A clamping force control method, system, terminal and storage medium
By monitoring and dynamically correcting the clamping force in real time, and taking into account the environment and fixture status, the problem of insufficient accuracy and automation in clamping force control in existing technologies has been solved, achieving efficient, stable and safe operation of material mechanics testing.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Filing Date
- 2026-05-19
- Publication Date
- 2026-07-14
AI Technical Summary
Existing clamping force control methods suffer from insufficient accuracy and low automation, resulting in low efficiency in material mechanics testing, inaccurate clamping, and an inability to monitor clamping force changes in real time, thus affecting the accuracy and safety of test results.
By acquiring the material type of the material to be tested, the optimal clamping force and preset test height are selected, the actual clamping force is monitored in real time, and alarms are triggered and data is recorded during the tensile test, dynamically correcting the optimal clamping force; the stability of the clamping force is evaluated and alarms are triggered in combination with the ambient temperature and fixture status; the optimal clamping force is intelligently set by identifying the fixture wear state and composite material structure.
It significantly improves the accuracy of clamping force control and the safety of the testing process, avoids sample slippage or damage caused by improper clamping, improves material testing efficiency and reliability under high temperature environments, and reduces human intervention.
Smart Images
Figure CN122385334A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of mechanical testing, and in particular to a clamping force control method, system, terminal, and storage medium. Background Technology
[0002] In modern materials mechanics testing, clamping force control methods are a key technical support for improving testing efficiency and accurately matching clamping forces.
[0003] In related technologies, before tensile testing, operators need to manually set the clamping force based on experience and make manual adjustments according to the sample type and clamping degree. Furthermore, it is impossible to know the changes in clamping force in real time during the test.
[0004] Regarding the aforementioned technologies, there are issues with insufficient accuracy in setting the clamping force and limited automation when adjusting the clamping force, resulting in low efficiency in test preparation and inaccurate clamping adaptation. Summary of the Invention
[0005] To improve testing efficiency and accurately match clamping force, this application provides a clamping force control method, system, terminal, and storage medium.
[0006] In a first aspect, this application provides a clamping force control method, which adopts the following technical solution: A clamping force control method, comprising: Obtain the material type of the material to be tested; Call the optimal clamping force and preset test height corresponding to the material type in the test module; Control the crossbeam to move to the preset test height and control the clamps of the electronic universal testing machine to close, applying an initial clamping force to the material to be tested; After the initial clamping force reaches the optimal clamping force, a tensile test is performed on the material to be tested, and the crossbeam is controlled to run at a preset tensile rate. During the tensile test, the actual clamping force is monitored in real time; Determine whether the actual clamping force exceeds the clamping force threshold range; If not, then the step of monitoring the actual clamping force in real time during the tensile test is performed until the material under test breaks. If so, a test alarm command will be triggered, and the actual clamping force will be recorded; After the tensile test, the optimal clamping force is corrected based on the recorded actual clamping force.
[0007] By adopting the above technical solution, the material type of the material to be tested is obtained, the optimal clamping force and preset test height are selected, and the testing machine is controlled to accurately apply the initial clamping force. During the tensile test, the actual clamping force change is monitored in real time. If the threshold is exceeded, an alarm is triggered and data is recorded. After the test, the optimal clamping force is dynamically corrected based on feedback. This solution significantly improves the accuracy and adaptability of the optimal clamping force setting, effectively avoids sample slippage or damage caused by improper clamping, enhances the automation and intelligence level of the tensile testing process, and improves material testing efficiency.
[0008] Optionally, obtain the ambient temperature of the test environment; Determine if the ambient temperature is higher than the temperature threshold; If so, then obtain the first clamping force at the first time point and the first deformation rate of the gauge length segment of the material to be tested; The second clamping force and the second deformation rate of the gauge length segment of the material under test are obtained at the second time point, which is later than the first time point. Determine whether the second clamping force is less than the first clamping force and whether the second deformation rate is less than the first deformation rate; If so, then calculate the lower limit of the first clamping force drift; If the second clamping force is greater than the lower limit of drift, continue the tensile test; If the second clamping force is less than the lower limit of drift, the clamping state is determined to be abnormal, an alarm command is triggered, and the tensile test is stopped.
[0009] By employing the above technical solution, the ambient temperature of the testing environment is obtained to determine whether the test is under high-temperature conditions. Based on the changes in clamping force and gauge length deformation rate at different time points, combined with the material's high-temperature elastic modulus, the lower limit of clamping force drift is calculated to evaluate the stability of the clamping state. When the clamping force is detected to be below the safety threshold, an alarm is triggered and the tensile test is stopped. This solution significantly improves the reliability and safety of tensile testing under high-temperature conditions, effectively avoids test failures caused by loose clamps or slippage of the test material, and reduces manual intervention.
[0010] Optionally, obtain the fixture's identification code and retrieve the test parameters corresponding to the identification code from the historical test database. The test parameters include at least one of the following: material type, standard clamping force, and peak clamping force. For the same material type, the ratio of peak clamping force to standard clamping force in each tensile test is calculated to obtain the clamping force compliance ratio, and a clamping force compliance ratio sequence is constructed. If the clamping force compliance ratio decreases monotonically for N consecutive times in the clamping force compliance ratio sequence and the last clamping force compliance ratio is lower than the preset ratio of the initial clamping force compliance ratio, then obtain the reference clamping force waveform when the clamp is closed under no-load conditions. Extract the fluctuation amplitude and fluctuation frequency from the reference clamping force waveform; The wear level of the fixture is obtained based on the fluctuation amplitude, fluctuation frequency, and the pre-trained wear state recognition model. The corrected temperature threshold is obtained by retrieving the corresponding temperature threshold correction coefficient based on the wear level.
[0011] By adopting the above technical solution, the fixture's identification code is obtained and its corresponding historical test database is retrieved. The changing trend of the clamping force compliance ratio sequence is analyzed in conjunction with material type analysis to identify the fixture's wear condition and correct the temperature threshold. This solution significantly improves the accuracy of fixture condition assessment and the adaptability of test parameters, effectively avoiding test deviations or failures caused by fixture aging, and reducing repeated testing and manual intervention.
[0012] Optionally, obtain the cumulative number of times the fixture has been used; If the cumulative number of uses is less than the preset break-in period threshold, the fixture is determined to be in the mechanical break-in stage; Calculate the decay slope of the clamping force compliance ratio sequence when the fixture is in the mechanical break-in stage; Determine whether the attenuation slope is less than the preset break-in attenuation slope threshold; If so, the decline in the clamping force compliance rate is considered a normal break-in period. If not, then execute the step of obtaining the reference clamping force waveform when the clamp is closed under no-load if the clamping force compliance ratio decreases monotonically for N consecutive times in the clamping force compliance ratio sequence and the last clamping force compliance ratio is lower than the preset ratio of the initial clamping force compliance ratio.
