Vehicle body fatigue life test method, computer storage medium and electronic equipment

Abstract

The present invention provides a vehicle fatigue life test method, a computer storage medium and an electronic device. The vehicle fatigue life test method comprises: S1, selecting multiple detection sites on the test vehicle, setting a first detection piece at each detection site, loading the test vehicle on the test bench, obtaining multiple vertical stresses, and obtaining a reference point; S2, setting a second detection piece at the reference point of the test vehicle, applying a test longitudinal load to the test vehicle, obtaining a test longitudinal stress, and a relationship between the test longitudinal load and the test longitudinal stress; S3, setting a second detection piece at the reference point of the vehicle to be tested, obtaining multiple longitudinal stresses to be tested, and obtaining multiple longitudinal loads to be tested according to the relationship and the multiple longitudinal stresses to be tested; S4, obtaining a time domain signal according to the number of cycles of the multiple longitudinal loads to be tested and the multiple longitudinal stresses to be tested; S5, performing a fatigue test on the test vehicle. The problem that the fatigue life test method cannot meet the demand can be solved.

Description

Technical Field

[0001] The present invention relates to the technical field of trains, and in particular to a vehicle body fatigue life testing method, a computer storage medium and an electronic device. Background Art

[0002] The longitudinal load in the actual operation of railway freight cars is the main cause of fatigue damage to the car body. Internationally, the North American Association of Railroads (AAR) locomotive standard "Fatigue Design of New Freight Cars" obtained the longitudinal load spectra of 7 specific freight car models from actual line measurements. Currently, railway freight cars exported from my country usually use the load spectra provided by the AAR standard for fatigue analysis. my country's research on railway freight car load spectra has made certain progress since the late 1980s. These vehicle longitudinal load spectrum data obtained from the statistics of actual test load data are widely used in car body fatigue simulation calculations and fatigue simulation of couplers. Longitudinal loading conditions are the main conditions of car body fatigue tests and are crucial to the assessment of car body fatigue reliability. Therefore, it is very critical to use railway freight car body fatigue test benches and longitudinal load spectrum data to carry out research on railway freight car body accelerated fatigue test technology.

[0003] At present, both the vehicle longitudinal load spectrum provided by the AAR standard and the longitudinal load spectrum obtained by domestic testing use force measuring coupler sensors to conduct longitudinal load tests. The disadvantage of this method is that the coupler load can only be transmitted to the car body through the buffer, and there is a difference between the tested coupler longitudinal load and the actual longitudinal load borne by the car body.

[0004] However, there is currently no method to use the statistical data of the longitudinal load spectrum of railway freight cars to conduct longitudinal accelerated fatigue tests on full-size railway freight car bodies. Summary of the invention

[0005] The present invention provides a vehicle body fatigue life test method, a computer storage medium and an electronic device to solve the problem that the fatigue life test method in the related art cannot meet the demand.

[0006] According to one aspect of the present invention, a vehicle body fatigue life test method is provided, and the vehicle body fatigue life test method comprises: S1, selecting multiple detection sites on the test vehicle body, setting a first detection piece at each detection site, loading the test vehicle body on the test bench, applying a vertical load to the test vehicle body to obtain multiple vertical stresses detected by multiple first detection pieces, obtaining the smallest one of the multiple vertical stresses, and using the detection site where the first detection piece is located as a reference point; S2, setting a second detection piece at the reference point of the test vehicle body, applying a test longitudinal load to the test vehicle body, and obtaining a test longitudinal stress. Stress, using the test longitudinal load and the test longitudinal stress, obtain the relationship between the test longitudinal load and the test longitudinal stress; S3, obtain the marked points of the vehicle body to be tested according to the marked points of the test vehicle body, set a second detection piece at the marked points of the vehicle body to be tested, obtain multiple longitudinal stresses to be tested, and obtain multiple longitudinal loads to be tested according to the relationship and the multiple longitudinal stresses to be tested; S4, obtain the number of cycles of the multiple longitudinal stresses to be tested, and obtain the time domain signal according to the number of cycles of the multiple longitudinal loads to be tested and the multiple longitudinal stresses to be tested; S5, load the time domain signal on the test vehicle body, and perform a fatigue test on the test vehicle body.

