the test task does not exceed the allowable deviation of the sliding position; when the circumferential phase adjustment direction changes relative to the previous adjustment process, perform reversal backlash compensation according to the hysteresis compensation angle, and then reach the target sliding position along the specified circumferential direction, and determine the actual reached position based on the measured phase of the target phase acquisition device and the accompanying phase acquisition device.

[0203] Phase scanning will not be performed if the above three position conditions cannot be met simultaneously.

[0204] The initial scan position starts at the target phase zero position and the interval is... set up.

[0205] Perform off-center reset path calibration twice for each initial scan position.

[0206] angular distance Obtained using the following formula: ;

[0207] Before each path calibration, rotate the drive shaft assembly until the circumferential angular distance between it and the initial phase to be calibrated is not less than [value missing]. Position; unload to the zero torque allowable range; then return to the initial phase to be calibrated along the specified positive circumference.

[0208] Load to a uniform reference torque according to the reference loading rate. Simultaneously acquire the target circumferential phase and accompanying phase, and then unload to the zero torque allowable range according to the reference unloading rate.

[0209] The first The target circumferential phases obtained from the initial scan positions and two path calibrations are denoted as follows: and The two accompanying phases are denoted as follows: and .

[0210] when , And the distance between the two inscribed angles is less than At that time, the circumferential average was used to obtain the first... Initial target circular phase and the An initial accompanying phase ;Will As the first The coupled phase path record of each initial scan position.

[0211] The calculation method is as follows:

[0212] ; The calculation method and same.

[0213] The calculation method is as follows:

[0214] Two phases and Satisfying the distance between the inscribed angles is less than The average angle of the circle is obtained according to the following formula. : If the calculation result is less than zero, add the calculation result to the result. The distance between the two angles is not less than the inscribed angle distance. At that time, no circumferential average value is generated; The calculation method and same.

[0215] The coupling phase path records of all initial scan positions are arranged in the target circumferential phase order to generate initial coupling phase path data.

[0216] If an effective coupled phase path record cannot be formed at any initial scan position, the current specimen test shall be stopped.

[0217] After each path calibration, record the number of path calibration events, the highest temperature of the event, the amount of clamping slip at the fixed end, and the amount of clamping slip at the loading end; if any data exceeds the corresponding boundary in the cumulative low-damage loading boundary, stop the current specimen test.

[0218] Within the cumulative low-damage loading boundary, low-damage scanning is performed at each initial scanning position with the upper boundary of the low-damage scanning torque as the upper limit of the loading. Torque, relative rotation angle, axial force and strain are collected. Drift correction is performed based on the reference phase response to obtain torsional compliance, axial force coupling and strain amplification and generate initial phase response data.

[0219] In a specific implementation, the method for generating initial phase response data includes:

[0220] Within the cumulative low-damage loading boundary, a low-damage scan is performed on the initial scan position with the upper boundary of the low-damage scanning torque as the upper limit of the loading. Torque data, relative rotation angle data, axial force data and strain data are collected, and drift correction is performed according to the reference phase response to generate initial phase response data.

[0221] Use the target phase zero as the reference phase; for the first At the initial scan position, the pre-scan reference phase scan unit and the first scan are executed sequentially. The initial scan positions The scanning unit and the post-scan reference phase scanning unit together constitute the first scanning unit. One single-phase scan group.

[0222] Before each scanning unit begins, the specimen temperature is brought into the specimen reference temperature range; after the previous loading event ends, the temperature recovery time boundary is reached. If the temperature still has not entered the reference temperature range of the specimen, stop the current specimen test.

[0223] When the reference loading event before scanning reaches the unified reference torque, the target circumferential phase, accompanying phase, target gimbal swing angle, non-target gimbal swing angle, and slip position are collected.

[0224] When the circumferential angular distance between the target circumferential phase and the current coupled phase path record does not exceed The circumferential angular distance between the accompanying phase and the corresponding path record does not exceed When the target swing angle, non-target swing angle, and sliding position are within their respective allowable ranges, a scan loading event is executed.

[0225] During the scan loading event, the load is applied from the zero torque allowable range to the upper boundary of the low-damage scan torque according to the scan loading rate. Then, according to the scanning unloading rate, unload to the zero torque allowable range, and simultaneously collect torque, relative rotation angle, axial force and strain of each formal strain channel.

[0226] After the scan reference loading event is completed, the residual rotation angle, compliance change, and strain return to zero are calculated.

[0227] The residual angle does not exceed The change in flexibility does not exceed The strain return to zero does not exceed The maximum temperature of the scanning unit shall not exceed The fixed end clamping slippage amount does not exceed And the amount of clamping slip at the loading end does not exceed When the time is right, the corresponding scanning unit is determined as a valid scanning unit.

[0228] For each effective scanning unit, the torsional compliance, axial force coupling, and strain amplification are obtained according to the response calculation method in step one.

