Fatigue life test system and method

Abstract

The invention provides a fatigue life test system and method, and relates to the technical field of data processing. The fatigue life test system comprises a data acquisition module, a data transmission module and a fatigue life test module, wherein the data acquisition module comprises a sensor sub-module for acquiring data of a point location to be tested; the sensor sub-module comprises a sensor, and the sensor is used for detecting a change signal of the surface of the detected point location in the stress process and sending the change signal to the data transmission module; and the fatigue life test module is used for carrying out fatigue life calculation on the change signal transmitted by the data transmission module and outputting fatigue life information of the tested point location. The arrangement time of the acquisition equipment for acquiring the data of the to-be-tested point position is shortened, a tester does not need to arrange a cable for transmission of a transmission change signal, the data transmission time is further shortened, and the test efficiency of the whole fatigue life test system is further improved.

Description

Technical Field

[0001] The present disclosure relates to the field of data processing technology, and in particular to a fatigue life testing system and method. Background Art

[0002] In related technologies, in order to more accurately evaluate the performance of a locomotive, fatigue life tests need to be performed on key parts of the locomotive's load-bearing components.

[0003] Specifically, during the fatigue life test of the locomotive bogie structure, if you want to obtain the fatigue life of the measuring point, the tester needs to manually perform a series of operations such as cleaning the measuring point, marking, judging whether the strain gauge is consistent with the principal stress direction, pasting the strain gauge, exhausting the pasted strain gauge, and fixing it, in order to complete the data collection of the measuring point. In addition, the tester is also required to manually weld the power supply / signal cable of the strain gauge to the strain gauge and lay a longer cable along the locomotive structure, so that the data processing software can obtain the data of the measuring point based on the cable.

[0004] It can be seen that the related technology has the problem of low efficiency in obtaining data on the measurement point positions, which leads to low test efficiency of the fatigue life test system. Summary of the invention

[0005] The present disclosure provides a fatigue life test system and method to solve the problem of low test efficiency of the fatigue life test system at least to a certain extent.

[0006] According to a first aspect of the present disclosure, a fatigue life test system is provided, characterized in that the system comprises a data acquisition module, a data transmission module and a fatigue life test module, wherein:

[0007] The data acquisition module includes a sensor submodule for collecting data of the point to be measured; the sensor submodule includes a sensor, and the sensor is used to detect the change signal of the surface of the point to be measured during the force process, and send the change signal to the data transmission module;

[0008] The fatigue life test module is used to perform fatigue life calculation on the change signal transmitted by the data transmission module, and output fatigue life information of the measured point.

[0009] In a possible design, a cable for transmitting the change signal is arranged between the data acquisition module and the data transmission module; the sensor submodule also includes a shell and an adsorbable head, and the adsorbable head is used to adsorb the sensor submodule to the object corresponding to the point to be measured; the first end of the shell is connected to the adsorbable head, and the second end of the shell is connected to the cable or is provided with a wire outlet hole for leading out the cable.

[0010] In a possible design, the housing is cylindrical and is used to protect and fix the sensor.

[0011] In a possible design, the adsorbable head is a ring-shaped structure.

[0012] In a possible design, the adsorbable head is a strong magnetic adsorption head, and the strong magnetic adsorption head includes at least two strong magnets, and the at least two strong magnets are arranged in a preset manner.

[0013] In a possible design, the adsorbable head is an adhesive adsorption head, and the adhesive adsorption head includes a first part for adhering to the point to be measured and a second part for adhering to the housing.

[0014] In a possible design, the sensor is a sensor array, which includes at least four sensors, wherein different sensors have different projection positions on the surface of the point to be measured along a preset pattern.

[0015] In one possible design, the system also includes a wireless power supply module, which includes: a current conditioning submodule for converting alternating current into direct current, a microwave transmitting submodule for converting direct current into microwaves and emitting microwaves, a microwave relay submodule for adjusting the direction of power transmission, and a microwave receiving submodule for receiving microwaves and transmitting power to power the sensor.

