Fatigue performance test device and method

Abstract

The invention belongs to the technical field of engineering structure performance testing, and discloses a fatigue performance testing device and method. The fatigue performance test device comprises a base, a fixing assembly, a first loading assembly and a second loading assembly. The direction and position of the first mounting rack on the surface of the base are adjustable to adjust the direction of a pressure dynamic load applied by the first loading unit, and the direction and position of the second mounting rack on the surface of the base are adjustable to adjust the direction of a tension dynamic load applied by the second loading unit. According to the fatigue performance test device provided by the invention, the working condition that a pressure dynamic load changes in the adjusting direction of the first mounting frame and the working condition that a tension dynamic load changes in the adjusting direction of the second mounting frame can be simulated, so that the simulated dynamic load working condition is closer to the dynamic load borne by a test piece in actual use; and the accuracy of the fatigue performance test result of the test piece is improved. The invention further provides a fatigue performance test method. The fatigue performance test device is used for carrying out fatigue performance test on a test piece.

Description

Technical Field

[0001] The present invention relates to the technical field of engineering structure performance testing, and in particular to a fatigue performance testing device and method. Background Art

[0002] In order to evaluate the performance of engineering structures and materials under alternating loads, predict their fatigue life, and ensure the safety and reliability of engineering structures, it is of great significance to conduct fatigue performance tests on engineering structures.

[0003] The related technology discloses a large-scale structural fatigue testing machine, which includes a base, a crossbeam assembly, a column, a lifting cylinder and an anti-lateral force assembly. A first fatigue actuator is provided at the bottom of the crossbeam assembly for applying a vertical load to the specimen. A second fatigue actuator is provided on the anti-lateral force assembly for applying a horizontal load to the specimen, which can simulate the dynamic load borne by the specimen from two directions respectively.

[0004] However, engineering structures are often subjected to complex dynamic loads during use, such as earthquakes, wind loads, mechanical equipment vibrations, and traffic loads. The above-mentioned testing machines cannot truly simulate the complex and multi-directional dynamic load conditions that engineering structures are subjected to. Therefore, the fatigue performance test results of engineering structures cannot accurately reflect their fatigue life during actual use. Summary of the Invention

[0005] The purpose of the present invention is to provide a fatigue performance testing device and method to solve the technical problem that fatigue testing machines in the prior art can only simulate dynamic loads in a fixed direction and cannot truly simulate the complex multi-directional dynamic load conditions borne by engineering structures.

[0006] To achieve this object, the present invention adopts the following technical solutions:

[0007] In one aspect, a fatigue performance testing device is provided, comprising:

[0008] base;

[0009] A fixing assembly, the fixing assembly being disposed on the base and being used to fix the specimen to the base;

[0010] a first loading assembly, the first loading assembly comprising a first mounting frame and a first loading unit, the first mounting frame being adjustable in direction and position on the surface of the base, the first loading unit being connected to the first mounting frame, and the first loading unit being configured to apply a compressive dynamic load to the specimen;

[0011] The second loading assembly includes a second mounting frame and a second loading unit, the second mounting frame is adjustable in direction and position on the base surface, the second loading unit is connected to the second mounting frame, and the second loading unit is used to apply a tensile dynamic load to the specimen.

[0012] Optionally, the base includes a base body, a first bearing part, a second bearing part and a locking assembly, the first bearing part and the second bearing part are coaxially rotatably arranged on the base body, the first mounting bracket is eccentrically connected to the first bearing part, the second mounting bracket is eccentrically connected to the second bearing part, and the locking assembly is used to lock and fix the first bearing part and the second bearing part.

[0013] Optionally, the locking assembly includes a first plug-in structure and a pin hole that are plug-fitted together, and a plurality of the pin holes are arranged on the first bearing part and the second bearing part at circumferential intervals, and each of the pin holes on the first bearing part is aligned with a pin hole on the second bearing part.

[0014] Optionally, the first loading assembly further includes a first carrying arm, the first loading unit is mounted on the first mounting frame via the first carrying arm, and the first carrying arm can be raised and lowered on the first mounting frame; and / or the first loading unit can be flipped on the first mounting frame.

[0015] Optionally, the first loading unit is flippably disposed on the first carrying arm, the first carrying arm extends in a horizontal direction, and the length of the first carrying arm is adjustable.

[0016] Optionally, the second loading unit includes a flexible connection member, a first driving member and a reversing assembly, the first driving member is connected to the test piece via the flexible connection member, and the reversing assembly abuts against the flexible connection member;

[0017] The reversing assembly can be lifted and lowered on the second mounting frame, and / or the reversing assembly extends in a horizontal direction and the length of the reversing assembly is adjustable.