[0013] By adopting the above technical solution, the cumulative number of uses of the fixture is obtained to determine whether it is in the mechanical break-in stage. Combined with the decay slope of the clamping force compliance ratio sequence, the performance change is identified as either normal break-in or abnormal degradation. When an abnormality is determined, the baseline clamping force waveform is further triggered for acquisition and wear state analysis, and the temperature threshold is corrected. This solution significantly improves the scientific rigor of fixture condition assessment and the reliability of the testing process, effectively avoiding premature replacement or malfunction due to misjudgment.
[0014] Optionally, depending on the material type, determine whether the material to be tested is a composite material; If so, obtain the composite structure information of the material to be tested, which includes the surface material and the inner material. Query the material database and obtain the upper limit of the first safety clamping force corresponding to the surface material and the lower limit of the second anti-slip clamping force corresponding to the inner material; Determine whether the upper limit of the first safety clamping force is greater than the lower limit of the second anti-slip clamping force; If so, the optimal clamping force is set to any value between the lower limit of the second anti-slip clamping force and the upper limit of the first safe clamping force; If not, output a clamping parameter conflict warning signal and pause the clamp closing operation until a user confirmation command is received.
[0015] By employing the above technical solution, the system identifies whether the material to be tested is a composite material. After confirmation, it obtains information on the surface and inner layer materials, and retrieves the corresponding upper limit of safe clamping force and lower limit of anti-slip clamping force from the material database. It intelligently assesses parameter compatibility and sets the optimal clamping force. If parameters conflict, an alert is triggered and clamp operation is paused until user confirmation. This solution significantly improves the safety of composite material clamping parameter settings, effectively preventing sample damage or test failure due to improper clamping.
[0016] Optionally, the interfacial bonding strength between the surface material and the inner material of the material to be tested can be obtained; Obtain the surface hardness of the surface material and the inner hardness of the inner material of the material to be tested, and calculate the hardness ratio of the surface hardness to the inner hardness. The clamping force attenuation coefficient is determined based on the hardness ratio. Calculate the initial corrected clamping force based on the optimal clamping force and the clamping force attenuation coefficient; Calculate the contact pressure exerted by the clamp on the surface of the material under test based on the initial corrected clamping force and the preset contact area between the clamp and the material under test; Determine whether the pressure at the contact surface is greater than the interfacial bonding strength; If so, reduce the initial corrected clamping force so that the pressure on the corrected contact surface does not exceed the interfacial bonding strength, and use the reduced initial corrected clamping force as the optimal clamping force. If not, the initial corrected clamping force is taken as the optimal clamping force.
[0017] By employing the above technical solution, the surface and inner layer materials, interfacial bonding strength, and hardness ratio of the composite material under test are obtained. The clamping force attenuation coefficient and initial corrected clamping force are calculated, and the final clamping force is adjusted based on the comparison between contact surface pressure and interfacial bonding strength. This solution significantly improves the scientific rigor and safety of clamping force setting, effectively avoiding interfacial delamination or damage to the test material due to excessive pressure.
[0018] Optionally, identify whether the surface material of the material to be tested is an anisotropic material; If so, obtain the surface texture image of the surface material; The surface texture image is transformed in the frequency domain, and the dominant frequency direction of the texture is extracted as the candidate dominant direction of the anisotropic material. Obtain the standard principal directions corresponding to anisotropic materials in the material database, and calculate the orientation deviation angle between the candidate principal directions and the standard principal directions; Determine whether the directional deviation angle is less than a preset deviation threshold; If so, the candidate main direction shall be taken as the actual main direction; If not, an error message is issued indicating an abnormal candidate principal direction, and the standard principal direction in the material database is used as the actual principal direction.
[0019] By employing the above technical solution, the method identifies whether the material under test is anisotropic, extracts candidate principal directions based on frequency domain analysis of surface texture images, and performs deviation verification and correction by combining these with standard principal directions from a material database. This solution effectively improves the accuracy and reliability of principal direction determination, avoiding mechanical testing deviations caused by misjudgment of direction.
[0020] Secondly, this application provides a clamping force control system, which adopts the following technical solution: A clamping force control system, comprising: The acquisition module is used to acquire the material type of the material to be tested. The calculation module is used to call the optimal clamping force and preset test height corresponding to the material type in the testing module; control the crossbeam to move to the preset test height and control the clamps of the electronic universal testing machine to close, applying an initial clamping force to the material to be tested; after the initial clamping force reaches the optimal clamping force, a tensile test is performed on the material to be tested, controlling the crossbeam of the testing machine to run at a preset tensile rate, applying a tensile load to the sample axially; during the tensile test, the actual clamping force is monitored in real time; it is determined whether the actual clamping force exceeds the clamping force threshold range; if not, the step of monitoring the actual clamping force in real time during the tensile test is executed until the material to be tested breaks; if so, a test alarm command is triggered and the actual clamping force is recorded; The output module is used to correct the optimal clamping force based on the recorded actual clamping force after the tensile test.
[0021] By adopting the above technical solution, the acquisition module accurately identifies the material type of the material to be tested; the calculation module calls the optimal clamping force and preset test height matched to the material type, controls the testing machine to perform clamping and tensile testing, and monitors the clamping force in real time during the test, alarming and recording data when the limit is exceeded; the output module corrects the optimal clamping force based on the recorded data after the test. This solution significantly improves the accuracy of clamping force control and the safety of the testing process, effectively avoids sample slippage, crushing, or equipment malfunction caused by improper clamping force, reduces manual debugging and repeated testing, ensures the reliability of tensile data, and strongly supports the efficient and stable operation of mechanical testing.
[0022] Thirdly, this application provides a smart terminal, which adopts the following technical solution: A smart terminal includes a memory and a processor, wherein the memory stores a computer program that can be loaded by the processor and executed as described above.
[0023] Fourthly, this application provides a computer storage medium capable of storing corresponding programs, which facilitates improved testing efficiency and precise matching of clamping forces, and adopts the following technical solution: A computer-readable storage medium storing a computer program that can be loaded by a processor and executed by any of the above-described clamping force control methods.