[0016] According to a second aspect of the present disclosure, a fatigue testing method is provided and applied to any fatigue life testing system described in the first aspect, the method comprising:

[0017] Determine the displacement information corresponding to the change signal collected by the sensor;

[0018] Determine stress information corresponding to the point to be measured according to the displacement information;

[0019] Performing data cleaning on the stress information corresponding to the points to be measured to obtain processed stress information;

[0020] The fatigue life information of the measured point is determined according to the processed stress information and the stress-life SN curve of the object corresponding to the measured point.

[0021] In a possible implementation, determining stress information corresponding to the point to be measured according to the displacement information includes:

[0022] Determine the displacement gradient corresponding to the measured point according to the displacement information;

[0023] The stress value and stress direction are determined according to the obtained displacement gradient and the material properties of the object corresponding to the measured point, so as to determine the stress information corresponding to the measured point.

[0024] The technical solution disclosed in this disclosure has the following beneficial effects:

[0025] In the disclosed embodiment, since the data acquisition module in the fatigue life test system includes a sensor submodule for collecting data of the point to be tested, there is no need for the tester to manually perform a series of operations. The change signal of the surface of the point to be tested during the force process can be detected directly based on the sensor included in the sensor submodule, thereby shortening the layout time of the collection equipment for collecting data of the point to be tested and improving the collection efficiency of the data of the point to be tested. In addition, since the sensor can directly send the change signal to the data transmission module in the fatigue life test system, the fatigue life test module in the fatigue life test system can receive the change signal based on wireless transmission, perform fatigue life calculation on the change signal, and output the corresponding calculation result. In other words, in the disclosed embodiment, there is no need for the tester to arrange cables for the transmission of the change signal, which further shortens the data transmission time and improves the test efficiency of the entire fatigue life test system.

[0026] Other features and advantages of the present disclosure will be described in the following description, and partly become apparent from the description, or be understood by practicing the present disclosure. The purpose and other advantages of the present disclosure can be realized and obtained by the structures particularly pointed out in the written description, claims, and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings required for use in the embodiments of the present disclosure will be briefly introduced below. Obviously, the drawings introduced below are only some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0028] Figure 1 A system architecture diagram of a fatigue life testing system in this exemplary embodiment is shown;

[0029] Figure 2A system architecture diagram showing another fatigue life testing system in this exemplary embodiment;

[0030] Figure 3 A schematic diagram showing the structure of a sensor submodule in this exemplary embodiment is shown;

[0031] Figure 4 A schematic diagram showing a method of adsorbing a sensor submodule onto an object corresponding to a point to be measured in this exemplary embodiment is shown;

[0032] Figure 5 A schematic diagram showing a process of transmitting a change signal by a data transmission module in this exemplary embodiment is shown;

[0033] Figure 6 A schematic diagram showing a wireless power supply module in this exemplary embodiment;

[0034] Figure 7 A schematic flow chart showing a fatigue life test method in this exemplary embodiment;

[0035] Figure 8 A schematic diagram showing the arrangement of multiple displacement sensors inside a sensor in this exemplary embodiment;

[0036] Fig. 9 A schematic diagram showing surface deformation of a measured point before and after deformation in this exemplary embodiment is shown;

[0037] Fig.10 A schematic diagram showing the principle of calculating the surface strain of a measured point in this exemplary embodiment;

[0038] Fig.11 A schematic diagram showing the process of another fatigue life test method in this exemplary embodiment. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical solutions and advantages of the present disclosure clearer, the technical solutions in the embodiments of the present disclosure will be clearly and completely described below in conjunction with the drawings in the embodiments of the present disclosure. Obviously, the described embodiments are only part of the embodiments of the present disclosure, rather than all of the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present disclosure. In the absence of conflict, the embodiments in the present disclosure and the features in the embodiments can be arbitrarily combined with each other. In addition, although the logical order is shown in the flow chart, in some cases, the steps shown or described can be performed in an order different from that here.

[0040] The term "comprising" and any variations thereof in the specification and claims of the present disclosure are intended to cover non-exclusive protection. For example, a process, method, system, product or device comprising a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products or devices.