[0007] Further, in step S4, the step of obtaining a time domain signal according to the number of cycles of the plurality of longitudinal loads to be measured and the plurality of longitudinal stresses to be measured includes: S41, dividing the longitudinal loads to be measured into A levels, determining the converted longitudinal load in each level, and calculating the converted longitudinal load according to the formula The number of cycles of the multiple longitudinal loads to be measured and the multiple longitudinal stresses to be measured are equivalently converted to obtain the number of cycles corresponding to the multiple converted longitudinal loads, where F a is the longitudinal load to be tested, N a is the number of cycles of the longitudinal load to be tested, F b To convert the longitudinal load, N b is the number of cycles corresponding to the converted longitudinal load, and m is the reverse slope of the SN double logarithmic curve; S42, obtaining a time domain signal according to multiple converted longitudinal loads and the number of cycles of multiple converted longitudinal loads, multiple unconverted longitudinal loads to be measured, and multiple unconverted longitudinal stresses to be measured.

[0008] Further, in step S41, the step of dividing the longitudinal load to be measured into A levels includes: S411, using the rain flow counting method, performing graded statistics on the number of cycles of multiple longitudinal loads to be measured and multiple longitudinal stresses to be measured to obtain a graded load spectrum; S412, dividing the graded load spectrum into A levels.

[0009] Furthermore, a test center beam is provided on the test vehicle body, and the test center beam includes two corresponding test webs. In step S1, a plurality of detection sites are selected on the test vehicle body, and the step of setting a first detection piece at each detection site includes: S11, selecting a plurality of detection sites on the two test webs in the horizontal direction, setting a first detection piece at each detection site, and arranging the plurality of first detection pieces in sequence in the vertical direction.

[0010] Further, in step S2, a second detection piece is set at a marked position point of the test vehicle body, and a test longitudinal load is applied to the test vehicle body. The step of obtaining the test longitudinal stress includes: a second detection piece extending vertically is set at a marked position point of each test web, the first detection piece and the second detection piece are formed into a Wheatstone bridge, a test longitudinal load is applied to the test vehicle body, and the test longitudinal stress is obtained using the Wheatstone bridge.

[0011] Furthermore, a center beam to be tested is arranged on the vehicle body to be tested, and the center beam to be tested includes two corresponding webs to be tested. In step S3, a second detection piece is arranged at a marked position point of the vehicle body to be tested, and the step of obtaining multiple longitudinal stresses to be tested includes: a first detection piece and a second detection piece are arranged at a marked position point of each web to be tested, the first detection piece and the second detection piece are formed into a Wheatstone bridge, and multiple longitudinal stresses to be tested are obtained using the Wheatstone bridge.

[0012] Further, in step S1, applying a vertical load to the test vehicle body to obtain a plurality of vertical stresses detected by a plurality of first detection members includes: S12, adjusting the vertical load to obtain a plurality of vertical stresses detected by a plurality of first detection members under different vertical loads.

[0013] Further, in step S4, the time domain signal is a sinusoidal time domain signal.

[0014] According to another aspect of the present invention, a computer storage medium is provided, the computer storage medium is used to store a program, wherein when the program is run, the device where the computer storage medium is located is controlled to execute the vehicle body fatigue life test method provided above.

[0015] According to another aspect of the present invention, an electronic device is provided, including a memory and a processor, wherein a computer program is stored in the memory, and the processor is configured to execute the vehicle body fatigue life test method provided above through the computer program.