[0229] Mark the response type as ,in K, A, or E can be used to represent torsional compliance, axial force coupling, or strain amplification, respectively.

[0230] The first The reference phase response at the beginning of each single-phase scan group is denoted as . The reference phase response at the end of the single-phase scan group is denoted as The corresponding collection times are recorded as follows: and ; will the first The first initial scan position The actual response obtained from the second scan is denoted as Record the corresponding collection time as According to the first At the acquisition time of the second scan, time interpolation is performed on the reference phase response before and after the scan to obtain the first... Reference phase response estimate at the next scan time : The reference phase response at the start of the first single-phase scan group. Determined as the reference response baseline; Drift correction response at the next scan time Obtained using the following formula: ; Statistics The drift-corrected average response of each phase ; respectively , and Indicates the first Torsional compliance, axial force coupling, and strain amplification of an initial phase.

[0231] The three drift-corrected average responses of all initial phases are used to form the initial phase response data.

[0232] If the difference between the reference phase response before and after scanning exceeds the identifiable amount of the corresponding phase response, the current single-phase scan group is invalid, and subsequent tests on the current specimen are stopped.

[0233] The phase interval to be refined is determined based on the initial phase response data and the identifiable phase response. Refining scan positions are added to the phase interval to be refined, refined coupled phase path data is generated, and low-damage scanning is performed to generate refined phase response data.

[0234] In a specific implementation, the method for generating refined phase response data includes:

[0235] The phase interval to be refined is determined based on the initial phase response data and the identifiable phase response. Low-damage refinement scanning is performed according to the upper boundary of the low-damage scanning torque to generate refined phase response data. The refinement scanning is performed in a progressive manner. The number of scanning positions in the first round is determined based on the width of the phase interval to be refined. After the first round of scanning is completed, if the angular distance between adjacent refinement scanning positions is still greater than the target phase distinguishable angular distance, scanning positions are added near the response peak. When the angular distance between adjacent scanning positions is no greater than the target phase distinguishable angular distance, the refinement scanning is stopped.

[0236] For torsional compliance, comparisons are made in circumferential order according to the initial target circumferential phase. When the first When the torsional compliance of the first initial phase is not less than the torsional compliance of the adjacent phases on both sides of its circumference, the first... The initial phase is determined as the location of the local maximum torsional compliance.

[0237] The difference between the local maximum torsional compliance and the maximum torsional compliance of all initial phases shall not exceed The local maximum position is determined as the position of the torsional compliance retention peak.

[0238] Following the same method as preserving the peak position of torsional compliance, the following was adopted: To determine the location of the axial force coupling peak, the following method was used. Determine the position of the strain amplification retention peak.

[0239] The interval between each retained peak position and the adjacent scanned positions on both sides of the circumference is determined as the phase interval to be refined; overlapping phase intervals to be refined are merged.

[0240] The initial scan position is taken as the zeroth refinement round; for the... To refine the cycle, set the midpoint of the interval between every two adjacent scanned positions on the circumference within the phase interval to be refined.

[0241] The circumferential angular distances between the midpoint of the interval and both ends of the interval are not less than the target phase distinguishable angular distance. When, the midpoint of the interval is taken as the first... Refine the scan position for each round.

[0242] Within the same refinement round, refinement scanning is performed in the positive direction of the specified circumference; scanning is not performed on points not located in the midpoint of the phase interval to be refined, and the order of other refinement positions is not changed.

[0243] Two off-center reset scanning units are executed for each refined scan position; after the first scan unit is completed, the drive shaft assembly is moved away from the refined scan position to a distance of not less than the circumferential angle. The scanner returns to the specified position along the positive direction of the circumference and then performs the second scanning unit.

[0244] The circumferential angular distance between the target circumferential phases obtained by the two scanning units under a uniform reference torque shall not exceed And the circumferential angular distance between the accompanying phases does not exceed At the same time, the target circumferential average phase and the accompanying circumferential average phase are calculated respectively to form a refined coupled phase path record; when the circumferential phase adjustment direction changes, hysteresis compensation is performed, and a refined coupled phase path record is formed based on the measured target circumferential phase and the accompanying phase; after forming the refined coupled phase path record for all refined scan positions, the refined coupled phase path records are arranged according to the specified circumferential order of the target circumferential phase to generate refined coupled phase path data; the refined coupled phase path data includes at least the target circumferential phase, the accompanying phase, and the refined round identifier corresponding to each refined scan position, which is used for the data assignment of subsequent scan units and the confirmation of the displacement and reset of candidate unfavorable phases.

[0245] Subsequent scanning units at the refined scanning position are assigned to the current refined scanning position only if the distance between the target circumferential phase and the accompanying phase and the refined coupled phase path record does not exceed the corresponding difference expansion uncertainty.

[0246] Following the drift correction method in step three, the torsional compliance, axial force coupling, and strain amplification of the refined scan position are obtained respectively, generating refined phase response data.