[0041] The following is a description of exemplary embodiments of the present disclosure in conjunction with the accompanying drawings, which are schematic diagrams of the present disclosure and are not necessarily drawn to scale. Some of the block diagrams shown in the accompanying drawings may be functional entities, which do not necessarily correspond to physically or logically independent entities. These functional entities can be implemented in software form, or in hardware modules or integrated circuits, or in networks, processors or microcontrollers. The implementation method can be implemented in a variety of forms and should not be construed as being limited to the examples set forth herein. The features, structures or characteristics described in the present disclosure may be combined in one or more implementations in any suitable manner. In the following description, many specific details are provided to provide a full description of the implementation methods of the present disclosure. However, those skilled in the art should be aware that one or more specific details may be omitted when implementing the technical solution of the present disclosure, or one or more specific details may be replaced by other methods, components, devices, steps, etc.

[0042] In the related art, during the fatigue life test of the locomotive bogie structure, if you want to obtain the fatigue life of the measuring point, the tester needs to manually perform a series of operations such as cleaning the measuring point, marking, judging whether the strain gauge is consistent with the principal stress direction, pasting the strain gauge, exhausting the pasted strain gauge, and fixing it, in order to complete the data collection of the measuring point based on the strain gauge. In addition, the tester is also required to manually weld the power supply / signal cable of the strain gauge to the strain gauge, and arrange a longer cable along the locomotive structure, such as a 3-meter-long cable, so that the data processing software can obtain the data of the measuring point based on the cable and process the data to obtain the fatigue life of the measuring point.

[0043] This method not only takes a long time to collect data, but also takes a long time to transmit data, and places high demands on testers, which results in low efficiency in detecting the fatigue life of the measuring point.

[0044] In view of one or more of the above problems, an exemplary embodiment of the present disclosure provides a fatigue life test system. Since the data acquisition module in the fatigue life test system includes a sensor submodule for collecting data of the point to be tested, there is no need for the tester to manually perform a series of operations. The sensor included in the sensor submodule can be used to directly detect the change signal of the surface of the point to be tested during the force process, thereby shortening the arrangement time of the acquisition equipment for arranging and collecting data of the point to be tested, and improving the collection efficiency of the data of the point to be tested. In addition, since the sensor can directly send the change signal to the data transmission module in the fatigue life test system, the fatigue life test module in the fatigue life test system can receive the change signal transmitted based on the wireless method, perform fatigue life calculation on the change signal, and output the corresponding calculation result. In other words, in the embodiment of the present disclosure, there is no need for the tester to arrange the cable for the transmission of the change signal, which further shortens the data transmission time and improves the test efficiency of the entire fatigue life test system.

[0045] The fatigue life test system provided in the embodiment of the present disclosure can be applied to any business scenario of an adsorbable object that needs to be tested for fatigue life. The object may be, for example, a locomotive bogie load-bearing component, an automobile component, or an aircraft component, which is not limited in the embodiment of the present disclosure.

[0046] See also Figure 1 , Figure 1 A system architecture diagram of a fatigue life test system in this exemplary embodiment is shown. The fatigue life test system 100 includes a data acquisition module 110, a data transmission module 120, and a fatigue life test module 130, wherein: the data acquisition module 110 includes a sensor submodule for collecting data of the point to be tested; the sensor submodule includes a sensor, the sensor is used to detect the change signal of the surface of the point to be tested during the force process, and send the change signal to the data transmission module 120; the fatigue life test module 130 is used to calculate the fatigue life of the change signal transmitted by the data transmission module 120, and output the fatigue life information of the point to be tested.

[0047] In the disclosed embodiment, since the data acquisition module in the fatigue life test system includes a sensor submodule for collecting data of the point to be tested, there is no need for the tester to manually perform a series of operations. The change signal of the surface of the point to be tested during the force process can be detected directly based on the sensor included in the sensor submodule, thereby shortening the layout time of the collection equipment for collecting data of the point to be tested and improving the collection efficiency of the data of the point to be tested. In addition, since the sensor can directly send the change signal to the data transmission module in the fatigue life test system, the fatigue life test module in the fatigue life test system can receive the change signal based on wireless transmission, perform fatigue life calculation on the change signal, and output the corresponding calculation result. In other words, in the disclosed embodiment, there is no need for the tester to arrange cables for the transmission of the change signal, which further shortens the data transmission time and improves the test efficiency of the entire fatigue life test system.