[0016] By applying the technical solution of the present invention, multiple detection sites are selected on the test vehicle body so that the first detection piece can be set at the corresponding detection sites, and the test vehicle body is loaded on the test bench, and a vertical load can be applied to the test vehicle body, and the first detection piece is used to detect multiple vertical stresses of the vehicle body under the vertical load. By comparing the multiple vertical stresses, the smallest one of the multiple vertical stresses can be obtained, and then the detection site where the first detection piece of the vertical stress is measured is used as the calibration point. A second detection piece is set at the calibration point of the test vehicle body, and a test longitudinal load is applied to the test vehicle body, and then the test longitudinal stress can be measured, and then the relationship between the test longitudinal load and the test longitudinal stress can be obtained. The calibration points of the vehicle body to be tested are obtained according to the calibration points of the test vehicle body, and the vehicle body to be tested is subjected to actual road testing. The second detection piece is set at the calibration points of the vehicle body to be tested, and then multiple longitudinal stresses to be tested can be obtained. Multiple longitudinal loads to be tested can be obtained by using the relationship and the longitudinal stresses to be tested, and then the cycles of the multiple longitudinal stresses to be tested are obtained. At this time, the number of cycles of the multiple longitudinal loads to be tested and the multiple longitudinal stresses to be tested can be compiled into a time domain signal. By loading the time domain signal on the test vehicle body, a fatigue test of the test vehicle body can be performed. By adopting the above test method, by loading the time domain signal on the test vehicle body, a longitudinal acceleration fatigue test can be performed on the vehicle body, thereby obtaining a more accurate fatigue test result. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0018] Figure 1 A flow chart of a vehicle body fatigue life test method provided in an embodiment of the present invention is shown;

[0019] Figure 2 A schematic diagram showing the structure of the first detection member being installed on the vehicle body;

[0020] Figure 3 It shows a schematic diagram of the structure in which the first detection member and the second detection member are installed on the vehicle body;

[0021] Figure 4 A schematic diagram showing the structure of the first detection member being installed on the vehicle body;

[0022] Figure 5 A circuit diagram of a Wheatstone bridge according to a vehicle body fatigue life test method provided by an embodiment of the present invention is shown;

[0023] Figure 6 It shows a sinusoidal time domain signal diagram after longitudinal load equivalent provided by a specific embodiment of the present invention;

[0024] Figure 7 A comparison diagram of the longitudinal loading signal of the test vehicle body and the feedback signal of the test bench provided according to a specific embodiment of the present invention is shown.

[0025] The above drawings include the following reference numerals:

[0026] 10. The first test piece;

[0027] 20. Second test piece;

[0028] 30. Test the belly plate. DETAILED DESCRIPTION

[0029] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] like Figures 1 to 5 As shown, an embodiment of the present invention provides a vehicle body fatigue life test method, which includes: S1, selecting multiple detection sites on the test vehicle body, setting a first detection member 10 at each detection site, loading the test vehicle body on the test bench, applying a vertical load to the test vehicle body to obtain multiple vertical stresses detected by the multiple first detection members 10, obtaining the smallest one of the multiple vertical stresses, and using the detection site where the first detection member 10 is located as a reference point; S2, setting a second detection member 20 at the reference point of the test vehicle body, applying a test longitudinal load to the test vehicle body, and obtaining a test longitudinal load. longitudinal stress, using the test longitudinal load and the test longitudinal stress to obtain the relationship between the test longitudinal load and the test longitudinal stress; S3, obtaining the calibration points of the vehicle body to be tested according to the calibration points of the test vehicle body, setting a second detection piece 20 at the calibration points of the vehicle body to be tested, obtaining multiple longitudinal stresses to be tested, and obtaining multiple longitudinal loads to be tested according to the relationship and the multiple longitudinal stresses to be tested; S4, obtaining the number of cycles of the multiple longitudinal stresses to be tested, and obtaining the time domain signal according to the number of cycles of the multiple longitudinal loads to be tested and the multiple longitudinal stresses to be tested; S5, loading the time domain signal on the test vehicle body to perform a fatigue test on the test vehicle body.