[0024] In summary, this application includes at least one of the following beneficial technical effects: 1. The acquisition module accurately identifies the material type of the material to be tested; the calculation module calls the optimal clamping force and preset test height matched to the material type, controls the testing machine to perform precise clamping and tensile testing, and monitors the clamping force in real time during the test, automatically alarming and recording data when the limit is exceeded; the output module corrects the optimal clamping force based on the recorded data after the test. This solution significantly improves the accuracy of clamping force control and the safety of the testing process, effectively avoiding sample slippage, crushing, or equipment malfunction caused by improper clamping force, reducing manual debugging and repeated testing, ensuring the reliability of tensile data, and strongly supporting the efficient and stable operation of material mechanical property testing. 2. Obtain the ambient temperature of the test environment to determine if it is under high-temperature conditions. Based on the changes in clamping force and gauge length deformation rate at different time points, and combined with the material's high-temperature elastic modulus, calculate the lower limit of clamping force drift to evaluate the stability of the clamping state. When the clamping force is detected to be below the safety threshold, trigger an alarm and stop the tensile test. This solution significantly improves the reliability and safety of tensile testing under high-temperature conditions, effectively avoids test failures caused by loose clamps or slippage of the test material, and reduces manual intervention. 3. The system identifies whether the material to be tested is a composite material, and after confirmation, obtains its surface and inner layer material information. It then retrieves the corresponding upper limit of safe clamping force and lower limit of anti-slip clamping force from the material database, intelligently assesses parameter compatibility, and sets the optimal clamping force. If parameters conflict, an alert is triggered, and clamp operation is paused until user confirmation. This solution significantly improves the safety of composite material clamping parameter settings, effectively avoiding sample damage or test failure due to improper clamping. Attached Figure Description
[0025] Figure 1 This is a flowchart illustrating a clamping force control method provided in an embodiment of this application.
[0026] Figure 2 This is a flowchart illustrating a method for detecting abnormal clamping states at high temperatures, provided in an embodiment of this application.
[0027] Figure 3 This is a schematic flowchart of a temperature threshold correction method based on fixture wear state provided in an embodiment of this application.
[0028] Figure 4This is a flowchart illustrating a method for identifying the running-in status of a fixture, as provided in an embodiment of this application.
[0029] Figure 5 This is a flowchart illustrating a method for setting clamping parameters for composite materials, as provided in an embodiment of this application.
[0030] Figure 6 This is a flowchart illustrating an optimal clamping force correction method based on interface strength provided in an embodiment of this application.
[0031] Figure 7 This is a flowchart illustrating a method for identifying the main direction of anisotropic materials provided in an embodiment of this application.
[0032] Figure 8 This is a schematic diagram of a clamping force control system provided in an embodiment of this application. Detailed Implementation
[0033] To make the purpose, technical solution, and advantages of this application clearer, the following description is provided in conjunction with the appendix. Figures 1 to 8 The present application will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the application.
[0034] This application discloses a clamping force control method. (Refer to...) Figure 1 The method includes: Step S101: Obtain the material type of the material to be tested.
[0035] The material to be tested refers to the specimen that is about to undergo mechanical property testing. It can be a metal, plastic, polymer material or composite material, etc., and is used for tensile testing on an electronic universal testing machine.
[0036] Material type refers to the type of material to be tested, such as steel, aluminum, plastic, rubber, or composite materials, and is used to distinguish the clamping force and test conditions required for different materials in mechanical testing.
[0037] Material type is usually obtained by the operator manually inputting it into the system based on the sample information.
[0038] Step S102: Call the optimal clamping force and preset test height corresponding to the material type in the test module.
[0039] The optimal clamping force refers to the clamping force that, during tensile testing, can reliably fix the material under test to prevent slippage without causing local damage or premature breakage of the sample due to excessive clamping.
[0040] The preset test height refers to the target position of the crossbeam that is set in advance according to the sample type and test requirements before the tensile test begins. The crossbeam will automatically move to this height before the test.
[0041] Step S103: Control the crossbeam to move to the preset test height and control the clamps of the electronic universal testing machine to close, and apply an initial clamping force to the material to be tested.
[0042] Initial clamping force refers to the pre-tightening force applied to the material to be tested when the clamps are closed before the tensile test.
[0043] Step S104: After the initial clamping force reaches the optimal clamping force, perform a tensile test on the material to be tested, and control the crossbeam to run at a preset tensile rate.
[0044] After the initial clamping force reaches the optimal clamping force, the tensile test is started, and the crossbeam is controlled to move at a preset tensile rate to apply a tensile load to the material to be tested.
[0045] Step S105: During the tensile test, monitor the actual clamping force in real time.
[0046] The actual clamping force refers to the clamping force applied by the fixture to the material under test in real time during the tensile test. Its magnitude may vary due to specimen deformation or slippage.
[0047] The clamping force data is collected in real time by sensors installed in the clamping head area.
[0048] Step S106: Determine whether the actual clamping force exceeds the clamping force threshold range.
[0049] The purpose of this judgment is to prevent excessive clamping force from damaging the material under test or insufficient clamping force from causing the material to slip, thus ensuring the accuracy and reliability of the tensile test results.
[0050] Step S107: If not, then perform the step of monitoring the actual clamping force in real time during the tensile test until the material under test breaks.
[0051] If the actual clamping force does not exceed the threshold range, the operation of real-time monitoring of clamping force will be continuously performed in a loop to ensure that the clamping state is stable throughout the stretching process until the material under test breaks.
[0052] Step S108: If yes, trigger the test alarm command and record the actual clamping force.
[0053] When the actual clamping force exceeds the clamping force threshold range, a test alarm command is triggered and the abnormal clamping force data is recorded, providing a basis for adjusting the optimal clamping force in subsequent tensile tests.
[0054] Step S109: After the tensile test is completed, the optimal clamping force is corrected based on the recorded actual clamping force.
[0055] After the tensile test, the existing optimal clamping force is weighted and averaged or slightly adjusted based on the recorded actual clamping force, so that it gradually approaches a more stable and reliable optimal clamping force.
[0056] For example, if the current optimal clamping force is 100N, and the actual clamping force recorded in a tensile test is 95N without slippage or damage, then the optimal clamping force can be adjusted to (100×0.7+95×0.3)=98.5N.
[0057] By adopting the above technical solution, the material type of the material to be tested is obtained, the optimal clamping force and preset test height are selected, and the testing machine is controlled to accurately apply the initial clamping force. During the tensile test, the actual clamping force change is monitored in real time. If the threshold is exceeded, an alarm is triggered and data is recorded. After the test, the optimal clamping force is dynamically corrected based on feedback. This solution significantly improves the accuracy and adaptability of the optimal clamping force setting, effectively avoids sample slippage or damage caused by improper clamping, enhances the automation and intelligence level of the tensile testing process, and improves material testing efficiency.
[0058] This application discloses a method for detecting abnormal clamping states at high temperatures. (Refer to...) Figure 2 The method includes: Step S201: Obtain the ambient temperature of the test environment.
[0059] The ambient temperature was obtained using a temperature sensor located near the tensile testing equipment.
[0060] Step S202: Determine whether the ambient temperature is higher than the temperature threshold.
[0061] The purpose of this assessment is to identify whether the tensile test is conducted under high-temperature conditions, thereby determining whether monitoring for clamping force drift at high temperatures needs to be initiated.