[0048] See also Figure 1 , Figure 2 A system architecture diagram of a fatigue life test system in this exemplary embodiment is shown. Considering the problem of powering the data acquisition module 110, the fatigue life test system 100 also includes a wireless power supply module 140. It can be seen that in an optional design, the data acquisition module 110 and the data transmission module 120 can be set as one body, and the change signal collected by the data acquisition module 110 can be sent to the data transmission module 120 through a short cable (for example, 10 cm), that is, a cable for transmitting the change signal is arranged between the data acquisition module 110 and the data transmission module 120. In this way, compared with the data transmission scheme in the related art, there is no need to deploy large-area and long-length cables and pre-arrangement design and other operations, which not only shortens the data transmission time, but also reduces the loss of data transmission, and facilitates efficient data transmission. That is to say, the fatigue life test system 100 in the embodiment of the present disclosure includes a data acquisition module 110, a data transmission module 120, a fatigue life test module 130 and a wireless power supply module 140. In this way, it is possible to avoid the situation where the data acquisition module 1100 in the fatigue life test system 100 cannot collect data or collect data for too long due to the rapid decrease in battery capacity in cold areas, thereby shortening the data collection time of the fatigue life test system 100.

[0049] The following is combined with Figure 3-6 Each module of the fatigue life testing system 100 provided in the embodiment of the present disclosure is introduced in detail.

[0050] See also Figure 3 , Figure 3A schematic diagram of a data acquisition module 110 in this exemplary embodiment is shown. Optionally, the data acquisition unit 110 may include a sensor submodule 1101, the sensor submodule 1101 includes a housing 11011, an adsorbable head 11012, and a sensor 11013, wherein a first end of the housing 11011 is connected to the adsorbable head 11012, and a second end of the housing 11011 is connected to a cable or is provided with a cable outlet hole for leading out the cable.

[0051] In the embodiment of the present disclosure, the housing 11011 is used to protect and fix the sensor 11013 .

[0052] In a possible design, the housing 11011 may be in various shapes, such as a square, a rectangle, or a cylinder. Figure 3 As shown, this is not limited in the embodiments of the present disclosure.

[0053] In one possible design, the shell 11011 can be made of various lightweight and high-strength materials, such as aluminum alloy, titanium alloy, carbon fiber, magnesium alloy, and mineral wool, etc., which is not limited in the embodiments of the present disclosure.

[0054] In the disclosed embodiment, the adsorbable head 11012 is used to adsorb the sensor submodule 1101 to the object corresponding to the point to be measured. Figure 4 , Figure 4 It is a schematic diagram of adsorbing the sensor submodule 1101 onto the object corresponding to the point to be measured.

[0055] In one possible design, the shape of the adsorbable head 11012 is adapted to the shape of the housing 11011. Figure 2 As shown, when the shell 11011 is cylindrical, the adsorbable head 11012 is a ring structure.

[0056] In a possible design, the adsorbable head 11012 is a strong magnetic adsorption head, which includes at least two strong magnets, and the at least two strong magnets are arranged in a preset manner. The preset manner is, for example, a Halbach array manner, and of course, it can also be other arrangements that can maximize the magnetic attraction of the strong magnetic adsorption head 11012, which is not limited in the embodiments of the present disclosure.

[0057] In a possible design, the adsorbable head 11012 is an adhesive adsorbable head, which includes a first part for adhering to the point to be measured and a second part for adhering to the housing. Considering that in some cases, the vibration of the object to be measured may cause resonance of the sensor submodule, thereby reducing the test accuracy, the adhesive adsorbable head can be set as a disposable adapter head connected to the housing 11011, so that the adhesive adsorbable head can be attached to the surface of the point to be measured using instant adhesive, and can be unscrewed and discarded after use.

[0058] In the embodiment of the present disclosure, the sensor 11013 is capable of detecting change signals of the change conditions of the surface within the sensor's field of view (i.e., the measured point) during the force process, and returning the measured change signals to the data transmission module 120 via a cable.

[0059] In a possible design, the sensor 11013 may be configured as a sensor array, which includes at least four sensors. For example, the sensor array includes four sensors, or Figure 3 The 9 sensors shown are not limited in the embodiments of the present disclosure. That is, the number of displacement sensors in each sensor 11013 in the embodiments of the present disclosure should be set to facilitate the use of interpolation when determining the displacement gradient later, so as to more accurately determine the stress information.