[0031] By applying the technical solution of the present invention, multiple detection sites are selected on the test vehicle body so that the first detection member 10 can be set at the corresponding detection sites. The test vehicle body is loaded on the test bench, a vertical load can be applied to the test vehicle body, and the first detection member 10 is used to detect multiple vertical stresses of the vehicle body under the vertical load. By comparing the multiple vertical stresses, the smallest one of the multiple vertical stresses can be obtained, and then the detection site where the first detection member 10 of the measured vertical stress is located is used as the calibration point. The second detection member 20 is set at the calibration point of the test vehicle body, and a test longitudinal load is applied to the test vehicle body, so that the test longitudinal stress can be measured, and then the relationship between the test longitudinal load and the test longitudinal stress can be obtained. According to the marking points of the test vehicle body, the marking points of the vehicle body to be tested are obtained, and the vehicle body to be tested is subjected to actual road testing. A second detection member 20 is set at the marking points of the vehicle body to be tested, so that multiple longitudinal stresses to be tested can be obtained. Multiple longitudinal loads to be tested can be obtained by using the relationship and the longitudinal stress to be tested, and then the cycles of multiple longitudinal stresses to be tested are obtained. At this time, the time domain signal can be compiled according to the number of cycles of the multiple longitudinal loads to be tested and the multiple longitudinal stresses to be tested. The time domain signal is loaded on the test vehicle body, and a fatigue test of the test vehicle body can be carried out. By adopting the above-mentioned test method, by loading the time domain signal on the test vehicle body, a longitudinal accelerated fatigue test can be carried out on the vehicle body, so as to obtain more accurate fatigue test results.

[0032] Among them, in addition to bearing longitudinal loads, railway freight cars are also stimulated by the unevenness of the track to produce random vibrations when running on the line. The random vibrations are mainly composed of six rigid body movements such as floating, yaw, longitudinal expansion and contraction, shaking head, nodding and rolling, as well as elastic body vibrations such as vertical bending and torsional vibration. Under normal circumstances, the rigid body vibrations of yaw, shaking head and nodding contribute little to the stress of the vehicle body and are not considered. The influence of floating, rolling rigid body vibrations and elastic body vibrations such as vertical bending and torsion needs to be considered. In step S1, by applying a vertical load and using the first detection member 10 to obtain multiple vertical stresses at multiple detection sites, the detection site with the smallest vertical stress can be obtained, and then the influence of vertical vibration and vertical bending on the longitudinal accelerated fatigue test can be eliminated.

[0033] In this embodiment, the test vehicle body and the vehicle body to be tested are of the same model, and their structural performances are the same, and their calibration points can be selected at the same position.

[0034] It should be noted that, in step S3, by making the vehicle body to be tested perform an actual route test, load data under real road conditions can be obtained.

[0035] Wherein, for the vehicle body longitudinal load spectrum that has been obtained or the load spectrum data specified in the standard, the fatigue test can be directly performed using step S4 and step S5.

[0036] In step S4, the step of obtaining a time domain signal according to the number of cycles of the plurality of longitudinal loads to be measured and the plurality of longitudinal stresses to be measured includes: S41, dividing the longitudinal loads to be measured into A levels, determining the converted longitudinal load in each level, and calculating the converted longitudinal load according to the formula The number of cycles of the multiple longitudinal loads to be measured and the multiple longitudinal stresses to be measured are equivalently converted to obtain the number of cycles corresponding to the multiple converted longitudinal loads, where F a is the longitudinal load to be tested, N a is the number of cycles of the longitudinal load to be tested, F b To convert the longitudinal load, N b is the number of cycles corresponding to the converted longitudinal load, and m is the reverse slope of the SN double logarithmic curve; S42, a time domain signal is obtained according to multiple converted longitudinal loads and the number of cycles of multiple converted longitudinal loads, multiple unconverted longitudinal loads to be measured, and the number of cycles of multiple unconverted longitudinal stresses to be measured. By adopting the above test steps and using the above formula, the number of cycles of the longitudinal load to be measured and the corresponding longitudinal load to be measured can be equivalent to the number of cycles of the converted longitudinal load and the corresponding converted longitudinal load. In addition, the number of longitudinal loads to be measured can be reduced, and the longitudinal loads to be measured can be concentrated, so that a suitable time domain signal can be obtained.