[0247] The refinement scan ends when there is no distinguishable midpoint within the phase interval to be refined in the next refinement round, or when continuing the scan would exceed the limit of the number of scan units.

[0248] The phase unfavorable index is obtained based on the initial phase response data and the refined phase response data. Candidate phase clusters and representative phases are obtained based on the phase unfavorable index and the identifiable phase response. The representative phases are subjected to off-position reset confirmation to obtain repeatable candidate unfavorable phases. The target unfavorable phase data and corresponding accompanying phase data are obtained from the repeatable candidate unfavorable phases.

[0249] In a specific implementation, the method for generating the target unfavorable phase and the corresponding accompanying phase includes:

[0250] The phase unfavorability index is calculated based on the initial phase response data and the refined phase response data. Candidate unfavorable phases are determined based on the identifiable amount of the phase response. The candidate unfavorable phases are then confirmed by displacement and reset within the cumulative low damage loading boundary, generating the target unfavorable phase and its accompanying phase.

[0251] The median torsional compliance is calculated using only the torsional compliance of the initial phase. and absolute median difference in torsional flexibility .

[0252] The absolute median difference of torsional compliance is obtained by the following formula: The median of axial force coupling was obtained using the same method. axial force coupling absolute midpoint difference Strain amplification median and strain amplification absolute median difference .

[0253] Torsional flexibility normalization scale Obtained using the following formula: According to the normalized scale of torsional flexibility The same calculation method was used to obtain the axial force coupling normalized scale. and strain amplification normalization scale For all effective scan positions consisting of the initial phase and the refined phase, the first... The unfavorable component of torsional compliance in each phase Obtained using the following formula: According to the first The unfavorable component of torsional compliance in each phase The same calculation method was used to calculate and obtain the first... Unfavorable components of axial force coupling in each phase and the Strain amplification unfavorable component in each phase ;No. Phase disadvantage index for each phase Obtained using the following formula: Phase adverse index can identify poor Obtained using the following formula: The difference between the phase misfortune index and the maximum phase misfortune index shall not exceed [a certain value]. All scanned phases are added to the candidate location set; the phase unfavorable index can be obtained by weighted summation of the normalized deviations of torsional compliance, axial force coupling, and strain amplification; the weights corresponding to each response quantity can be determined based on the discriminative power in the phase response calibration data of similar specimens, or determined according to the proportion specified in the test task.

[0254] The difference between the torsional compliance rate and the maximum torsional compliance rate shall not exceed [a certain value]. All scanned phases are added to the candidate location set; the difference between the axial force coupling and the maximum axial force coupling is not more than [a certain value]. All scanned phases are added to the candidate location set; the difference between strain amplification and maximum strain amplification is not more than [a certain value]. All scanned phases are added to the candidate position set.

[0255] Candidate positions are arranged in circumferential order according to all scanned phases; when there are no non-candidate scanned positions between candidate positions, consecutive candidate positions are divided into the same candidate phase cluster.

[0256] In circular sorting, the first and last scanned positions are adjacent to each other on the circle; when there are no non-candidate positions between the first and last candidate positions, the first and last candidate sequences are merged into the same candidate phase cluster.

[0257] Select the position with the largest phase unfavorability index from each candidate phase cluster as the representative phase.

[0258] The difference in phase disadvantage indices at multiple locations within the same candidate phase cluster does not exceed If the position cannot be distinguished, select the position with the largest strain amplification, the largest axial force coupling, and the largest torsional compliance in sequence; if the position still cannot be distinguished, select the position closest to the target phase zero position along the positive direction of the specified circumference.

[0259] For each representative phase, perform off-position reset confirmation in the order of the maximum pre-scan phase sequence.

[0260] Before confirming each representative phase, move the drive shaft assembly away from the representative phase in a direction opposite to the positive direction of the specified circumference, with a circumferential angle not less than [value missing]. The position is then switched to the specified positive circumferential direction, and the commutation backlash compensation is completed according to the hysteresis compensation angle. It then continues to return to the representative phase along the specified positive circumferential direction and performs a confirmation scan unit. The actual recovery position of the representative phase is determined according to the measured phase of the target phase acquisition device and the accompanying phase acquisition device.

[0261] Confirm that the circumferential angular distance between the target circumferential phase obtained by the scan and the original coupled phase path record does not exceed [the specified value]. Confirm that the circumferential angular distance between the accompanying phase obtained by the scan and the original coupled phase path record does not exceed [the specified value]. Furthermore, the differences between the drift-corrected torsional compliance, axial force coupling, and strain amplification and the original scan response do not exceed [a certain value]. , and When this occurs, the representative phase is determined as a repeatable candidate unfavorable phase.

[0262] When the candidate phase cluster at the location of the maximum phase unfavorable index cannot form a repeatable candidate unfavorable phase, the current specimen test is stopped.