[0060] In addition, the arrangement of multiple displacement sensors in the sensor array can be in a variety of ways, for example, different sensors have different projection positions on the surface of the measured point along a preset pattern, wherein the preset pattern is, for example, that the displacement sensors inside the sensor are arranged in a matrix of 3*3, 4*4 or other shapes that are convenient for data processing. Of course, other arrangements may also be possible, which is not limited to this in the embodiments of the present disclosure.

[0061] In one possible design, the sensors included in the sensor array may be displacement sensors, position sensors, or other sensors that detect changes in the surface under force within the sensor's field of view, which is not limited in the embodiments of the present disclosure.

[0062] It can be seen that in the disclosed embodiment, a miniature non-contact position measurement sensor is used, which integrates an optical position sensor array, and can obtain the strain value of the measuring point by identifying the small displacement changes of the surface in the test field of view. The head of the sensor submodule uses a strong magnet arranged in a Halbach array, which can be reliably adsorbed on the ferromagnetic material being measured. This method eliminates the traditional strain gauge pasting and arrangement method, and can quickly arrange the sensor. In addition, the strain obtained by this method can naturally know the main strain direction of the measured point, which overcomes the problem that the traditional unidirectional strain gauge must be consistent with the main stress direction when pasting, and improves the collection efficiency during data collection.

[0063] In the embodiments of the present disclosure, see Figure 5 The data transmission module 120 includes a wireless data transmission submodule 1201, which is connected to the sensor submodule 1101 through a cable to receive a change signal of the fluctuation change condition of the surface of the measured point during the force process collected by the sensor submodule 1101.

[0064] In the disclosed embodiment, the fatigue life test module 130 is used to calculate the fatigue life of the change signal transmitted by the data transmission module 120, and output the fatigue life information of the measured point. That is to say, the data transmission module 120 sends the change signal to the fatigue life test module 130 by wireless transmission. Compared with the data transmission scheme in the related technology, this method does not require the test personnel to manually deploy large-area and long-length cables and pre-design the wiring, etc., which reduces the time of data transmission, thereby improving the test efficiency of the fatigue life test system. In addition, on the basis of reducing the operation and deployment of the test personnel, that is, reducing the manpower and material costs, it also reduces the errors caused by manual processing, thereby improving the test accuracy of the fatigue life test system, providing a good implementation basis for the subsequent processing of the objects corresponding to the measured points, and improving the user experience.

[0065] See also Figure 6 , Figure 6 1 is an optional structural diagram of the wireless power supply module 140. The wireless power supply module 140 includes: a current conditioning submodule 1401 for converting alternating current into direct current, a microwave transmitting submodule 1402 for converting direct current into microwaves and transmitting microwaves, a microwave receiving submodule 1403 for receiving microwaves and transmitting electric energy to power the sensor 1101, and a microwave relay submodule 1404 for adjusting the direction of electric energy transmission.

[0066] Among them, the current conditioning submodule 1401 rectifies and conditions the 220V alternating current on the vehicle and converts it into high-purity direct current. The microwave transmitting submodule 1402 converts direct current power into microwave signals and transmits the microwave signals through the microwave transmitting antenna. The microwave relay submodule 1404 receives the microwave signal of the previous link and converts the transmission direction. The microwave relay submodule 1404 can be arranged on the structure under test. When the microwave receiving module 1403 is far away from the microwave transmitting module 1402 or is not in the direct transmission direction of the microwave transmitting module 1402, multiple microwave relay submodules 1404 can be used to form a power supply link system to change the direction of power transmission to achieve continuous transmission of microwave signals. The microwave receiving submodule 1403 has a receiving antenna that can receive microwaves carrying power transmitted by the previous link. The module has a converter inside that can convert microwaves into power of the specifications required by the sensor to achieve the purpose of wireless transmission of power. Optionally, the microwave receiving submodule 1403 has several power output interfaces that can power multiple displacement sensors at the same time.