[0037] It should be noted that the measured longitudinal load and its cycle number that need to be converted are small longitudinal load data that contribute little or no to the fatigue damage of the vehicle body. In order to make the fatigue test more accurate, the above-mentioned small longitudinal load data are equivalently converted to a larger longitudinal load and the corresponding number of cycles. After the conversion, the fatigue damage remains consistent, and thus a suitable time domain signal can be obtained.

[0038] The number of cycles of the longitudinal stress to be measured is the number of cycles of the longitudinal load to be measured.

[0039] In this embodiment, the specific value of the converted longitudinal load in each level is determined according to the range of the longitudinal load to be measured in each level. Generally, the median value of the range is taken as the converted longitudinal load.

[0040] In step S41, the step of dividing the longitudinal load to be measured into A levels includes: S411, using the rain flow counting method, performing graded statistics on the number of cycles of multiple longitudinal loads to be measured and multiple longitudinal stresses to be measured to obtain a graded load spectrum; S412, dividing the graded load spectrum into A levels. By adopting the above steps, the rain flow counting method can be used for statistical classification, and then the measured longitudinal loads to be measured and their number of cycles are counted to obtain a graded load spectrum, and then the grade division can be performed according to the graded load spectrum.

[0041] like Figure 2 and Figure 3As shown, a test center beam is provided on the test vehicle body, and the test center beam includes two corresponding test webs 30. In step S1, multiple detection sites are selected on the test vehicle body, and the step of setting a first detection piece 10 at each detection site includes: S11, multiple detection sites are selected on the two test webs 30 in the horizontal direction, a first detection piece 10 is set at each detection site, and multiple first detection pieces 10 are arranged in sequence in the vertical direction. With the above detection site setting, since the longitudinal tensile load acts on the front plate seat and the longitudinal compressive load acts on the rear plate seat during the actual driving of the vehicle body, the center beam part on the inner side of the vehicle body center plate can withstand both the longitudinal tensile load and the compressive load of the vehicle body. By setting the first detection piece 10 on both test webs 30, the longitudinal tensile load and the compressive load can be accurately measured.

[0042] In this embodiment, the first detection member 10 is a resistance strain gauge.

[0043] like Figures 2 to 4 As shown, in step S2, a second detection member 20 is set at a marked position of the test vehicle body, and a test longitudinal load is applied to the test vehicle body. The step of obtaining the test longitudinal stress includes: a second detection member 20 extending vertically is set at a marked position of each test web 30, the first detection member 10 and the second detection member 20 form a Wheatstone bridge, a test longitudinal load is applied to the test vehicle body, and the test longitudinal stress is obtained by using the Wheatstone bridge. By adopting the above steps, the Wheatstone bridge can eliminate the influence of torsion and rolling vibration, so that the result of the longitudinal load fatigue test is more accurate.

[0044] In this embodiment, the two first detection members 10 of the Wheatstone bridge are paired bridges, and the two second detection members 20 are paired bridges. Since the stress output on the webs on both sides is opposite under torsion and rolling vibration, after the full Wheatstone bridge is formed in the above manner, the stress caused by rolling and torsion can be offset.

[0045] The vehicle body to be tested is provided with a center beam to be tested, and the center beam to be tested includes two correspondingly arranged webs to be tested. In step S3, a second detection piece 20 is set at a marked position point of the vehicle body to be tested, and the step of obtaining a plurality of longitudinal stresses to be tested includes: a first detection piece 10 and a second detection piece 20 are set at a marked position point of each web to be tested, the first detection piece 10 and the second detection piece 20 are formed into a Wheatstone bridge, and a plurality of longitudinal stresses to be tested are obtained by using the Wheatstone bridge. By adopting the above steps, since the longitudinal tensile load acts on the front plate seat and the longitudinal compressive load acts on the rear plate seat during the actual driving of the vehicle body, the center beam part on the inner side of the vehicle body center plate can withstand both the longitudinal tensile load and the compressive load of the vehicle body. By setting the first detection piece 10 and the second detection piece 20 on both webs to be tested, the longitudinal tensile load and the compressive load can be accurately measured.