[0062] Step S203: If yes, then obtain the first clamping force at the first time point and the first deformation rate of the gauge length segment of the material to be tested.
[0063] The first time point refers to a specific sampling moment at the beginning of the tensile test after the ambient temperature is higher than the temperature threshold. It is used to obtain the first clamping force and deformation rate as a benchmark for subsequent comparisons.
[0064] The first clamping force refers to the initial clamping force applied to the material to be tested by the fixture at the first time point. The method for obtaining the first clamping force is the same as the method for obtaining the actual clamping force in step S105.
[0065] The first deformation rate refers to the deformation per unit time of the gauge length of the test material at the first time point during the tensile process, reflecting the initial deformation rate of the material under high temperature conditions. The gauge length is a specific length region on the tensile specimen used to measure deformation, and its ends are usually marked.
[0066] If the ambient temperature is not higher than the temperature threshold, then normal monitoring of the actual clamping force is sufficient.
[0067] Step S204: Obtain the second clamping force and the second deformation rate of the gauge length segment of the material under test at the second time point, the second time point being later than the first time point.
[0068] The second time point refers to the monitoring moment selected after the first time point for obtaining the second clamping force and the second deformation rate again.
[0069] The second clamping force refers to the real-time clamping force value measured at the second time point, which represents the clamping force applied by the fixture to the material to be measured. The method of obtaining the second clamping force is the same as the method of obtaining the actual clamping force in step S105.
[0070] The second deformation rate refers to the rate of deformation of the gauge length of the material under test per unit time, measured at the second time point.
[0071] Step S205: Determine whether the second clamping force is less than the first clamping force and whether the second deformation rate is less than the first deformation rate.
[0072] The purpose of the judgment is to identify whether the clamping force and deformation rate decrease synchronously, thereby assessing whether the material under test has entered the relaxation or failure stage.
[0073] Step S206: If yes, calculate the lower limit of the first clamping force drift.
[0074] The drift lower limit refers to the minimum acceptable decrease in the first clamping force due to material factors during the test, and is used to determine whether the clamping state is still within the effective control range.
[0075] The drift lower limit is calculated based on the first clamping force, corrected by the product of the first deformation rate and the material's high-temperature elastic modulus. This product reflects the stiffness reduction of the material at high temperatures. A corresponding proportion is then subtracted from the first clamping force to obtain the minimum allowable clamping force value. The high-temperature elastic modulus of the material is generally a value calibrated experimentally. For example, if the first clamping force is 1000 N, the first deformation rate is 0.1 mm / s, and the elastic modulus of the material at high temperatures is 100 GPa, the deformation rate and elastic modulus can be multiplied first to obtain a correction amount reflecting the stiffness reduction trend. Then, the influence of this correction amount is subtracted from the first clamping force according to an empirical proportion, ultimately yielding the drift lower limit, which is approximately 980 N.
[0076] If the second clamping force is not less than the first clamping force or the second deformation rate is not less than the first deformation rate, then there is no need to calculate the lower limit of the clamping force drift, and the magnitude of the clamping force and the deformation rate continue to be monitored.
[0077] Step S207: If the second clamping force is greater than the lower limit of drift, continue the tensile test.
[0078] If the second clamping force is higher than the lower limit of drift, it indicates that the clamping state is stable and the material has not experienced significant relaxation or failure. Therefore, the tensile test is continued.
[0079] Step S208: If the second clamping force is less than the lower limit of drift, the clamping state is determined to be abnormal, an alarm command is triggered, and the tensile test is stopped.
[0080] When the second clamping force is lower than the drift limit, it indicates that the clamping state is abnormal and there may be a risk of the material under test becoming loose or slipping. An alarm will be triggered and the tensile test will be terminated to prevent data distortion.
[0081] By employing the above technical solution, the ambient temperature of the testing environment is obtained to determine whether the test is under high-temperature conditions. Based on the changes in clamping force and gauge length deformation rate at different time points, combined with the material's high-temperature elastic modulus, the lower limit of clamping force drift is calculated to evaluate the stability of the clamping state. When the clamping force is detected to be below the safety threshold, an alarm is triggered and the tensile test is stopped. This solution significantly improves the reliability and safety of tensile testing under high-temperature conditions, effectively avoids test failures caused by loose clamps or slippage of the test material, and reduces manual intervention.
[0082] This application discloses a temperature threshold correction method based on fixture wear conditions. (Refer to...) Figure 3 The method includes: Step S301: Obtain the fixture's identification code and retrieve the test parameters corresponding to the identification code from the historical test database. The test parameters include at least one of the following: material type, standard clamping force, and peak clamping force.
[0083] An identification code is a coded information used to uniquely identify a fixture, usually in the form of numbers, letters or a combination thereof, and is fixed on the fixture.
[0084] Test parameters refer to the key performance data recorded by the fixture during historical testing, which are used to represent the clamping performance benchmark of the fixture for different materials.
[0085] The identification code is obtained by reading the information in the electronic tag, QR code or RFID chip set on the fixture to obtain its unique identification code, and then using the identification code as an index to query the pre-stored historical test database to retrieve the test parameters associated with the fixture.
[0086] Step S302: For the same material type, calculate the ratio of peak clamping force to standard clamping force in each tensile test to obtain the clamping force compliance ratio and construct a clamping force compliance ratio sequence.
[0087] The clamping force compliance ratio refers to the ratio of the peak clamping force obtained in each tensile test to the corresponding standard clamping force in multiple tensile tests for the same material type.
[0088] The clamping force compliance ratio sequence refers to the sequence formed by arranging the clamping force compliance ratios obtained in each tensile test of the same material type in the order of the tests.
[0089] Step S303: If the clamping force compliance ratio decreases monotonically for N consecutive times in the clamping force compliance ratio sequence and the last clamping force compliance ratio is lower than the preset ratio of the initial clamping force compliance ratio, then obtain the reference clamping force waveform when the clamp is closed under no-load conditions.
[0090] The reference clamping force waveform refers to the signal curve of the clamping force changing over time, which is collected by the sensor when the clamp completes the closing action without the load of the material to be measured. It is used to represent the mechanical response characteristics of the clamp itself.
[0091] Setting a preset ratio where the clamping force compliance rate decreases monotonically over N consecutive cycles and the final clamping force compliance rate is lower than the initial clamping force compliance rate is to eliminate random fluctuations and ensure that the clamping performance does indeed show a continuous deterioration trend, thereby enabling further diagnosis of the clamping condition.
[0092] Step S304: Extract the fluctuation amplitude and fluctuation frequency from the reference clamping force waveform.
[0093] Fluctuation amplitude refers to the maximum deviation of the actual clamping force from its average value in the reference clamping force waveform, reflecting the degree of mechanical vibration or instability during the unloaded closure process of the clamp.