[0067] In one possible design, considering the problem of powering the sensor 1101, the fatigue life test system can also be powered by the principle of laser wireless power transmission, that is, using electrical energy to emit a laser, propagating the laser along a relay link through a tracking and aiming system, and using a photovoltaic array to convert the laser's light energy into electrical energy, thereby achieving the purpose of powering the sensor 1101.

[0068] It can be seen that, since the data acquisition module in the fatigue life test system includes a sensor submodule for collecting data of the points to be tested, there is no need for the tester to manually perform a series of operations, and the change signal of the surface of the points to be tested during the force process can be directly detected based on the sensor included in the sensor submodule, thereby shortening the layout time of the collection equipment for arranging and collecting data of the points to be tested, and improving the collection efficiency of the data of the points to be tested. In addition, since the sensor can directly send the change signal to the data transmission module in the fatigue life test system through the cable, the fatigue life test module in the fatigue life test system can receive the change signal based on wireless transmission, and perform fatigue life calculation on the change signal, and output the corresponding calculation result. In other words, in the embodiment of the present disclosure, there is no need for the tester to arrange the cable for the transmission of the change signal, which further shortens the data transmission time, thereby improving the test efficiency of the entire fatigue life test system.

[0069] In the embodiment of the present disclosure, after introducing the fatigue life testing system 100, the fatigue life testing method performed by using the fatigue life testing system 100 is described below. Figure 7 .

[0070] Step 701: Determine the displacement information corresponding to the change signal collected by the sensor.

[0071] Step 702: Determine the stress information corresponding to the point to be measured according to the displacement information.

[0072] In a possible implementation, stress information corresponding to the point to be measured is determined based on the displacement information, including: determining the displacement gradient corresponding to the point to be measured based on the displacement information; determining the stress value and stress direction based on the obtained displacement gradients and the material properties of the object corresponding to the point to be measured, so as to determine the stress information corresponding to the point to be measured.

[0073] The following describes the process of specifically determining the stress information corresponding to the point to be measured.

[0074] Assume that the sensor has Figure 8 The displacement sensor arrangement shown in the figure, that is, each sensor has 9 displacement sensors forming a 3*3 array, so that each sensor can collect the material surface conditions at 9 positions within the field of view. Fig. 9 As shown, Fig. 9 The dashed line frame shows the measured surface before deformation, the solid line frame shows the measured surface after deformation due to force, and u1~u9 are the normal displacement changes of each acquisition point.

[0075] Assuming that the installation position of the sensor is recorded as point P, for the convenience of calculation, the surface normal displacement data of each displacement sensor collection point in the field of view of the sensor is expressed in the form of a matrix, for example, see formula (1), recorded as U.

[0076]

[0077] Wherein, ui is the normal displacement of the i-th sensor measuring point, and the normal displacement is relative to the initial surface of the measured point, indicating the degree of bulge or depression after deformation.

[0078] In order to calculate the strain, it is necessary to know the rate of change of displacement on the surface of the measured point, that is, the displacement gradient. In order to make full use of the displacement information of the 9 points, the weighted central difference method or the quadratic interpolation method can be used to estimate the displacement gradient. For example, by using quadratic interpolation processing on the rate of change of displacement, the displacement field corresponding to point P can be fitted through all 9 points around point P.

[0079] Assume that a quadratic polynomial is used to fit the displacement in the local area of ​​point P, as shown in formula (2).

[0080] u(x,y)=a0+a1x+a2y+a3x 2 +a4y 2 +a5xy formula (2).

[0081] Among them, x and y are coordinate systems centered on point P, and a0~a5 are unknown coefficients.

[0082] Specifically, by fitting the normal displacement data of the surrounding 9 points, the aforementioned unknown coefficients a0 to a5 can be solved to obtain the fitted displacement field. After obtaining the fitted displacement field, the displacement gradient at point P can be calculated based on the fitted displacement field.

[0083] The following describes the process of calculating the displacement gradient at point P based on the fitted displacement field:

[0084] First, refer to formula (3) to calculate the partial derivatives of the quadratic polynomial u(x,y) with respect to x and y:

[0085]

[0086] Then, referring to formula (4), the gradient is calculated at point P (i.e., x=0, y=0):

[0087]

[0088] Furthermore, the tangential stress at point P is the sum of the displacement gradients along the surface direction. Therefore, referring to formula (5), the tangential stress at point P can be determined based on the sum of the displacement gradients:

[0089]

[0090] Therefore, we can get ∈ tan , P =a1+a2. Furthermore, the stress at point P can be further calculated by combining the material properties of the material of the object corresponding to the point to be measured.

