Strength test apparatus and method

Abstract

The application discloses a strength detection test device and method, and belongs to the technical field of strength detection of railway vehicles, and comprises a T-shaped riveting joint, the bottom of the T-shaped riveting joint is fixed on a mounting platform, the top of the T-shaped riveting joint is connected with a loading mechanism, a strain gauge is arranged on the T-shaped riveting joint, and the strain gauge is connected with a strain collecting device through a connecting wire; the T-shaped riveting joint comprises first and second vertical plates which are arranged in close contact, and the bottom of each of the first and second vertical plates is fixedly connected with a connecting plate. The device can test the riveting strength of the T-shaped riveting joint and verify the reliability of the T-shaped riveting joint.

Description

Technical Field

[0001] This invention belongs to the field of strength testing technology for rail vehicle equipment, and specifically relates to a strength testing device and method. Background Technology

[0002] The statements herein provide only background information in relation to this invention and do not necessarily constitute prior art.

[0003] Currently, railway transportation equipment has also begun research on low-carbon technologies, and riveting connection technology, as a low-carbon connection technology, will be increasingly used in railway transportation equipment.

[0004] The underframe structure of rail transit vehicles generally consists of a center beam, crossbeams, sleeper beams, and side beams. The center beam is connected to the crossbeam, the crossbeam to the side beam, and the center beam to the end beam, with these connections being perpendicular or nearly perpendicular. T-shaped riveted joints can simulate this connection method and are used in rail transit vehicle equipment. T-shaped riveted joints use multiple sets of rivets, resulting in a relatively complex spatial structure and complex stresses under bending moments and tensile loads. The riveted structure relies on clamping force to ensure overall rigidity and on the friction between the plates to resist external loads. The material, surface finish, and rivet arrangement of the specimen all affect the performance of the T-shaped riveted joint. The stress on the rivets is a complex nonlinear process, and the stress distribution in the plate structure around the rivet head is extremely complex. Stress testing of this area is necessary to ensure the joint meets design requirements. Therefore, conducting strength tests on T-shaped riveted joints to verify the joint design is crucial for ensuring the performance of rail transit equipment products. Summary of the Invention

[0005] In view of the shortcomings of the existing technology, the purpose of this invention is to provide a strength testing device and method. This device can test the riveting strength of T-type riveting joints, verify the reliability of T-type riveting joints, and meet the needs of riveting structure design of rail transit vehicle equipment.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solution:

[0007] In a first aspect, the present invention provides a strength testing device, including a T-shaped riveting joint, the bottom of which is fixed to an installation platform, the top of which is connected to a loading mechanism, and strain gauges are provided on the T-shaped riveting joint, which are connected to a strain acquisition device via connecting lines; the T-shaped riveting joint includes a first vertical plate and a second vertical plate that are attached to each other, and the bottoms of the first vertical plate and the second vertical plate are fixedly connected to a connecting plate.

[0008] As a further technical solution, the first upright plate and the second upright plate are fixedly connected, and the tops of both the first upright plate and the second upright plate are connected to the loading mechanism.

[0009] As a further technical solution, the first upright plate is an L-shaped plate structure, which includes a first web plate and a first bottom plate; the first web plate and the first bottom plate are vertically connected, and the connection between the first web plate and the first bottom plate is provided with an arc.

[0010] As a further technical solution, the second upright plate is an L-shaped plate structure, which includes a second web plate and a second bottom plate; the second web plate and the second bottom plate are vertically connected, and the connection between the second web plate and the second bottom plate is provided with an arc.

[0011] As a further technical solution, the first web plate is vertically arranged, the first bottom plate is horizontally arranged, the second web plate is vertically arranged, and the second bottom plate is horizontally arranged; the first web plate and the second web plate are attached to each other, and the first web plate and the second web plate are fixedly connected by multiple vertical plate rivets, and the first vertical plate and the second vertical plate are connected to form a T-shaped structure.

[0012] As a further technical solution, both the first base plate and the second base plate are attached to the connecting plate, and both the first base plate and the second base plate are fixedly connected to the connecting plate by multiple base plate rivets.

[0013] As a further technical solution, the upper part of the first web and the second web is connected to the loading mechanism.

[0014] As a further technical solution, the connecting plate is a rectangular plate structure, and the ends of the connecting plate are fixedly connected to the installation platform.

[0015] As a further technical solution, the top of the loading mechanism is fixed to the loading mechanism mounting base, and the strain acquisition device is connected to the computer.