[0018] Optionally, the second loading unit further includes a clamping member, and the flexible connecting member is fixedly connected to the test piece via the clamping member.

[0019] Optionally, the clamping member includes a clamping ring, an adjusting screw and an arc-shaped fixing plate, wherein a plurality of adjusting screws are arranged at circumferential intervals along the clamping ring, and the adjusting screws are threadedly connected to the clamping ring, the arc-shaped fixing plate is arranged one-to-one at one end of the adjusting screw located in the clamping ring, and the flexible connecting member is connected to the clamping ring.

[0020] Optionally, the fixing assembly includes a bolt and a nut, the base is provided with at least one slide groove extending along the first direction, the head of the bolt is slidably disposed in the slide groove, and the rod of the bolt can be inserted into the test piece, and the nut is sleeved on the bolt;

[0021] And / or, the fixing assembly includes clamping seats, at least two of which are symmetrically arranged on the base along a second direction and can move along the first direction to clamp or release the specimen, and the second direction is perpendicular to the first direction.

[0022] On the other hand, a fatigue performance test method is provided, wherein the fatigue performance test is performed on the specimen using the fatigue performance test apparatus. The fatigue performance test method comprises the following steps:

[0023] S1, fixing the specimen to the base using the fixing assembly;

[0024] S2. Install a strain gauge on the test piece, attach a strain gauge, and install a displacement sensor;

[0025] S3, adjusting the directions and positions of the first loading assembly and the second loading assembly relative to the specimen;

[0026] S4. Setting loading parameters of the first loading unit and the second loading unit according to test requirements and loading the specimen, obtaining stress, strain, and displacement data of the specimen, and observing the appearance of the specimen for cracks, paint peeling, and / or deformation;

[0027] S5. Repeat steps S3 and S4 to calculate the stress amplitude, strain amplitude, and displacement amplitude parameters of the specimen based on the collected stress, strain, and displacement data, and draw the change curves between the stress amplitude, strain amplitude, and displacement amplitude and the applied load, respectively, to analyze the change law of the fatigue performance of the specimen.

[0028] Beneficial effects of the present invention:

[0029] The present invention provides a fatigue performance testing device for fatigue performance testing of engineering structure specimens, comprising a base, a fixing assembly, a first loading assembly, and a second loading assembly. The base is used to support the engineering structure specimen, and the fixing assembly is arranged on the base to fix the specimen to the base. The direction and position of the first mounting bracket on the surface of the base are adjustable to adjust the direction of the compressive dynamic load applied to the specimen by the first loading unit, and the direction and position of the second mounting bracket on the surface of the base are adjustable to adjust the direction of the tensile dynamic load applied to the specimen by the second loading unit. Compared with the fatigue testing machine in the prior art that can only simulate dynamic loads in a fixed direction, the fatigue performance testing device provided by the present invention can simulate the working conditions of the compressive dynamic load changing in the adjustment direction of the first mounting bracket and the tensile dynamic load changing in the adjustment direction of the second mounting bracket, so that the simulated dynamic load working conditions are closer to the dynamic load borne by the specimen in actual use, further improving the accuracy of the fatigue performance test results of the specimen. The present invention also provides a fatigue performance testing method, using the above-mentioned fatigue performance testing device to perform fatigue performance testing on the specimen. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 1 is a schematic structural diagram of a fatigue performance testing device according to an embodiment of the present invention;

[0031] Figure 2 is a cross-sectional view of a fatigue performance testing device according to an embodiment of the present invention;

[0032] Figure 3 Schematic diagram of the structure and positional relationship of the first bearing portion, the second bearing portion, and the locking assembly according to an embodiment of the present invention;

[0033] Figure 4 is a schematic structural diagram of the first loading component according to an embodiment of the present invention;

[0034] Figure 5 is a schematic structural diagram of the second loading assembly according to an embodiment of the present invention;

[0035] Figure 6 1 is a schematic structural diagram of a reversing assembly according to an embodiment of the present invention;

[0036] Figure 7 1 is a schematic structural diagram of a clamping member according to an embodiment of the present invention;

[0037] Figure 8 is an exploded view of the base and the fixing assembly according to an embodiment of the present invention;

[0038] Figure 9 It is a structural schematic diagram of the exposed column base support according to an embodiment of the present invention when it is fixed to a fatigue performance testing device.