[0046] In step S1, a vertical load is applied to the test vehicle body to obtain a plurality of vertical stresses detected by the plurality of first detection members 10, including: S12, adjusting the vertical load to obtain a plurality of vertical stresses detected by the plurality of first detection members 10 under different vertical loads. By adjusting the vertical load, multiple vertical load loading tests can be performed, and then a plurality of vertical stresses can be obtained, and comparison can be made among the plurality of vertical stresses to obtain a calibration point, thereby making the test result more accurate.

[0047] In step S4, the time domain signal is a sinusoidal time domain signal. Using the above sinusoidal time domain signal can make the test result more accurate.

[0048] The following is analyzed in conjunction with specific embodiments:

[0049] like Figure 6 and Figure 7 As shown, taking the longitudinal load spectrum of a 110-ton high-side open car in the AAR standard as an example, its test mileage is 13,648 kilometers, and the total number of cycles is 1,341,332 times. The small load cycles account for a large proportion. Calculated at a loading frequency of 2 Hz, taking the full life cycle fatigue test of a railway freight car running 2.5 million kilometers as an example, the time to complete the longitudinal loading is about 4 years. Taking into account the technical feasibility and test economy of the accelerated fatigue test, in order to achieve the test purpose of accelerated fatigue, the small load data below 351 kN with a large number of cycles in the longitudinal load spectrum are equivalently converted into the data corresponding to the large load in the load spectrum according to the formula, and the fatigue damage remains consistent. The remaining cumulative frequency of the longitudinal load is 12,537 times. Calculated at a loading frequency of 2 Hz, the time to complete the longitudinal load loading is about 14 days. Considering the rationality and economy of the accelerated fatigue test, such a result is more in line with expectations. The sinusoidal loading signal of the longitudinal accelerated fatigue test of the vehicle body generated after the equivalent conversion is shown in Figure 6 Using the above longitudinal loading signal, the C80 aluminum alloy coal open car body longitudinal acceleration fatigue test was carried out. The fatigue test loading signal is basically consistent with the signal fed back by the test bench, as shown in Figure 7 As shown, the effect is good.

[0050] It should be noted that in order to reflect the comparison effect, the longitudinal load to be measured, which is counted by the rain flow counting method, is converted into equivalent form using the formula, and the number of cycles corresponding to the longitudinal load is converted into loading time according to the loading capacity of the test bench. For example, if the single loading time of a longitudinal load on the test bench is 1s, then the number of cycles corresponding to the longitudinal load converted into loading time is 1x the number of cycles.

[0051] Another embodiment of the present invention provides a computer storage medium, which is used to store a program, wherein when the program is running, the device where the computer storage medium is located is controlled to execute the vehicle fatigue life test method provided above. A plurality of detection sites are selected on the test vehicle body so that a first detection piece 10 can be set at the corresponding detection sites, and the test vehicle body is loaded on the test bench, a vertical load can be applied to the test vehicle body, and the first detection piece 10 is used to detect a plurality of vertical stresses of the vehicle body under the vertical load. By comparing the plurality of vertical stresses, the smallest one of the plurality of vertical stresses can be obtained, and then the detection site where the first detection piece 10 of the measured vertical stress is located is used as a marking point. A second detection piece 20 is set at the marking point of the test vehicle body, and a test longitudinal load is applied to the test vehicle body, so that the test longitudinal stress can be measured, and then the relationship between the test longitudinal load and the test longitudinal stress can be obtained. According to the marking points of the test vehicle body, the marking points of the vehicle body to be tested are obtained, and the vehicle body to be tested is subjected to actual road testing. A second detection member 20 is set at the marking points of the vehicle body to be tested, so that multiple longitudinal stresses to be tested can be obtained. Multiple longitudinal loads to be tested can be obtained by using the relationship and the longitudinal stress to be tested, and then the cycles of multiple longitudinal stresses to be tested are obtained. At this time, the time domain signal can be compiled according to the number of cycles of the multiple longitudinal loads to be tested and the multiple longitudinal stresses to be tested. The time domain signal is loaded on the test vehicle body, and a fatigue test of the test vehicle body can be carried out. By adopting the above-mentioned test method, by loading the time domain signal on the test vehicle body, a longitudinal accelerated fatigue test can be carried out on the vehicle body, so as to obtain more accurate fatigue test results.