[0016] Secondly, the present invention also provides a test method for the strength testing device as described above, comprising the following steps:

[0017] Based on the connection between the middle beam and cross beam, the cross beam and the side beam, and the middle beam and the end beam of the rail vehicle, determine the material, plate thickness, size, and surface condition of the T-type riveting joint, and complete the fabrication of the T-type riveting joint.

[0018] Determine the strain gauge bonding layout based on the test conditions, complete the bonding of T-shaped riveted joint strain gauges, debug the test equipment, complete the wiring of the strain acquisition equipment, and check the resistance of the strain gauges;

[0019] Preliminary experiments were conducted, the T-type riveted joint was preloaded, stress data under the corresponding load was collected, and the data was analyzed to ensure the accuracy of the tooling and the test process.

[0020] Conduct formal tests and complete strain gauge data acquisition;

[0021] Analyze and process stress data, including data rationality analysis and compliance analysis.

[0022] The beneficial effects of the present invention are as follows:

[0023] The strength testing device of the present invention uses a T-shaped riveting joint to simulate the connection of various beams such as the middle beam and cross beam, the cross beam and side beam, and the middle beam and end beam of a rail transit vehicle. It has a simple structure, is easy to install, facilitates testing, reduces costs, improves the accuracy of T-shaped riveting structure design, and greatly improves the safety of rail transit riveting structures.

[0024] The strength testing device of the present invention allows the T-shaped riveting joint to be made of different materials to simulate different surface conditions and coating requirements of different plates, and is suitable for different connection methods.

[0025] The strength testing device of the present invention uses a T-shaped riveted joint that is supported by friction, and two vertical plates are set to facilitate the displacement and sliding of the connecting plates; it can simulate different materials and different processing (friction coefficient) conditions, taking into account a variety of factors.

[0026] The strength testing method of the present invention can perform strength tests on T-type riveted joints to verify the rationality of the connection method, shorten the product development cycle, and improve product reliability.

[0027] The strength testing method of the present invention can collect the stress of the plate around the rivet head, statistically analyze the stress distribution around the rivet head, and compare it with the calculated stress around the rivet head in the design to obtain a safety factor, thereby further ensuring the safety of the riveted joint. Attached Figure Description

[0028] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0029] Figure 1 This is a schematic diagram of the strength testing device of the present invention;

[0030] Figure 2 This is a structural diagram of the T-type riveting joint of the present invention;

[0031] Figure 3 This is a structural diagram of the first vertical plate of the present invention;

[0032] Figure 4 This is a structural diagram of the second vertical plate of the present invention;

[0033] Figure 5 This is a structural diagram of the connecting plate of the present invention;

[0034] Figure 6 This is a flowchart of the strength testing method of the present invention;

[0035] Figure 7 This is a diagram showing the strain gauge bonding arrangement of the present invention;

[0036] In the diagram: the spacing or dimensions between parts have been exaggerated to show their positions; the diagram is for illustrative purposes only.

[0037] Among them, 1 is the loading mechanism mounting base, 2 is the loading mechanism, 3 is the T-type riveting joint, 4 is the mounting platform, 5 is the connecting line, 6 is the strain acquisition equipment, 7 is the network cable, 8 is the computer, 9 is the first upright plate, 10 is the second upright plate, 11 is the upright plate rivet, 12 is the bottom plate rivet, 13 is the connecting plate, 14 is the first web plate, 15 is the first bottom plate, 16 is the second web plate, and 17 is the second bottom plate. Detailed Implementation

[0038] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0039] Example 1:

[0040] In a typical embodiment of the present invention, such as Figure 1 As shown, a strength testing device is proposed, including a loading mechanism mounting base 1, a loading mechanism 2, a T-shaped riveting joint 3, a mounting platform 4, a connecting line 5, a strain acquisition device 6, a network cable 7, and a computer 8.

[0041] The bottom of the T-shaped riveting joint 3 is fixed to the mounting platform 4, and the top of the T-shaped riveting joint 3 is connected to the loading mechanism 2 (the loading mechanism is a linear actuator, including but not limited to hydraulic cylinders, pneumatic cylinders, or electric actuators, which outputs force or displacement through the telescopic movement of the loading mechanism to achieve the purpose of loading). The top of the loading mechanism 2 is fixed to the loading mechanism mounting base 1. Strain gauges are installed on the T-shaped riveting joint 3, and the strain gauges are connected to the strain acquisition device 6 via connecting wire 5. The strain acquisition device 6 is connected to the computer 8 via network cable 7. The network cable 7 can be selected according to the strain acquisition device 6 and the computer 8, and can be optional.