[0094] Fluctuation frequency refers to the number of cycles of clamping force fluctuation per unit time in the reference clamping force waveform, reflecting the speed of mechanical vibration during the unloaded closing process of the clamp.
[0095] By collecting time series data of the reference clamping force waveform, signal processing methods are used to identify the time interval between adjacent peaks or valleys in the waveform, the reciprocal of which is calculated to obtain the fluctuation frequency, and the fluctuation amplitude is determined by the difference between the peak and valley values.
[0096] Step S305: Obtain the wear level of the fixture based on the fluctuation amplitude, fluctuation frequency, and the pre-trained wear state recognition model.
[0097] Wear level refers to the degree of material loss and performance degradation of a fixture due to long-term use. It is usually divided into light wear, moderate wear and heavy wear, which reflects whether the current wear condition affects the clamping accuracy or requires maintenance or replacement.
[0098] The extracted fluctuation amplitude and fluctuation frequency are used as features and input into the pre-trained wear state recognition model to output the corresponding wear level. The pre-trained wear state recognition model is trained in advance based on the correspondence between historical fluctuation amplitude, fluctuation frequency and wear level.
[0099] Step S306: Retrieve the corresponding temperature threshold correction coefficient according to the wear level to obtain the corrected temperature threshold.
[0100] Based on the determined wear level, the temperature threshold correction coefficient corresponding to the wear level is retrieved from the preset mapping relationship, and the original temperature threshold is multiplied by the temperature threshold correction coefficient to obtain the corrected temperature threshold that is adapted to the current wear state.
[0101] By adopting the above technical solution, the fixture's identification code is obtained and its corresponding historical test database is retrieved. The changing trend of the clamping force compliance ratio sequence is analyzed in conjunction with material type analysis to identify the fixture's wear condition and correct the temperature threshold. This solution significantly improves the accuracy of fixture condition assessment and the adaptability of test parameters, effectively avoiding test deviations or failures caused by fixture aging, and reducing repeated testing and manual intervention.
[0102] This application discloses a method for identifying the break-in state of a fixture. (Refer to...) Figure 4 The method includes: Step S401: Obtain the cumulative number of times the fixture has been used.
[0103] By reading the historical operation logs stored in the storage unit associated with the fixture, the records of each fixture action are extracted and accumulated to obtain the cumulative number of uses.
[0104] Step S402: If the cumulative number of uses is less than the preset break-in period threshold, the fixture is determined to be in the mechanical break-in stage.
[0105] The mechanical break-in stage refers to the transition process in which the surface of a fixture gradually eliminates micro-imperfections, improves fitting accuracy, and tends to a stable working state through repeated contact and friction during its initial use.
[0106] Step S403: When the fixture is in the mechanical break-in stage, calculate the decay slope of the clamping force compliance ratio sequence.
[0107] By obtaining the clamping force compliance rate of the fixture during each use in the mechanical break-in phase, and arranging the compliance rates sequentially according to the number of uses, the trend of the clamping force compliance rate sequence is fitted with a straight line. The slope of the resulting straight line is the decay slope. The fitting is usually performed using the least squares method to perform linear regression on the clamping force compliance rate sequence and its corresponding number of uses to obtain an optimal fitting straight line, the slope of which is the decay slope.
[0108] Step S404: Determine whether the attenuation slope is less than the preset break-in attenuation slope threshold.
[0109] The purpose of the assessment is to confirm whether the rate of decrease in clamping force after the break-in period has stabilized or reached an acceptable level.
[0110] Step S405: If so, the decline in the clamping force compliance ratio is considered normal break-in.
[0111] Normal break-in refers to a slight and controllable decline in clamping force during the initial use due to minor unevenness on the surface of the parts or material adaptation adjustments. This is a natural phenomenon in the early stages of operation and does not affect long-term stability and functional reliability.
[0112] Step S406: If not, then execute the step of obtaining the reference clamping force waveform when the clamp is closed under no-load if the clamping force compliance ratio decreases monotonically for N consecutive times in the clamping force compliance ratio sequence and the last clamping force compliance ratio is lower than the preset ratio of the initial clamping force compliance ratio.
[0113] When the attenuation slope is not less than the preset break-in attenuation slope threshold, it is determined whether the clamping force shows a continuous deterioration trend. If the compliance ratio decreases monotonically for N consecutive times and the last value is significantly lower than the initial value, the acquisition of the reference clamping force waveform under the no-load closed state of the fixture is triggered to analyze whether there are abnormalities such as mechanical wear or performance degradation of the fixture.
[0114] By adopting the above technical solution, the cumulative number of uses of the fixture is obtained to determine whether it is in the mechanical break-in stage. Combined with the decay slope of the clamping force compliance ratio sequence, the performance change is identified as either normal break-in or abnormal degradation. When an abnormality is determined, the baseline clamping force waveform is further triggered for acquisition and wear state analysis, and the temperature threshold is corrected. This solution significantly improves the scientific rigor of fixture condition assessment and the reliability of the testing process, effectively avoiding premature replacement or malfunction due to misjudgment.
[0115] This application discloses a method for setting clamping parameters for composite materials. (Refer to...) Figure 5 The method includes: Step S501: Determine whether the material to be tested is a composite material based on the material type.
[0116] Composite materials are structural materials composed of two or more materials with different properties combined on a macroscopic scale. Each component remains relatively independent but works synergistically to achieve mechanical or functional properties that cannot be achieved by a single material. Examples include carbon fiber reinforced resin, fiberglass, or metal matrix composites.
[0117] The purpose of judging the material to be tested is to distinguish its clamping characteristics. Since the mechanical properties of the surface and inner layers of composite materials are usually quite different, if they are treated as a single material, it is easy to cause the surface to be damaged by excessive clamping force or to slip due to insufficient clamping force, which will affect the safety and accuracy of the test.
[0118] Step S502: If yes, then obtain the composite structure information of the material to be tested, which includes the surface material and the inner material.
[0119] Composite structure information refers to the combination of surface and inner layer materials in composite materials, reflecting the compositional differences of materials at different depths.
[0120] Composite structure information can be obtained from material files pre-stored in a database, and the corresponding data can be directly retrieved before testing.
[0121] If the material to be tested is not a composite material, it will be treated as a single material.
[0122] Step S503: Query the material database and obtain the upper limit of the first safety clamping force corresponding to the surface material and the lower limit of the second anti-slip clamping force corresponding to the inner material.
[0123] The first safety clamping force limit refers to the maximum clamping force that the clamp can apply without damaging the surface material, and is used to prevent surface crushing, scratching or deformation.
[0124] The second lower limit of anti-slip clamping force refers to the minimum clamping force that the fixture needs to apply to prevent the inner layer material from slipping or shifting during the tensile test.