[0039] In the picture:

[0040] 1. Base; 11. Base body; 12. First bearing part; 13. Second bearing part; 14. Locking assembly; 141. First plug-in structure; 142. Pin hole; 15. Slide groove; 2. Fixing assembly; 21. Clamping seat; 3. First loading assembly; 31. First mounting bracket; 32. First loading unit; 33. First bearing arm; 4. Second loading assembly; 41. Second mounting bracket; 42. Second loading unit; 421. Flexible connector; 422. First driving member; 423. Reversing assembly; 4231. Guide wheel; 4232. Second bearing arm; 4233. Adjusting rod; 424. Clamping member; 4241. Clamping ring; 4242. Adjusting screw; 4243. Arc fixing plate. DETAILED DESCRIPTION

[0041] The following describes embodiments of the present invention in detail. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar components or components having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to explain the present invention, but are not to be construed as limiting the present invention.

[0042] In the description of the present invention, unless otherwise expressly specified or limited, the terms "connected," "connected," and "fixed" should be understood in a broad sense. For example, they may refer to fixed or detachable connections, mechanical or electrical connections, direct or indirect connections through an intermediate medium, and internal communication between two elements or interaction between two elements. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0043] In the description of the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first feature being in direct contact with the second feature, or may include the first feature being in contact with the second feature through another feature between them instead of being in direct contact. Moreover, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0044] The technical solution of the present invention will be further described below with reference to the accompanying drawings and through specific implementation methods.

[0045] like Figure 1As shown, the present invention provides a fatigue performance testing device for fatigue performance testing of engineering structure specimens, comprising a base 1, a fixing assembly 2, a first loading assembly 3 and a second loading assembly 4. The fixing assembly 2 is arranged on the base 1, and is used to fix the specimen to the base 1. The first loading assembly 3 includes a first mounting frame 31 and a first loading unit 32. The direction and position of the first mounting frame 31 on the surface of the base 1 are adjustable. The first loading unit 32 is connected to the first mounting frame 31. The first loading unit 32 is used to apply a compressive dynamic load to the specimen. The second loading assembly 4 includes a second mounting frame 41 and a second loading unit 42. The direction and position of the second mounting frame 41 on the surface of the base 1 are adjustable. The second loading unit 42 is connected to the second mounting frame 41. The second loading unit 42 is used to apply a tensile dynamic load to the specimen.

[0046] The first loading unit 32 can change the direction of the compressive dynamic load applied to the specimen as the direction and position of the first mounting frame 31 on the base 1 are adjusted. The second loading unit 42 can change the direction of the tensile dynamic load applied to the specimen as the direction and position of the second mounting frame 41 on the base 1 are adjusted. Compared with the fatigue testing machine in the prior art that can only simulate dynamic loads in a fixed direction, the fatigue performance testing device provided by the present invention can simulate the working conditions of the compressive dynamic load changing in the adjustment direction of the first mounting frame 31 and the tensile dynamic load changing in the adjustment direction of the second mounting frame 41, so that the simulated dynamic load working conditions are closer to the dynamic load that the specimen bears during actual use, expands the scope and accuracy of the fatigue test, and further improves the accuracy of the fatigue performance test results of engineering structure specimens.

[0047] Specifically, if Figure 1-Figure 3As shown, the base 1 includes a base body 11, a first bearing part 12, a second bearing part 13 and a locking assembly 14. The first bearing part 12 and the second bearing part 13 are coaxially rotatably arranged on the base body 11. The locking assembly 14 is arranged on the base body 11. The first mounting bracket 31 is eccentrically connected to the first bearing part 12, and the second mounting bracket 41 is eccentrically connected to the second bearing part 13. The locking assembly 14 is used to lock and fix the first bearing part 12 and the second bearing part 13. When the fatigue performance testing apparatus needs to adjust the direction of the compressive and tensile dynamic loads, the locking assembly 14 releases the lock on the first bearing portion 12 and the second bearing portion 13. The first mounting bracket 31 adjusts the direction and position of the first bearing portion 12 on the base 1 by rotating the first bearing portion 12. The first loading unit 32 rotates with the first mounting bracket 31 to adjust the direction, i.e., adjust the direction of the compressive dynamic load. The second mounting bracket 41 adjusts the direction and position of the second bearing portion 13 on the base 1 by rotating the second bearing portion 13. The second loading unit 42 rotates with the second mounting bracket 41 to adjust the direction, i.e., adjust the direction of the tensile dynamic load. After the direction adjustment of the compressive and tensile dynamic loads is completed, the locking assembly 14 locks and secures the first bearing portion 12 and the second bearing portion 13, thereby fixing the direction of the compressive and tensile dynamic loads and preventing errors in the test results due to positional deviations between the first loading assembly 3 and the second loading assembly 4.