[0042] The T-shaped riveting joint 3 includes a first upright plate 9, a second upright plate 10, an upright plate rivet 11, a bottom plate rivet 12, and a connecting plate 13. The first upright plate 9 and the second upright plate 10 are attached to each other and fixedly connected. The bottom of the first upright plate 9 and the second upright plate 10 are fixedly connected to the connecting plate 13, and the top of the first upright plate 9 and the second upright plate 10 are connected to the loading mechanism 2.

[0043] Specifically, the first upright plate 9 is an L-shaped plate structure, which includes a first web plate 14 and a first bottom plate 15; the first web plate 14 and the first bottom plate 15 are vertically connected, and the connection between the first web plate and the first bottom plate is provided with an arc.

[0044] The first web plate 14 is vertically arranged, and the first base plate 15 is horizontally arranged. Several round holes are opened on the first web plate 14 for connection with the second vertical plate 10 using vertical plate rivets 11. Several round holes are provided on the upper part of the first web plate 14 for connection with the loading mechanism 2 for loading. Several round holes are opened on the first base plate 15 for connection with the connecting plate 13 using base plate rivets 12.

[0045] Specifically, the second upright plate 10 is an L-shaped plate structure, which includes a second web plate 16 and a second bottom plate 17; the second web plate 16 and the second bottom plate 17 are vertically connected, and the connection between the second web plate and the second bottom plate is provided with an arc.

[0046] The second web plate 16 is vertically arranged, and the second base plate 17 is horizontally arranged. Several round holes are opened on the second web plate 16 for connection with the first upright plate 9 using upright plate rivets 11. Several round holes are provided on the upper part of the second web plate 16 for connection with the loading mechanism 2 for loading. Several round holes are opened on the second base plate 17 for connection with the connecting plate 13 using base plate rivets 12.

[0047] In the specific connection, the first web plate 14 of the first upright plate 9 and the second web plate 16 of the second upright plate 10 are attached to each other, and the positions of the round holes of the first web plate 14 and the second web plate 16 are corresponding. They are fixedly connected by multiple upright plate rivets 11. After the first upright plate 9 and the second upright plate 10 are connected, a T-shaped structure is formed. The first bottom plate 15 of the first upright plate 9 and the second bottom plate 17 of the second upright plate 10 are both attached to the connecting plate 13 and fixedly connected by multiple bottom plate rivets 12.

[0048] The round holes on the upper part of the first web plate 14 and the second web plate 16 are connected to the loading mechanism, and the two ends of the connecting plate 13 are fixedly connected to the mounting platform 4.

[0049] The connecting plate 13 is a rectangular plate structure that fits together with the first base plate 15 of the first upright plate 9 and the second base plate 17 of the second upright plate 10. Several round holes are provided in the middle of the connecting plate 13, the positions of which correspond to the positions of the round holes in the first base plate 15 and the second base plate 17, and the plates are connected by base plate rivets 12. Several round holes are provided at the ends of the connecting plate 13 for fixing to the mounting platform 4.

[0050] In this embodiment, the upright plate rivet 11 and the bottom plate rivet 12 are pull rivet structures, and the pull rivets can be of various specifications and sizes.

[0051] In this embodiment, the first upright plate 9, the second upright plate 10 and the connecting plate 13 are of various specifications and sizes, and different metal materials can be selected according to requirements. The surfaces of each plate are processed by the same or different methods, and have the same or different roughness levels. The surfaces of each plate are coated with different coatings.

[0052] Example 2:

[0053] In another typical embodiment of the present invention, such as Figure 6 As shown, a test method for the strength testing device described above is proposed, which includes the following steps:

[0054] (a) Based on the connection of each beam in the rail vehicle, such as the middle beam and cross beam, the cross beam and the side beam, the middle beam and the end beam, determine the material, plate thickness, and size of the T-type riveting joint (based on the stress of the rail transit vehicle, select the location of the T-type joint where the stress is high and design the T-type joint), as well as the surface condition of the T-type riveting joint, such as roughness and coating requirements, and complete the design and fabrication of the T-type riveting joint.

[0055] (b) Using the finite element method, the strain gauge placement diagram for the T-type riveted joint was determined based on the test conditions, as follows: Figure 7 (The strain gauge placement is based on the design of the riveted joint, covering the maximum stress of the riveted joint. Multiple strain gauges are placed on the specimen around the rivet head with the highest stress, the location of structural cross-section changes, and the location of design concern.) Complete the specimen test outline.