[0125] The first safety clamping force and the second anti-slip clamping force lower limit are obtained by inputting the material types of the surface material and the inner material into the material database, retrieving and outputting the first safety clamping force upper limit and the second anti-slip clamping force lower limit associated with the material to be tested.
[0126] Step S504: Determine whether the upper limit of the first safety clamping force is greater than the lower limit of the second anti-slip clamping force.
[0127] The purpose of this judgment is to ensure that there is a feasible clamping force range that neither damages the surface material nor causes the inner material to slip, thereby ensuring the safety and effectiveness of the testing process.
[0128] Step S505: If so, the optimal clamping force is set to any value between the lower limit of the second anti-slip clamping force and the upper limit of the first safe clamping force.
[0129] After confirming the existence of a feasible clamping force range, any value within it is selected as the optimal clamping force to simultaneously meet the requirements of anti-slip and safe clamping.
[0130] Step S506: If not, output a clamping parameter conflict warning signal and pause the clamp closing operation until a user confirmation command is received.
[0131] When the upper limit of the first safety clamping force is not greater than the lower limit of the second anti-slip clamping force, the clamp is prevented from closing in time. The clamp is prevented from closing by sending a prompt to the user terminal and waiting for the user's confirmation instruction, or by checking whether it has been replaced with a suitable special clamp, thereby avoiding material damage or test failure due to unmet clamping conditions.
[0132] By employing the above technical solution, the system identifies whether the material to be tested is a composite material. After confirmation, it obtains information on the surface and inner layer materials, and retrieves the corresponding upper limit of safe clamping force and lower limit of anti-slip clamping force from the material database. It intelligently assesses parameter compatibility and sets the optimal clamping force. If parameters conflict, an alert is triggered and clamp operation is paused until user confirmation. This solution significantly improves the safety of composite material clamping parameter settings, effectively preventing sample damage or test failure due to improper clamping.
[0133] This application discloses an optimal clamping force correction method based on interface strength. (Refer to...) Figure 6 The method includes: Step S601: Obtain the interfacial bonding strength between the surface material and the inner material of the material to be tested.
[0134] Interfacial bonding strength refers to the ability of the surface material and the inner material of the tested material to resist relative separation or slippage at the contact interface, reflecting the degree of adhesion or bonding between the two layers of materials.
[0135] The interface bonding strength can be directly retrieved from the process parameter library, which pre-stores historical test data corresponding to specific material combinations under standard process conditions.
[0136] Step S602: Obtain the surface hardness of the surface material and the inner hardness of the inner material of the material to be tested, and calculate the hardness ratio of the surface hardness to the inner hardness.
[0137] Surface hardness refers to the ability of the outermost surface area of a material to resist localized plastic deformation or indentation.
[0138] Inner layer hardness refers to the ability of the inner matrix region of a material to resist indentation or plastic deformation after the surface layer is removed.
[0139] The hardness ratio refers to the ratio of the surface hardness to the inner hardness, and is used to represent the relative difference between the surface material and the inner material in their ability to resist plastic deformation.
[0140] Surface hardness and inner hardness are generally obtained by directly performing a hardness test on the surface of the material to be tested to obtain the surface hardness, and then removing the surface layer and performing a hardness test on the exposed internal area under the same conditions to obtain the inner hardness. Hardness testing refers to applying a specific load to the material surface through methods such as indentation, scratching, or springback and measuring its ability to resist plastic deformation or failure.
[0141] Step S603: Determine the clamping force attenuation coefficient based on the hardness ratio.
[0142] The clamping force attenuation coefficient is determined based on the comparison between the hardness ratio and the preset ratio threshold. When the hardness ratio is less than the preset ratio threshold, it indicates that the surface layer is relatively soft and prone to deformation. Therefore, the clamping force attenuation coefficient is set to be greater than 1 to compensate for the decrease in clamping performance. Otherwise, the clamping force attenuation coefficient is set to 1.
[0143] Step S604: Calculate the initial corrected clamping force based on the optimal clamping force and the clamping force attenuation coefficient.
[0144] The initial corrected clamping force refers to the initial clamping force value obtained after adjustment based on the optimal clamping force and the clamping force attenuation coefficient. It is used to compensate for the clamping force attenuation that may be caused by material deformation during the actual clamping process.
[0145] The initial corrected clamping force is obtained by the result of the optimal clamping force and the clamping force attenuation coefficient.
[0146] Step S605: Calculate the contact pressure exerted by the clamp on the surface of the material to be tested based on the initial corrected clamping force and the preset contact area between the clamp and the material to be tested.
[0147] The preset contact area refers to the theoretical contact area between the fixture and the material to be tested.
[0148] Contact surface pressure refers to the pressure per unit area generated when the initial corrective clamping force applied by the fixture is evenly distributed over the preset contact area.
[0149] The contact surface pressure is obtained by dividing the initial corrected clamping force by the preset contact area between the clamp and the material to be tested, which is the clamping force per unit area.
[0150] Step S606: Determine whether the pressure on the contact surface is greater than the interfacial bonding strength.
[0151] The purpose of the judgment is to ensure that the pressure applied by the fixture will not damage the bond between the material under test and the contact interface, and to avoid slippage, damage or failure during the test.
[0152] Step S607: If so, reduce the initial corrected clamping force so that the pressure on the corrected contact surface does not exceed the interfacial bonding strength, and use the reduced initial corrected clamping force as the optimal clamping force.
[0153] If the contact surface pressure is greater than the interfacial bonding strength, the contact surface pressure can be reduced to a safe range by lowering the initial corrected clamping force, thereby determining an optimal clamping force that ensures effective clamping without damaging the interfacial bonding.
[0154] Step S608: If not, then the initial corrected clamping force is taken as the optimal clamping force.
[0155] When the pressure on the contact surface is not greater than the interfacial bonding strength, it indicates that the initial corrected clamping force has met the clamping requirements and will not damage the interface. Therefore, the initial corrected clamping force is taken as the optimal clamping force.
[0156] By employing the above technical solution, the surface and inner layer materials, interfacial bonding strength, and hardness ratio of the composite material under test are obtained. The clamping force attenuation coefficient and initial corrected clamping force are calculated, and the final clamping force is adjusted based on the comparison between contact surface pressure and interfacial bonding strength. This solution significantly improves the scientific rigor and safety of clamping force setting, effectively avoiding interfacial delamination or damage to the test material due to excessive pressure.
[0157] This application discloses a method for identifying the principal direction of anisotropic materials. (Refer to...) Figure 7 The method includes: Step S701: Identify whether the surface material of the material to be tested is an anisotropic material.
[0158] Anisotropic materials are materials whose physical or mechanical properties differ depending on the direction. For example, the elastic modulus of carbon fiber composites differs significantly along the fiber direction and perpendicular to the direction.