[0048] Further, if Figure 2 and Figure 3 As shown, the locking assembly 14 includes a first plug-in structure 141 and a pin hole 142 that are pluggable. The first load-bearing portion 12 and the second load-bearing portion 13 each include an annular body and a plurality of pin holes 142 spaced circumferentially along the annular body. Each pin hole 142 on the first load-bearing portion 12 is aligned with a pin hole 142 on the second load-bearing portion 13. When the first load-bearing portion 12 and the second load-bearing portion 13 need to be locked and fixed, the first plug-in structure 141 can be pluggable and mated with the pin holes 142 on the first load-bearing portion 12 and the pin holes 142 on the second load-bearing portion 13. When the first load-bearing portion 12 and the second load-bearing portion 13 need to be unlocked, the first plug-in structure 141 can be separated from the pin holes 142 on the first load-bearing portion 12 and the pin holes 142 on the second load-bearing portion 13.

[0049] Alternatively, as Figure 2 and Figure 3As shown, the base 11 has a cavity within it. The first and second supporting portions 12, 13 are coaxially rotatably disposed within the cavity of the base 11 via a rotating shaft. A stopper is provided on the rotating shaft to prevent the first and second supporting portions 12, 13 from moving up and down. A locking assembly 14 is disposed within the cavity, with the second supporting portion 13 positioned above the first supporting portion 12 and the locking assembly 14 positioned below the first supporting portion 12. The upper end surface of the first supporting portion 12 is provided with a first connecting portion for connecting to the first mounting bracket 31, while the upper end surface of the second supporting portion 13 is provided with a second connecting portion for connecting to the second mounting bracket 41. The upper wall of the cavity of the base 11 is provided with an arcuate groove for the first and second connecting portions to pass through the cavity. The first connecting portion rotates with the first supporting portion 12, thereby changing the orientation and position of the first mounting bracket 31 on the surface of the base 1. The second connecting portion rotates with the second supporting portion 13, thereby changing the orientation and position of the second mounting bracket 41 on the surface of the base 1. The locking assembly 14 also includes a second drive member and a retaining ring. The second drive member is fixedly connected to the base 1, and the retaining ring is connected to the output end of the second drive member. A plurality of first plug-in structures 141 are circumferentially spaced apart on the retaining ring, and the first plug-in structures 141 are aligned with the pin holes 142 of the first and second load-bearing portions 12, 13. The second drive member can drive the retaining ring toward or away from the first and second load-bearing portions 12, 13, causing the first plug-in structures 141 to engage or disengage with the pin holes 142, thereby locking or releasing the first and second load-bearing portions 12, 13. By arranging a plurality of first plug-in structures 141 at intervals on the retaining ring, the locking stability of the locking assembly 14 on the first and second load-bearing portions 12, 13 is improved. Specifically, the first plug-in structure 141 is a pin disposed on the retaining ring and aligned with each pin hole 142. The pin holes 142 on the first and second load-bearing portions 12, 13 are aligned, so that the same pin is used to simultaneously lock the first and second load-bearing portions 12, 13. It is understood that the second driving member may be a pneumatic cylinder, a hydraulic cylinder, or an electric push rod, and details thereof will not be repeated here.

[0050] Alternatively, as Figure 1 and Figure 4 As shown, the first loading assembly 3 further includes a first carrying arm 33, through which the first loading unit 32 is mounted on the first mounting frame 31. The first carrying arm 33 is arbitrarily disposed on the first mounting frame 31. The first loading unit 32 can adjust its vertical height as the first carrying arm 33 is raised or lowered, so as to apply a compressive dynamic load to specimens of different heights or to different height positions of the same specimen.

[0051] Specifically, if Figure 4As shown, a first lifting seat is provided at one end of the first carrying arm 33, and the first lifting seat is guide-connected to the first mounting frame 31. The first mounting frame 31 is also provided with a third driving member for driving the first lifting seat to rise and fall in the vertical direction. Similarly, the third driving member can be a pneumatic cylinder, a hydraulic cylinder or an electric push rod, etc., which will not be repeated here.

[0052] Furthermore, the first loading unit 32 can be flipped and arranged on the first mounting frame 31, so that the first loading unit 32 can apply pressure dynamic loads in different directions in the vertical plane to the test piece.