[0263] From the repeatable candidate unfavorable phases, select the position with the largest phase unfavorability index, and take the corresponding target circumferential phase as the target unfavorable phase. The corresponding accompanying phase is taken as the accompanying phase. When the difference in the phase unfavorable index of multiple positions does not exceed the corresponding calculation uncertainty, multiple positions are taken as candidate unfavorable phases, and the target unfavorable phase is confirmed by resetting the position.

[0264] Verify the coupling relationship between the target unfavorable phase data and the corresponding accompanying phase data based on the initial coupled phase path data, and determine the coupled phase path position. Adjust the drive shaft assembly to the coupled phase path position and perform phase verification and response verification. After the verification is passed, increase the torque. Generate the drive shaft torsional strength result based on the initial failure torque, the ultimate torsional strength value, or the verified lower limit of strength.

[0265] In a specific implementation, refer to Figure 3 Methods for generating drive shaft torsional strength results include:

[0266] Based on the initial coupled phase path data, determine the location of the coupled phase path of the unfavorable phase and its companion phase. Adjust the drive shaft assembly to this location and perform phase verification and response verification. After the verification is passed, increase the torque and generate the drive shaft torsional strength result based on the initial failure torque, the ultimate torsional strength value, or the verified lower limit of strength.

[0267] From the initial coupled phase path data, calculate the circumferential angular distance between each initial target circumferential phase and the unfavorable target phase, and record the initial coupled phase path with the smallest circumferential angular distance as the path start record.

[0268] Keeping the target swing angle, non-target swing angle, target sliding position, and original assembly relationship unchanged, adjust the drive shaft assembly to the position corresponding to the path start record, and load it to a uniform reference torque according to the reference loading rate; when the circumferential angular distance between the measured target circumferential phase and the accompanying phase and the target circumferential phase and the accompanying phase in the path start record does not exceed the corresponding phase difference expansion uncertainty, confirm that the path start position has been restored to validity.

[0269] The torque is unloaded to the zero torque allowable range, causing the drive shaft assembly to rotate from the starting position of the path along the specified positive circumferential direction to the position corresponding to the unfavorable phase of the target; when the rotation direction changes before entering the specified positive circumferential direction, the reversing idle compensation is performed according to the backlash compensation angle, and after the compensation is completed, it continues to approach the position corresponding to the unfavorable phase of the target along the specified positive circumferential direction; the final state is confirmed according to the measured target circumferential phase and the accompanying phase.

[0270] If the circumferential angular distance between the current target circumferential phase and the unfavorable target phase does not exceed the expanded uncertainty of the target phase difference, and the circumferential angular distance between the current accompanying phase and the corresponding accompanying phase generated in step five does not exceed the expanded uncertainty of the accompanying phase difference, then the unfavorable target phase and the corresponding accompanying phase are confirmed to be consistent with the actual adjustment path corresponding to the initial coupled phase path data, and the position corresponding to the current target circumferential phase and the accompanying phase is determined as the coupled phase path position; if any condition is not met, intensity loading is not performed.

[0271] After the drive shaft assembly is positioned at the coupled phase path location, the torque is unloaded to the zero torque allowable range, and then an independent reference loading is performed according to the reference loading rate; and the target circumferential phase, accompanying phase, target universal joint swing angle, non-target universal joint swing angle, and slip position are synchronously acquired under a unified reference torque; when the circumferential angular distance between the measured target circumferential phase and the unfavorable target phase does not exceed the expanded uncertainty of the target phase difference. The measured circumferential angular distance between the accompanying phase and the corresponding accompanying phase does not exceed the expanded uncertainty of the accompanying phase difference. If the target universal joint angle, the non-target universal joint angle, and the sliding position are all within the corresponding allowable range, the phase verification is considered successful. If any condition is not met, the torque is unloaded to the zero torque allowable range and a repositioning is performed before the phase verification is repeated. If the re-verification still fails, the current test piece is stopped.

[0272] Before performing response verification, a reference scan unit is executed in the reference phase; in the unfavorable phase of the target, a target scan unit is executed for response verification; and then, after performing response verification, a reference scan unit is executed in the reference phase.

[0273] The verification torsional compliance, verification axial force coupling, and verification strain amplification are obtained by following the drift correction method in step three.

[0274] The difference between the reviewed torsional flexibility and the torsional flexibility at the candidate confirmation stage shall not exceed The difference between the axial force coupling in the verification stage and the axial force coupling in the candidate confirmation stage shall not exceed The difference between the strain amplification during the verification stage and the strain amplification during the candidate confirmation stage shall not exceed The response was approved upon verification.

[0275] If the difference between the reference phase response before and after the review exceeds the identifiable amount of the corresponding phase response, the response review will fail.

[0276] After both phase verification and response verification are passed, the load is applied according to the strength loading rate from the zero torque allowable range. Increase torque and simultaneously collect torque, relative rotation angle, axial force, strain, target circumferential phase, accompanying phase, temperature, and the amount of slippage between the two clamping ends.