[0159] Anisotropic materials can be identified by querying material property information in a material database, such as detecting the presence of obvious directional fibers, grain orientation, or periodic texture features.
[0160] Step S702: If yes, then obtain the surface texture image of the surface material.
[0161] Surface texture images are images that reflect the surface micro-morphology and structural orientation of the material under test. They can present texture information with directional characteristics, such as scratches, fiber orientation, and grain arrangement.
[0162] Surface texture images can be obtained by taking pictures of the material surface with a high-resolution industrial camera under uniform illumination provided by a standard light source, at a fixed angle and focal length, thereby obtaining images that can clearly reflect the directional characteristics of its texture.
[0163] If the surface material of the material to be tested is not anisotropic, there is no need to obtain a surface texture image; the hardness ratio can be calculated directly.
[0164] Step S703: Perform frequency domain transformation on the surface texture image and extract the dominant frequency direction of the texture as the candidate dominant direction of the anisotropic material.
[0165] Frequency domain transformation refers to the process of performing a Fourier transform on a surface texture image to convert the image from the spatial domain to the frequency domain, in order to reveal the frequency distribution characteristics of its periodic structure in different directions.
[0166] The dominant frequency direction of texture refers to the direction corresponding to the frequency component with the most concentrated energy in the frequency domain of the surface texture, reflecting the dominant orientation of the periodic structure of the material surface.
[0167] Candidate principal directions refer to directions initially selected from the dominant frequency directions of the texture that may represent the dominant orientation of the macroscopic physical properties of anisotropic materials.
[0168] Step S704: Obtain the standard principal direction corresponding to the anisotropic material in the material database, and calculate the direction deviation angle between the candidate principal direction and the standard principal direction.
[0169] The standard principal direction refers to the reference direction in which the physical properties of anisotropic materials under ideal or calibrated conditions are pre-stored in the materials database.
[0170] The orientation deviation angle is the smallest angle formed in a plane between the candidate principal direction and the standard principal direction, and is used to quantify the degree of deviation between the two in orientation.
[0171] Step S705: Determine whether the direction deviation angle is less than the preset deviation threshold.
[0172] The purpose of this judgment is to confirm whether the candidate principal direction is sufficiently consistent with the standard principal direction.
[0173] Step S706: If so, then the candidate main direction is taken as the actual main direction.
[0174] When the deviation angle between the candidate principal direction and the standard principal direction is less than the preset deviation threshold, the candidate principal direction is confirmed as the actual principal direction of the material.
[0175] Step S707: If not, issue an error message for the candidate principal direction and call the standard principal direction in the material database as the actual principal direction.
[0176] When the deviation angle between the candidate principal direction and the standard principal direction is not less than the preset deviation threshold, the candidate principal direction is determined to be abnormal and a prompt is issued. At the same time, the standard principal direction in the material database is used as the actual principal direction to ensure the accuracy of subsequent processing.
[0177] By employing the above technical solution, the method identifies whether the material under test is anisotropic, extracts candidate principal directions based on frequency domain analysis of surface texture images, and performs deviation verification and correction by combining these with standard principal directions from a material database. This solution effectively improves the accuracy and reliability of principal direction determination, avoiding mechanical testing deviations caused by misjudgment of direction.
[0178] Based on the same inventive concept, embodiments of this application provide a clamping force control system, referencing... Figure 8 The system includes: The acquisition module 801 is used to acquire the material type of the material to be tested; The calculation module 802 is used to call the optimal clamping force and preset test height corresponding to the material type in the test module; control the crossbeam to move to the preset test height and control the clamps of the electronic universal testing machine to close, applying an initial clamping force to the material to be tested; after the initial clamping force reaches the optimal clamping force, a tensile test is performed on the material to be tested, controlling the crossbeam of the testing machine to run at a preset tensile rate, applying a tensile load to the sample axially; during the tensile test, the actual clamping force is monitored in real time; it is determined whether the actual clamping force exceeds the clamping force threshold range; if not, the step of monitoring the actual clamping force in real time during the tensile test is executed until the material to be tested breaks; if so, a test alarm command is triggered and the actual clamping force is recorded; The output module 803 is used to correct the optimal clamping force based on the recorded actual clamping force after the tensile test.
[0179] By adopting the above technical solution, the acquisition module accurately identifies the material type of the material to be tested; the calculation module calls the optimal clamping force and preset test height matched to the material type, controls the testing machine to perform clamping and tensile testing, and monitors the clamping force in real time during the test, alarming and recording data when the limit is exceeded; the output module corrects the optimal clamping force based on the recorded data after the test. This solution significantly improves the accuracy of clamping force control and the safety of the testing process, effectively avoids sample slippage, crushing, or equipment malfunction caused by improper clamping force, reduces manual debugging and repeated testing, ensures the reliability of tensile data, and strongly supports the efficient and stable operation of mechanical testing.
[0180] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional modules is used as an example. In practical applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above. The specific working process of the system, device, and unit described above can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.
[0181] This application provides a computer-readable storage medium storing a computer program that can be loaded by a processor and executed as a clamping force control method.
[0182] Computer storage media include, for example, USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, optical disks, and other media that can store program code.
[0183] Based on the same inventive concept, embodiments of this application provide a smart terminal, including a memory and a processor, wherein the memory stores a computer program that can be loaded by the processor and executed to control the clamping force.
[0184] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional modules is used as an example. In practical applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above. The specific working process of the system, device, and unit described above can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.
[0185] The above are all preferred embodiments of this application and are not intended to limit the scope of protection of this application. Any feature disclosed in this specification (including the abstract and drawings) may be replaced by other equivalent or similar features unless specifically stated otherwise. That is, unless specifically stated otherwise, each feature is only one example of a series of equivalent or similar features.
Claims
1. A clamping force control method, characterized in that, include: Obtain the material type of the material to be tested; Call the optimal clamping force and preset test height corresponding to the material type in the test module; Control the crossbeam to move to the preset test height and control the clamps of the electronic universal testing machine to close, applying an initial clamping force to the material to be tested; After the initial clamping force reaches the optimal clamping force, a tensile test is performed on the material to be tested, and the crossbeam is controlled to run at a preset tensile rate. During the tensile test, the actual clamping force is monitored in real time; Determine whether the actual clamping force exceeds the clamping force threshold range; If not, then the step of monitoring the actual clamping force in real time during the tensile test is performed until the material under test breaks. If so, a test alarm command will be triggered, and the actual clamping force will be recorded; After the tensile test, the optimal clamping force is corrected based on the recorded actual clamping force.