[0052] Another embodiment of the present invention provides an electronic device, including a memory and a processor, wherein a computer program is stored in the memory, and the processor is configured to execute the vehicle fatigue life test method provided above through the computer program. A plurality of detection sites are selected on the test vehicle body, so that a first detection piece 10 can be set at the corresponding detection sites, and the test vehicle body is loaded on the test bench, so that a vertical load can be applied to the test vehicle body, and the first detection piece 10 is used to detect a plurality of vertical stresses of the vehicle body under the vertical load. By comparing the plurality of vertical stresses, the smallest one of the plurality of vertical stresses can be obtained, and then the detection site where the first detection piece 10 of the measured vertical stress is located is used as a marking point. A second detection piece 20 is set at the marking point of the test vehicle body, and a test longitudinal load is applied to the test vehicle body, so that the test longitudinal stress can be measured, and then the relationship between the test longitudinal load and the test longitudinal stress can be obtained. According to the marking points of the test vehicle body, the marking points of the vehicle body to be tested are obtained, and the vehicle body to be tested is subjected to actual road testing. A second detection member 20 is set at the marking points of the vehicle body to be tested, so that multiple longitudinal stresses to be tested can be obtained. Multiple longitudinal loads to be tested can be obtained by using the relationship and the longitudinal stress to be tested, and then the cycles of multiple longitudinal stresses to be tested are obtained. At this time, the time domain signal can be compiled according to the number of cycles of the multiple longitudinal loads to be tested and the multiple longitudinal stresses to be tested. The time domain signal is loaded on the test vehicle body, and a fatigue test of the test vehicle body can be carried out. By adopting the above-mentioned test method, by loading the time domain signal on the test vehicle body, a longitudinal accelerated fatigue test can be carried out on the vehicle body, so as to obtain more accurate fatigue test results.

[0053] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0054] Unless otherwise specifically stated, the relative arrangement, numerical expressions and numerical values ​​of the parts and steps set forth in these embodiments do not limit the scope of the present invention. Meanwhile, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to the actual proportional relationship. The technology, method and equipment known to those of ordinary skill in the relevant art may not be discussed in detail, but in appropriate cases, the technology, method and equipment should be considered as a part of the specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, and therefore, once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0055] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the devices or elements referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of the present invention. The directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.

[0056] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0057] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. If not otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the present invention.

[0058] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A vehicle body fatigue life test method, characterized in that: The vehicle body fatigue life test method comprises: S1. Select multiple detection sites on a test vehicle body, set a first detection member (10) at each detection site, load the test vehicle body on a test bench, apply a vertical load to the test vehicle body to obtain multiple vertical stresses detected by the multiple first detection members (10), obtain the smallest one of the multiple vertical stresses, and use the detection site where the first detection member (10) is located as a calibration point; S2, arranging a second detection member (20) at a marked position point of the test vehicle body, applying a test longitudinal load to the test vehicle body to obtain a test longitudinal stress, and using the test longitudinal load and the test longitudinal stress to obtain a relationship between the test longitudinal load and the test longitudinal stress; S3, obtaining the marked points of the vehicle body to be tested according to the marked points of the test vehicle body, setting the second detection member (20) at the marked points of the vehicle body to be tested, obtaining a plurality of longitudinal stresses to be tested, and obtaining a plurality of longitudinal loads to be tested according to the relationship and the plurality of longitudinal stresses to be tested; S4, obtaining a plurality of cycle numbers of the longitudinal stresses to be measured, and obtaining a time domain signal according to the plurality of longitudinal loads to be measured and the plurality of cycle numbers of the longitudinal stresses to be measured; S5. Load the time domain signal onto the test vehicle body to perform a fatigue test on the test vehicle body.