[0277] In duration of Calculate the actual strength loading rate within the moving window; the actual strength loading rate and The difference between them continuously exceeds the allowable deviation of the strength loading rate, and the duration is not less than the response time of the loading mechanism. If necessary, the test results will be marked as invalid.

[0278] Fixed end clamping slippage exceeds Or the amount of slippage at the loading end exceeds If necessary, the test results will be marked as invalid.

[0279] If two consecutive sampling points in the torque acquisition channel or relative angle acquisition channel show missing data, range saturation, time scale reversal, or communication verification error, the test results will be marked as invalid.

[0280] If the target phase or accompanying phase acquisition channel fails after the intensity loading begins, but the torque and relative angle channels are valid, the intensity results are retained, and the phase evolution data is marked as incomplete.

[0281] The observation period will be restored. The duration of one side of the search window for local peak torque.

[0282] If the torque at a certain torque sampling point is not lower than the total effective torque values ​​within one recovery observation period before and after that sampling point, the corresponding sampling point will be determined as a candidate point for local torque peak.

[0283] Let the torque at the candidate point of the local torque peak be denoted as... Record the corresponding time as .

[0284] when The maximum torque during the subsequent recovery observation period satisfies: Furthermore, the increase in relative rotation angle within the same recovery observation period is greater than... At that time, an unrecoverable load decline candidate event is generated.

[0285] Duration of failure event association Within, the average strain reduction at a certain formal strain measurement point exceeds Furthermore, the average strain increase at adjacent formal strain measurement points exceeds [a certain threshold]. At that time, candidate events for strain load transfer are generated.

[0286] When the product is judged as a first structural failure, the torque is stopped after an irreversible load reduction candidate event or a strain load transfer candidate event occurs, and non-destructive testing is performed under fixed non-destructive testing conditions; if non-destructive testing cannot cover the internal candidate damage location, disassembly inspection is performed.

[0287] When the inspection confirms the presence of structural defects that are not permitted to be added according to the product inspection specifications, the torque at the earliest candidate event time shall be used as the initial failure torque. .

[0288] If no new unacceptable structural defect is confirmed, the current test results will be marked as invalid, and the specimen after the interruption will not be used to continue determining the initial failure torque.

[0289] When the product is judged by the ultimate torsional strength method, the loading is not stopped after a single strain drop occurs, and the torque is continued to increase until a sustained loss of load event, mechanical separation event, or test termination boundary occurs.

[0290] Under the condition that the torque loading mechanism continues to increase the target torque, the measured torque is lower than the historical maximum torque minus [a certain value] throughout the complete recovery observation period. The relative increase in angle exceeds If no new torque value higher than the original historical maximum torque is formed, a continuous load loss event is determined to have occurred.

[0291] The torque loading mechanism still outputs a loading command greater than the zero torque allowable value, the measured torque enters the zero torque allowable range, and the increase in relative angle during the recovery observation period exceeds [a certain value]. A mechanical separation event is determined when the torque returns to zero due to active unloading.

[0292] Select the maximum value from all effective torque data between the start of strength loading and the confirmation of a sustained load loss event or mechanical separation event, and determine the corresponding maximum value as the ultimate torsional strength value. .

[0293] During the strength loading process, when the measured torque reaches The measured axial force reached Or any strain channel reaches the corresponding However, if initial structural failure, loss of sustained load, or mechanical separation has not yet been confirmed, the increase of torque should be stopped, and the maximum effective torque before termination should be taken as the lower limit of the verified strength. .

[0294] When the product is determined using the initial structural failure assessment method and initial structural failure is confirmed, This is the initial failure torque result for the drive shaft assembly.

[0295] When the product is judged by the ultimate torsional strength test and it is confirmed that the continuous load has been lost or mechanical separation has occurred, As the ultimate torsional strength value of the drive shaft assembly.

[0296] When the test termination boundary is reached but the corresponding failure event is not confirmed, This serves as the verified lower limit of strength for the drive shaft assembly.

[0297] Record result type and target unfavorable phase Accompanying phase The system generates the torsional strength results of the drive shaft by taking the coupling phase path position, phase evolution data, initial failure torque, ultimate torsional strength value, verified lower limit of strength, relative rotation angle at termination, axial force at termination, maximum strain, location of maximum strain measurement point, confirmed failure location, and reason for test termination.

[0298] The final torsional strength result of the drive shaft corresponds only to the test results of the current single complete drive shaft assembly under the target swing angle, target slip position, torsional load direction, target unfavorable phase and corresponding accompanying phase specified in the test task.

[0299] When a test result is marked as invalid, the corresponding data will not be used for overall strength statistics of the same type of drive shaft, updating calibration data of the same type of test piece, or determining product qualification.