2. The clamping force control method according to claim 1, characterized in that, Before determining whether the actual clamping force exceeds the clamping force threshold range, the following steps are included: Obtain the ambient temperature of the test environment; Determine if the ambient temperature is higher than the temperature threshold; If so, then obtain the first clamping force at the first time point and the first deformation rate of the gauge length segment of the material to be tested; The second clamping force and the second deformation rate of the gauge length segment of the material under test are obtained at the second time point, which is later than the first time point. Determine whether the second clamping force is less than the first clamping force and whether the second deformation rate is less than the first deformation rate; If so, then calculate the lower limit of the first clamping force drift; If the second clamping force is greater than the lower limit of drift, continue the tensile test; If the second clamping force is less than the lower limit of drift, the clamping state is determined to be abnormal, an alarm command is triggered, and the tensile test is stopped.
3. The clamping force control method according to claim 2, characterized in that, Before determining whether the ambient temperature is higher than the temperature threshold, the following steps are included: Obtain the fixture's identification code and retrieve the corresponding test parameters from the historical test database. The test parameters include at least one of the following: material type, standard clamping force, and peak clamping force. For the same material type, the ratio of peak clamping force to standard clamping force in each tensile test is calculated to obtain the clamping force compliance ratio, and a clamping force compliance ratio sequence is constructed. If the clamping force compliance ratio sequence shows a monotonically decreasing trend for N consecutive times and the last clamping force compliance ratio is lower than the preset ratio of the initial clamping force compliance ratio, then the reference clamping force waveform when the clamp is closed under no-load conditions is obtained. Extract the fluctuation amplitude and fluctuation frequency from the reference clamping force waveform; The wear level of the fixture is obtained based on the fluctuation amplitude, fluctuation frequency, and the pre-trained wear state recognition model. The corrected temperature threshold is obtained by retrieving the corresponding temperature threshold correction coefficient based on the wear level.
4. The clamping force control method according to claim 3, characterized in that, If the clamping force compliance ratio sequence shows a monotonically decreasing trend for N consecutive clamping force compliance ratios and the last clamping force compliance ratio is lower than a preset ratio of the initial clamping force compliance ratio, then before obtaining the reference clamping force waveform when the clamp is closed under no-load conditions, the following steps are included: Get the cumulative number of times the fixture has been used; If the cumulative number of uses is less than the preset break-in period threshold, the fixture is determined to be in the mechanical break-in stage; Calculate the decay slope of the clamping force compliance ratio sequence when the fixture is in the mechanical break-in stage; Determine whether the attenuation slope is less than the preset break-in attenuation slope threshold; If so, the decline in the clamping force compliance rate is considered a normal break-in period. If not, then execute the step of obtaining the reference clamping force waveform when the clamp is closed under no-load if the clamping force compliance ratio sequence shows a monotonically decreasing N consecutive clamping force compliance ratios and the last clamping force compliance ratio is lower than the preset ratio of the initial clamping force compliance ratio.
5. The clamping force control method according to claim 1, characterized in that, Before invoking the optimal clamping force and preset test height corresponding to the material type in the test module, the following steps are included: Determine whether the material to be tested is a composite material based on its type; If so, obtain the composite structure information of the material to be tested, which includes the surface material and the inner material. Query the material database and obtain the upper limit of the first safety clamping force corresponding to the surface material and the lower limit of the second anti-slip clamping force corresponding to the inner material; Determine whether the upper limit of the first safety clamping force is greater than the lower limit of the second anti-slip clamping force; If so, the optimal clamping force is set to any value between the lower limit of the second anti-slip clamping force and the upper limit of the first safe clamping force; If not, output a clamping parameter conflict warning signal and pause the clamp closing operation until a user confirmation command is received.
6. The clamping force control method according to claim 5, characterized in that, After setting the optimal clamping force to any value between the lower limit of the second anti-slip clamping force and the upper limit of the first safety clamping force, the following steps are included: To obtain the interfacial bonding strength between the surface material and the inner material of the material to be tested; Obtain the surface hardness of the surface material and the inner hardness of the inner material of the material to be tested, and calculate the hardness ratio of the surface hardness to the inner hardness. The clamping force attenuation coefficient is determined based on the hardness ratio. Calculate the initial corrected clamping force based on the optimal clamping force and the clamping force attenuation coefficient; Calculate the contact pressure exerted by the clamp on the surface of the material under test based on the initial corrected clamping force and the preset contact area between the clamp and the material under test; Determine whether the pressure at the contact surface is greater than the interfacial bonding strength; If so, reduce the initial corrected clamping force so that the pressure on the corrected contact surface does not exceed the interfacial bonding strength, and use the reduced initial corrected clamping force as the optimal clamping force. If not, the initial corrected clamping force is taken as the optimal clamping force.
7. The clamping force control method according to claim 6, characterized in that, Before obtaining the surface hardness of the surface material and the inner hardness of the inner material of the material to be tested, and calculating the hardness ratio of the surface hardness to the inner hardness, the following steps are included: Identify whether the surface material of the material to be tested is an anisotropic material; If so, obtain the surface texture image of the surface material; The surface texture image is transformed in the frequency domain, and the dominant frequency direction of the texture is extracted as the candidate dominant direction of the anisotropic material. Obtain the standard principal directions corresponding to anisotropic materials in the material database, and calculate the orientation deviation angle between the candidate principal directions and the standard principal directions; Determine whether the directional deviation angle is less than a preset deviation threshold; If so, the candidate main direction shall be taken as the actual main direction; If not, an error message is issued indicating an abnormal candidate principal direction, and the standard principal direction in the material database is used as the actual principal direction.
8. A clamping force control system, characterized in that, The system is used to execute the clamping force control method as described in any one of claims 1 to 7, comprising: The acquisition module is used to acquire the material type of the material to be tested. The calculation module is used to call the optimal clamping force and preset test height corresponding to the material type in the testing module; control the crossbeam to move to the preset test height and control the clamps of the electronic universal testing machine to close, applying an initial clamping force to the material to be tested; after the initial clamping force reaches the optimal clamping force, a tensile test is performed on the material to be tested, controlling the crossbeam of the testing machine to run at a preset tensile rate, applying a tensile load to the sample axially; during the tensile test, the actual clamping force is monitored in real time; it is determined whether the actual clamping force exceeds the clamping force threshold range; if not, the step of monitoring the actual clamping force in real time during the tensile test is executed until the material to be tested breaks; if so, a test alarm command is triggered and the actual clamping force is recorded; The output module is used to correct the optimal clamping force based on the recorded actual clamping force after the tensile test.
9. A smart terminal, characterized in that, It includes a memory and a processor, wherein the memory stores a computer program that can be loaded by the processor and executed as described in any one of claims 1 to 7.
10. A computer-readable storage medium, characterized in that, The computer program is stored that can be loaded by a processor and execute the method as described in any one of claims 1 to 7.