[0091] For example, assuming that the material of the object corresponding to the point to be measured is steel, the elastic modulus of the material is represented by E, and the Poisson's ratio of the material is represented by ν. Within the linear elastic range, the stress at point P can be further calculated based on the following formula (6):

[0092] σ tan,P =E*∈ tan，P Formula (6).

[0093] Furthermore, after obtaining the stress at point P, it is also necessary to obtain the direction of the strain at point P.

[0094] As shown in the previous formula (3), the gradient of the displacement field in the x and y directions has been calculated, and the direction of the displacement gradient needs to be calculated. The direction of the displacement gradient is determined according to the displacement gradient vector. Specifically, the direction of the tangential strain is parallel to the following vector, as shown in formula (7), which is expressed as:

[0095]

[0096] At point P, this gradient vector can be seen in formula (8):

[0097] g P =(a1,a2) Formula (8).

[0098] The gradient vector at point P can be normalized to a unit vector. Its expression is as follows:

[0099]

[0100] In order to more accurately express the direction of the tangential strain, the direction angle at point P can also be calculated. The direction angle is defined as the angle θ relative to the x-axis and can be determined based on formula (10):

[0101]

[0102] It should be noted that the aforementioned x-axis is determined by the installation position of the sensor, for example, see Figure 5 To determine the installation location as shown Fig. 9 The x-axis and y-axis are shown.

[0103] Visible, see Fig.10 , the surface strain solution in the embodiment of the present disclosure refers to the following process: Assuming that the displacement sensor array in the embodiment of the present disclosure includes an optical displacement sensor, each sampling interval (e.g. Fig.10 The undulation change condition of the surface after force deformation and the surface before force (reference) in Δ1, Δ2, Δ3, Δ4) is obtained. Then the normal deformation condition of several detection array points in the measured field of view obtained by the sensor array in each sensor submodule is extracted, and the tangential deformation vector at the center position of the surface of the measured field of view is obtained according to the deformed surface topography through mathematical calculation, so as to obtain the stress information of the point. This method can easily obtain the direction and size of the principal strain. Specifically, since the sensor array in the sensor submodule is small in size, more detection array points can be arranged in the measured field of view, so the deformation condition of the surface of the measured field of view can be known more comprehensively. In addition, since the sensor array is insensitive to the electromagnetic environment, insensitive to temperature changes, and the sensor array has a high accuracy in measuring normal deformation, and supports a high sampling rate, it can adapt to the fatigue test of components under high-frequency dynamic action, and provide a good implementation basis for the accurate collection of data of the fatigue test system, thereby improving the test accuracy of the fatigue life test system to a certain extent.

[0104] Step 703: Clean the stress information corresponding to the measured point to obtain processed stress information.

[0105] In the disclosed embodiment, data cleaning is performed on the stress information corresponding to the measured point, which refers to data processing of the surface strain data of a channel that has been solved to remove non-ideal conditions of the time series data (such as zero drift, burrs, sensor failure, etc.), and filtering is performed to obtain the processed stress information.

[0106] In a possible implementation, an artificial intelligence (AI) model trained with big data can be used to accurately identify invalid data in the collected time series data, such as burrs, zero drift, sensor failure, etc., and remove or repair these defective data; in subsequent processing, the AI ​​model can select appropriate filtering parameters to process the collected time series data, so as to obtain a more accurate fatigue life solution result. In addition, the time series data can be further analyzed in the frequency domain to obtain the results in the frequency domain. The AI ​​model can select appropriate parameters (such as the type and range of the window function, etc.) for processing, providing a good implementation basis for other processing. In order to speed up the data processing speed and reduce the system burden, a possible processing method is: set the sampling interval to a preset time length, which is, for example, 2 minutes, 3 minutes or 5 minutes, etc., which is not limited in the embodiment of the present disclosure, and then use the AI ​​model to process this data time series, while the data collection of the sensor is still in progress. In other words, the two steps of processing the data time series and collecting the sensor data can be carried out in parallel and alternately, so as to improve the data processing efficiency and reduce the system burden.