[0300] Example 2

[0301] Please see Figure 4 As shown, this embodiment provides a drive shaft torsional strength testing system, including:

[0302] The data acquisition module is used to acquire test task data, specimen structure data, original assembly relationship data, test system calibration data, and calibration data of similar specimens for the drive shaft assembly; it establishes the target circumferential phase coordinates and accompanying phase coordinates based on the specimen structure data, original assembly relationship data, and test system calibration data; and it obtains the unified reference torque, the upper boundary of the low-damage scanning torque, the identifiable amount of phase response, and the cumulative low-damage loading boundary based on the calibration data of similar specimens.

[0303] The reset loading module is used to obtain the initial scanning position based on the target phase distinguishable angular distance and the number of target universal joint bearing units. Based on the test task data and original assembly relationship data, the drive shaft assembly is installed and adjusted. Under a unified reference torque, the target circumferential phase and accompanying phase of each initial scanning position are collected to generate initial coupling phase path data.

[0304] The drift correction module is used to perform low-damage scanning at each initial scanning position within the cumulative low-damage loading boundary, with the upper boundary of the low-damage scanning torque as the upper limit of the loading. It collects torque, relative rotation angle, axial force and strain, performs drift correction based on the reference phase response, obtains torsional compliance, axial force coupling and strain amplification and generates initial phase response data.

[0305] The refinement scanning module is used to determine the phase interval to be refined based on the initial phase response data and the identifiable phase response, add refinement scanning positions in the phase interval to be refined, generate refined coupled phase path data, perform low-damage scanning, and generate refined phase response data.

[0306] The reset confirmation module is used to obtain the phase unfavorable index based on the initial phase response data and the refined phase response data, obtain the candidate phase cluster and representative phase based on the phase unfavorable index and the identifiable phase response, perform off-position reset confirmation on the representative phase to obtain repeatable candidate unfavorable phases, and obtain the target unfavorable phase data and the corresponding accompanying phase data from the repeatable candidate unfavorable phases.

[0307] The torsion verification module is used to verify the coupling relationship between the target unfavorable phase data and the corresponding accompanying phase data based on the initial coupled phase path data and determine the coupled phase path position. The drive shaft assembly is adjusted to the coupled phase path position and phase verification and response verification are performed. After the verification is passed, the torque is increased, and the drive shaft torsion strength result is generated based on the initial failure torque, the ultimate torsion strength value or the verified lower limit of strength.

[0308] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for testing the torsional strength of a drive shaft, characterized in that, include: Acquire test task data, specimen structure data, original assembly relationship data, test system calibration data, and calibration data of similar specimens for the drive shaft assembly; Based on the specimen structure data, original assembly relationship data and test system calibration data, establish the target circumferential phase coordinates and accompanying phase coordinates. Based on the calibration data of similar specimens, obtain the unified reference torque, the upper boundary of the low-damage scanning torque, the identifiable amount of phase response and the cumulative low-damage loading boundary. The initial scanning position is obtained by distinguishing the angular distance and the number of target universal joint bearing units based on the target phase. The drive shaft assembly is installed and adjusted according to the test task data and the original assembly relationship data. The target circumferential phase and accompanying phase of each initial scanning position are collected under a unified reference torque to generate initial coupled phase path data. Within the cumulative low-damage loading boundary, low-damage scanning is performed at each initial scanning position with the upper boundary of the low-damage scanning torque as the upper limit of loading. Torque, relative rotation angle, axial force and strain are collected. Drift correction is performed according to the reference phase response to obtain torsional compliance, axial force coupling and strain amplification and generate initial phase response data. The phase interval to be refined is determined based on the initial phase response data and the identifiable phase response. Refined scanning positions are added to the phase interval to be refined, refined coupled phase path data is generated, and low-damage scanning is performed to generate refined phase response data. The phase unfavorable index is obtained based on the initial phase response data and the refined phase response data. Candidate phase clusters and representative phases are obtained based on the phase unfavorable index and the identifiable amount of the phase response. The representative phases are subjected to off-position reset confirmation to obtain repeatable candidate unfavorable phases. Target unfavorable phase data and corresponding accompanying phase data are obtained from the repeatable candidate unfavorable phases. Verify the coupling relationship between the target unfavorable phase data and the corresponding accompanying phase data based on the initial coupled phase path data, and determine the coupled phase path position. Adjust the drive shaft assembly to the coupled phase path position and perform phase verification and response verification. After the verification is passed, increase the torque. Generate the drive shaft torsional strength result based on the initial failure torque, the ultimate torsional strength value, or the verified lower limit of strength.

2. The method for testing the torsional strength of a drive shaft according to claim 1, characterized in that, The method for obtaining the target circumferential phase and its accompanying phase includes: establishing the target circumferential phase coordinates by projecting the axes on both sides of the target universal joint and the reference direction of the target component; obtaining the target circumferential phase based on the directed angle between the reference direction of the target component and the target swing angle reference direction; projecting the reference direction of the selected component of the non-target universal joint and the reference direction of the fixed test platform onto a section perpendicular to the reference axis of the non-target universal joint; and obtaining the accompanying phase based on the directed angle between the two projection directions.