2. The vehicle body fatigue life test method according to claim 1, characterized in that: In step S4, the step of obtaining the time domain signal according to the number of cycles of the plurality of longitudinal loads to be measured and the plurality of longitudinal stresses to be measured comprises: S41, dividing the longitudinal load to be measured into A levels, determining the converted longitudinal load in each level, according to the formula The number of cycles of the plurality of longitudinal loads to be measured and the plurality of longitudinal stresses to be measured are equivalently converted to obtain the number of cycles corresponding to the plurality of converted longitudinal loads, wherein F a is the longitudinal load to be measured, N a is the number of cycles of the longitudinal load to be tested, F b To convert the longitudinal load, N b is the number of cycles corresponding to the converted longitudinal load, m is the reverse slope of the SN double logarithmic curve; S42, obtaining the time domain signal according to the plurality of converted longitudinal loads and the plurality of cycle numbers of the converted longitudinal loads, the plurality of unconverted longitudinal loads to be measured and the plurality of unconverted cycle numbers of the plurality of longitudinal stresses to be measured.

3. The vehicle body fatigue life test method according to claim 2, characterized in that: In step S41, the step of dividing the longitudinal load to be measured into A levels includes: S411, using a rain flow counting method, performing hierarchical statistics on the number of cycles of the plurality of longitudinal loads to be measured and the plurality of longitudinal stresses to be measured, so as to obtain a hierarchical load spectrum; S412, dividing the graded load spectrum into A grades.

4. The vehicle body fatigue life testing method according to claim 1, characterized in that: The test vehicle body is provided with a test center beam, the test center beam comprising two correspondingly arranged test webs (30), and in step S1, a plurality of the detection locations are selected on the test vehicle body, and the step of arranging the first detection member (10) at each of the detection locations comprises: S11, selecting a plurality of detection sites on the two test webs (30) in the transverse direction, setting the first detection member (10) at each detection site, and arranging the plurality of first detection members (10) in sequence in the vertical direction.

5. The vehicle body fatigue life testing method according to claim 4, characterized in that: In step S2, the second detection member (20) is arranged at a marked position point of the test vehicle body, and the test longitudinal load is applied to the test vehicle body. The step of obtaining the test longitudinal stress comprises: The second detection member (20) extending vertically is arranged at a marking point of each test web (30), the first detection member (10) and the second detection member (20) form a Wheatstone bridge, the test longitudinal load is applied to the test vehicle body, and the test longitudinal stress is obtained using the Wheatstone bridge.

6. The vehicle body fatigue life testing method according to claim 4, characterized in that: The vehicle body to be tested is provided with a center beam to be tested, and the center beam to be tested includes two correspondingly arranged webs to be tested. In step S3, the second detection member (20) is arranged at a marked position point of the vehicle body to be tested. The step of obtaining a plurality of longitudinal stresses to be tested includes: The first detection member (10) and the second detection member (20) are arranged at the marked position point of each web to be tested, the first detection member (10) and the second detection member (20) are combined into a Wheatstone bridge, and the plurality of longitudinal stresses to be tested are obtained using the Wheatstone bridge.

7. The vehicle body fatigue life testing method according to claim 1, characterized in that: In step S1, the step of applying a vertical load to the test vehicle body to obtain a plurality of vertical stresses detected by the first detection member (10) comprises: S12, adjusting the vertical load to obtain a plurality of vertical stresses detected by a plurality of the first detection members (10) under different vertical loads.

8. The vehicle body fatigue life testing method according to claim 1, characterized in that: In step S4, the time domain signal is a sinusoidal time domain signal.

9. A computer storage medium, characterized in that The computer storage medium is used to store a program, wherein when the program is executed, the device where the computer storage medium is located is controlled to execute the vehicle body fatigue life test method according to any one of claims 1 to 8.

10. An electronic device comprising a memory and a processor, characterized in that: The memory stores a computer program, and the processor is configured to execute the vehicle body fatigue life test method according to any one of claims 1 to 8 through the computer program.

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