[0107] Step 704: Determine fatigue life information of the measured point according to the processed stress information and the stress-life SN curve of the object corresponding to the measured point.

[0108] In the disclosed embodiment, fatigue life calculation refers to calculating the fatigue life of the material structure under the current load by performing rain flow counting on the data based on the cleaning of specified time series data and combining it with the SN curve of the material being tested, thereby obtaining the fatigue life information of the tested point.

[0109] For example, see Fig.11 As shown, Fig.11 FIG. 1 is a schematic diagram of a process for solving fatigue life information of a measured point in an embodiment of the present disclosure. Fig.11 The process shown can quickly obtain the fatigue life estimation value of the measured point, so as to perform corresponding processing on the object corresponding to the measured point based on the value.

[0110] It should be understood that the present disclosure is not limited to the specific method steps or structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from the scope thereof. Those skilled in the art will easily think of other embodiments based on the specific embodiments provided by the present disclosure. Therefore, the specific embodiments provided by the present disclosure are only exemplary, and the scope and spirit of the present disclosure are indicated by the claims, and any variations, uses or adaptive changes of the present disclosure should be covered, which follow the general principles of the present disclosure and include common knowledge or customary technical means in the technical field that are not disclosed in the present disclosure.

Claims

1. A fatigue life testing system, characterized in that: The system includes a data acquisition module, a data transmission module and a fatigue life test module, wherein: The data acquisition module includes a sensor submodule for collecting data of the point to be measured; the sensor submodule includes a sensor, and the sensor is used to detect the change signal of the surface of the point to be measured during the force process, and send the change signal to the data transmission module; The fatigue life test module is used to perform fatigue life calculation on the change signal transmitted by the data transmission module, and output fatigue life information of the measured point.

2. The system according to claim 1, characterized in that A cable for transmitting the change signal is arranged between the data acquisition module and the data transmission module; the sensor submodule also includes a shell and an adsorbable head, and the adsorbable head is used to adsorb the sensor submodule to the object corresponding to the point to be measured; the first end of the shell is connected to the adsorbable head, and the second end of the shell is connected to the cable or is provided with an outlet hole for leading out the cable.

3. The system according to claim 2, characterized in that The housing is cylindrical and is used to protect and fix the sensor.

4. The system according to claim 3, characterized in that The adsorbable head is a ring structure.

5. The system according to claim 2, characterized in that The adsorbable head is a strong magnetic adsorption head, and the strong magnetic adsorption head includes at least two strong magnets, and the at least two strong magnets are arranged in a preset manner.

6. The system according to claim 2, characterized in that The adsorbable head is a sticky adsorption head, and the sticky adsorption head comprises a first part for sticking to the point to be measured and a second part for sticking to the shell.

7. The system according to claim 1, characterized in that The sensor is a sensor array, and the sensor array includes at least four sensors, wherein different sensors have different projection positions on the surface of the point to be measured along a preset pattern.

8. The system according to any one of claims 1 to 7, characterized in that: The system also includes a wireless power supply module, which includes: a current conditioning submodule for converting alternating current into direct current, a microwave transmitting submodule for converting direct current into microwaves and emitting microwaves, a microwave relay submodule for adjusting the direction of power transmission, and a microwave receiving submodule for receiving microwaves and transmitting power to power the sensor.

9. A fatigue testing method, characterized in that: Applied to the fatigue life testing system according to any one of claims 1 to 8, the method comprises: Determine the displacement information corresponding to the change signal collected by the sensor; Determine stress information corresponding to the point to be measured according to the displacement information; Performing data cleaning on the stress information corresponding to the points to be measured to obtain processed stress information; The fatigue life information of the measured point is determined according to the processed stress information and the stress-life SN curve of the object corresponding to the measured point.

10. The method according to claim 9, characterized in that Determining stress information corresponding to the point to be measured according to the displacement information includes: Determine the displacement gradient corresponding to the measured point according to the displacement information; The stress value and stress direction are determined according to the obtained displacement gradient and the material properties of the object corresponding to the measured point, so as to determine the stress information corresponding to the measured point.

Images