3. The method for testing the torsional strength of a drive shaft according to claim 1, characterized in that, The method for obtaining the unified reference torque and the upper boundary of the low-damage scanning torque includes: setting incremental candidate torques according to a fixed torque window, performing loading, unloading, and defect checks on each candidate torque and each coarse calibration phase, determining the candidate low-damage scanning torque based on the candidate torque that first appears with newly added unacceptable defects; determining the unified reference torque based on the phase repeatability and unloading recovery results in repeated reference loading, and determining the upper boundary of the low-damage scanning torque based on the residual rotation angle, compliance change, strain return to zero, and defect check results after scanning.

4. The method for testing the torsional strength of a drive shaft according to claim 1, characterized in that, The method for obtaining the initial scanning position includes: obtaining the maximum number of distinguishable phase positions within a complete circumference based on the distinguishable angular distance of the target phase; determining the number of coarse calibration phases based on the number of target universal joint bearing units; repeatedly performing low-damage scanning on each coarse calibration phase to obtain coarse torsional compliance, coarse axial force coupling, and coarse strain amplification, and obtaining the repeatability differences of coarse torsional compliance, coarse axial force coupling, and coarse strain amplification respectively. The effective peak value is determined based on the coarse phase response and the corresponding repetition difference. The effective peak half-width is obtained based on the effective peak value. At least four initial scanning positions are determined based on the effective peak half-width, and the initial scanning positions are set at equal intervals along the complete circumference. The effective peak half-width represents the circumferential angular distance between the position where the response value drops to the peak value minus the corresponding identifiable amount of the phase response. When there are positions that meet the conditions on both sides of the peak value, the average value of the distances on both sides is taken as the effective peak half-width.

5. The method for testing the torsional strength of a drive shaft according to claim 1, characterized in that, The method for obtaining initial phase response data includes: acquiring reference phase responses before and after target phase scanning, performing time interpolation on the reference phase responses before and after scanning based on the acquisition time of the target phase response to obtain an estimated reference phase response value; subtracting the estimated reference phase response value from the target phase response and adding the reference response benchmark to obtain the drift-corrected phase response.

6. The method for testing the torsional strength of a drive shaft according to claim 1, characterized in that, The method for obtaining refined phase response data includes: determining the local maximum position in the torsional compliance, axial force coupling, and strain amplification of the initial phase, respectively; determining the position where the difference between the local maximum response and the corresponding maximum response does not exceed the phase response distinguishable amount as the retained peak position; taking the circumferential adjacent intervals on both sides of the retained peak position as the phase interval to be refined, and performing low-damage refined scanning according to the refinement rounds and the specified positive circumferential direction to obtain refined phase response data; the refinement rounds are determined based on the width of the phase interval to be refined and the target phase distinguishable angular distance; when the angular distance between adjacent scan positions after a single refinement is still greater than the target phase distinguishable angular distance, the next round of refinement is continued; when the angular distance between adjacent scan positions is not greater than the target phase distinguishable angular distance, refinement is stopped.

7. The method for testing the torsional strength of a drive shaft according to claim 1, characterized in that, The method for obtaining refined coupled phase path data includes: moving the drive shaft assembly from the off-position position to the refined scanning position along a specified circumferential direction and performing a low-damage scan; moving it away from the refined scanning position again and returning along the same circumferential direction and performing a low-damage scan; comparing the target circumferential phase and the accompanying phase of the two scans under a unified reference torque; and generating refined coupled phase path data when the phase difference between the two types does not exceed the expanded uncertainty of the corresponding phase difference value.

8. The method for testing the torsional strength of a drive shaft according to claim 1, characterized in that, The method for obtaining the target unfavorable phase and its corresponding accompanying phase includes: obtaining the median, absolute median difference, and normalized scale of each response based on the torsional compliance, axial force coupling, and strain amplification of the initial phase; calculating the phase unfavorable index based on the positive deviation of the initial phase response data and refined phase response data relative to the corresponding median; determining candidate positions and forming candidate phase clusters based on the identifiable difference of the phase unfavorable index and the identifiable amount of the phase response; performing off-position reset confirmation on the representative phase of each candidate phase cluster; using the confirmed representative phase as the repeatable candidate unfavorable phase; using the target circumferential phase at the position with the largest phase unfavorable index as the target unfavorable phase; and using the corresponding accompanying phase as the accompanying phase.

9. The method for testing the torsional strength of a drive shaft according to claim 1, characterized in that, The method for verifying the cumulative low-damage loading boundary includes: The maximum pre-scan event sequence is generated based on the initial scan position, refined scan position, number of scan repetitions, reference scan, and candidate confirmation process. The maximum number of scan units and the maximum scan torque are obtained based on the maximum pre-scan event sequence. The maximum number of path calibration events is obtained based on the path calibration process of the initial scan position, and the scan temperature boundary is obtained. The maximum number of scanning units, the maximum number of path calibration events, the maximum scanning torque, and the scanning temperature boundary are compared with the corresponding cumulative low-damage loading boundary in the calibration data of the same type of specimen. If none of them exceed the corresponding cumulative low-damage loading boundary, a pre-scan is performed; if any one of them reaches the corresponding cumulative low-damage loading boundary, the addition of the corresponding pre-scan events is stopped.