[0056] (c) According to the strain gauge bonding layout diagram, complete the bonding of the T-shaped riveted joint strain gauges, debug the test equipment, ensure the correctness of the load application position and loading constraint position, complete the wiring of the strain acquisition equipment, and check the resistance of the strain gauges, etc.

[0057] (d) Conduct a preliminary test, preload the T-type riveted joint with the load specified in the design conditions or a slightly smaller load, collect stress data under the corresponding load, analyze the data, and ensure the accuracy of the tooling and the test process.

[0058] (e) Conduct formal tests and collect strain gauge data using the loads specified in the design conditions;

[0059] (f) Analyze and process stress data (data analysis includes data rationality analysis and compliance analysis. Rationality analysis includes the symmetry of symmetrical points, loading load data, etc. Compliance is that the stress at each strain gauge bonding position is less than the allowable stress at that location. Analyze the stress around the rivet head and compare it with the stress around the rivet calculated in the engineering, summarize the magnitude of the stress around the rivet head, and design and develop the riveting structure based on the experimental data in subsequent designs), and complete the test report according to the standards.

[0060] In step (d), if the test data is unreasonable after the pre-loading test, the reasons need to be analyzed, the rationality of the test fixture needs to be evaluated, the test loading process needs to be analyzed, the reasons need to be sought and rectified.

[0061] In step (e), a formal test is conducted, which must be performed at least three times. The first test is a residual stress removal test. If the strain gauge does not return to zero properly, the number of tests needs to be increased. After the stress at the measuring point returns to zero normally, the data from the last test or the average of the last two test data is collected as the test stress at the measuring point.

[0062] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A strength testing method, characterized in that, The device includes a T-shaped riveting joint, with its bottom fixed to the installation platform and its top connected to the loading mechanism. A strain gauge is installed on the T-shaped riveting joint, and the strain gauge is connected to a strain acquisition device via a connecting wire. The T-shaped riveting joint includes a first vertical plate and a second vertical plate that are attached to each other, and the bottoms of both the first and second vertical plates are fixedly connected to a connecting plate. The first upright plate is an L-shaped plate structure, which includes a first web plate and a first bottom plate; the second upright plate is an L-shaped plate structure, which includes a second web plate and a second bottom plate; the first bottom plate and the second bottom plate are both attached to the connecting plate, and the first bottom plate and the second bottom plate are both fixedly connected to the connecting plate by multiple bottom plate rivets; The test method includes the following steps: Based on the connection between the middle beam and cross beam, the cross beam and the side beam, and the middle beam and the end beam of the rail vehicle, determine the material, plate thickness, size, and surface condition of the T-type riveting joint, and complete the fabrication of the T-type riveting joint. Determine the strain gauge bonding layout based on the test conditions, complete the bonding of T-shaped riveted joint strain gauges, debug the test equipment, complete the wiring of the strain acquisition equipment, and check the resistance of the strain gauges; Preliminary experiments were conducted, and the T-type riveted joint was preloaded. Stress data under the corresponding load was collected, and the data was analyzed to ensure the accuracy of the tooling and the test process. Conduct formal tests and complete strain gauge data acquisition; Analyze and process stress data, including data rationality analysis and compliance analysis.

2. The strength testing method as described in claim 1, characterized in that, The first and second upright plates are fixedly connected, and the tops of both the first and second upright plates are connected to the loading mechanism.

3. The strength testing method as described in claim 1, characterized in that, The first web plate and the first bottom plate are vertically connected, and the connection between the first web plate and the first bottom plate is provided with an arc.

4. The strength testing method as described in claim 1, characterized in that, The second web plate and the second bottom plate are vertically connected, and the connection between the second web plate and the second bottom plate is provided with an arc.

5. The strength testing method as described in claim 1, characterized in that, The first web plate is set vertically, the first bottom plate is set horizontally, the second web plate is set vertically, and the second bottom plate is set horizontally; the first web plate and the second web plate are attached to each other and are fixedly connected by multiple vertical plate rivets, and the first vertical plate and the second vertical plate are connected to form a T-shaped structure.

6. The strength testing method as described in claim 1, characterized in that, The upper part of the first web and the second web is connected to the loading mechanism.

7. The strength testing method as described in claim 1, characterized in that, The connecting plate is a rectangular plate structure, and its ends are fixedly connected to the installation platform.

8. The strength testing method as described in claim 1, characterized in that, The top of the loading mechanism is fixed to the loading mechanism mounting base, and the strain acquisition device is connected to the computer.

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