10. The method for testing the torsional strength of a drive shaft according to claim 1, characterized in that, The calibration data for the same type of specimens includes failure identification calibration data. The method for obtaining the failure identification calibration data includes: performing a torsional failure calibration test on the same type of specimens, simultaneously collecting torque, relative rotation angle, and strain at formal strain measurement points, and determining the structural failure event in conjunction with the structural failure inspection results; obtaining the recovery observation time and the torque decrease and relative rotation angle increment between the local peak torque and the maximum subsequent torque within the recovery observation time based on the torque change before and after the structural failure event; and obtaining the failure event association time, the average strain decrease at formal strain measurement points, and the average strain increase at adjacent formal strain measurement points based on the strain load transfer process, thereby generating failure identification calibration data.

11. The method for testing the torsional strength of a drive shaft according to claim 1, characterized in that, The method for generating the torsional strength result of the drive shaft includes: During the strength loading process, a local peak torque is obtained. When the maximum subsequent torque within the recovery observation period after the local peak torque is lower than the local peak torque minus the torque decrease in the failure identification calibration data, and the relative angle increment within the recovery observation period is greater than the relative angle increment in the failure identification calibration data, an unrecoverable load reduction candidate event is determined. When the average strain decrease at any formal strain measurement point within the failure event association period is greater than the average strain decrease in the failure identification calibration data, and the average strain increase at adjacent formal strain measurement points is greater than the average strain increase in the failure identification calibration data, a strain load transfer candidate event is determined. When the product determination method is the initial structural failure determination method, after the formation of the candidate event of irreversible load reduction or strain load transfer, a structural inspection is performed. If it is confirmed that there is a structural defect that is not allowed to be added as specified in the product inspection specification, the torque corresponding to the earliest candidate event is determined as the initial failure torque. When the product determination method is the ultimate torsional strength determination method, the maximum effective torque between the start of strength loading and the confirmation time of the sustained load loss event or mechanical separation event is determined as the ultimate torsional strength value. When the test termination boundary is reached and no corresponding failure event is confirmed, the maximum effective torque before termination is determined as the verified lower limit of strength.

12. A drive shaft torsional strength testing system, characterized in that, A method for implementing the torsional strength test of a drive shaft according to any one of claims 1-11, comprising: The data acquisition module is used to acquire test task data, specimen structure data, original assembly relationship data, test system calibration data, and calibration data of similar specimens for the drive shaft assembly; it establishes the target circumferential phase coordinates and accompanying phase coordinates based on the specimen structure data, original assembly relationship data, and test system calibration data; and it obtains the unified reference torque, the upper boundary of the low-damage scanning torque, the identifiable amount of phase response, and the cumulative low-damage loading boundary based on the calibration data of similar specimens. The reset loading module is used to obtain the initial scanning position based on the target phase distinguishable angular distance and the number of target universal joint bearing units. It installs and adjusts the drive shaft assembly according to the test task data and original assembly relationship data. Under a unified reference torque, it collects the target circumferential phase and accompanying phase at each initial scanning position and generates initial coupled phase path data. The drift correction module is used to perform low-damage scanning at each initial scanning position within the cumulative low-damage loading boundary, with the upper boundary of the low-damage scanning torque as the upper limit of the loading. It collects torque, relative rotation angle, axial force and strain, performs drift correction based on the reference phase response, obtains torsional compliance, axial force coupling and strain amplification and generates initial phase response data. The refinement scanning module is used to determine the phase interval to be refined based on the initial phase response data and the identifiable amount of the phase response, add refinement scanning positions in the phase interval to be refined, generate refined coupled phase path data, perform low-damage scanning, and generate refined phase response data. The reset confirmation module is used to obtain the phase unfavorable index based on the initial phase response data and the refined phase response data, obtain the candidate phase cluster and representative phase based on the phase unfavorable index and the identifiable amount of the phase response, perform off-position reset confirmation on the representative phase to obtain repeatable candidate unfavorable phases, and obtain the target unfavorable phase data and the corresponding accompanying phase data from the repeatable candidate unfavorable phases. The torsion verification module is used to verify the coupling relationship between the target unfavorable phase data and the corresponding accompanying phase data based on the initial coupled phase path data and determine the coupled phase path position. The drive shaft assembly is adjusted to the coupled phase path position and phase verification and response verification are performed. After the verification is passed, the torque is increased, and the drive shaft torsion strength result is generated based on the initial failure torque, the ultimate torsion strength value or the verified lower limit of strength.

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