[0053] In one embodiment, the first loading assembly 3 further includes a fourth driving member, which is disposed on the first mounting frame 31 and is configured to drive the first loading unit 32 to flip on the first mounting frame 31. The fourth driving member may be a pneumatic cylinder, a hydraulic cylinder, or an electric push rod, and details thereof will not be repeated here.

[0054] More specifically, the first loading unit 32 is disposed on a first carrying arm 33 , which extends horizontally and has an adjustable length, so that the first loading unit 32 can apply a pressure dynamic load to specimens with different circumferential profile sizes.

[0055] In one embodiment, Figure 4 As shown, the first carrying arm 33 further includes a fixed portion, a telescopic portion, and a fifth driving member. The fixed portion is connected to the first lifting seat, the telescopic portion is movably mounted on the fixed portion, the first loading unit 32 is mounted on the telescopic portion, and the fifth driving member is mounted on the first lifting seat and is configured to drive the telescopic portion to move horizontally on the fixed portion to adjust the length of the first carrying arm 33. Optionally, the fifth driving member is a drive motor, the output end of which is connected to the telescopic portion via a screw.

[0056] Furthermore, the first loading unit 32 includes a sixth drive member. Optionally, the sixth drive member is a hydraulic cylinder. When high-pressure hydraulic oil enters the hydraulic cylinder, it can apply a pressure dynamic load to the specimen. A hydraulic pump for supplying oil to the hydraulic cylinder is provided on one side of the base 1. The first loading unit 32 also includes a loading head. The sixth drive member outputs the pressure dynamic load and transmits it to the specimen through the loading head. The first loading unit 32 can also be an electric servo actuator or an electromagnetic actuator. Specifically, the loading head is threadedly connected to the sixth drive member, facilitating replacement of the loading head when fatigue performance testing is performed on specimens of different sizes.

[0057] like Figure 1 and Figure 5 As shown, the second loading unit 42 includes a flexible connection member 421 and a first driving member 422 . The first driving member 422 is connected to the specimen through the flexible connection member 421 to apply a tensile dynamic load to the specimen.

[0058] To adjust the direction of the tensile dynamic load applied to the specimen by the flexible connector 421 in the vertical plane, the second loading unit 42 also includes a reversing assembly 423. The reversing assembly 423 abuts the flexible connector 421, and the abutment position between the reversing assembly 423 and the flexible connector 421 is adjustable. A pressure sensor is also mounted on the flexible connector 421 for real-time monitoring of the tensile force of the flexible connector 421.

[0059] For example, Figure 5 and Figure 6 As shown, the reversing assembly 423 includes a guide wheel 4231 and a second supporting arm 4232. The guide wheel 4231 is rotatably arranged at one end of the second supporting arm 4232 via a rotating shaft. The guide wheel 4231 can flexibly adjust the force direction of the flexible connector 421 and reduce the wear of the flexible connector 421.

[0060] In one embodiment, the reversing assembly 423 is arbitrarily mounted on the second mounting frame 41. Specifically, a second lifting seat is provided at the other end of the second supporting arm 4232, which is in a guide connection with the second mounting frame 41. A seventh driving member is also provided on the second mounting frame 41 to vertically drive the second lifting seat. Optionally, the seventh driving member may be a pneumatic cylinder, a hydraulic cylinder, or an electric push rod. The reversing assembly 423 adjusts its vertical height via the seventh driving member, thereby adjusting its position relative to the flexible connector 421 and thereby adjusting the direction of force applied to the flexible connector 421.

[0061] In another embodiment, the reversing assembly 423 extends in the horizontal direction and has an adjustable length. Figure 6As shown, the second supporting arm 4232 includes a sleeve and an extension column. One end of the sleeve is fixedly connected to the second lifting seat, the extension column is inserted into the sleeve, and the guide wheel 4231 is rotatably connected to the end of the extension column. The length of the extension column inserted into the sleeve is adjustable, thereby adjusting the horizontal length of the second supporting arm 4232. Optionally, the reversing assembly 423 also includes an adjustment rod 4233, which includes two threaded columns and an internally threaded sleeve. The extension column is provided with a mounting portion at one end near the guide wheel 4231. The two threaded columns are rotatably connected to the mounting portion and the second lifting seat, respectively. The two threaded columns are connected by the internally threaded sleeve. When the direction of the tensile dynamic load applied to the specimen needs to be changed, the internally threaded sleeve is rotated to extend the threaded column out of the internally threaded sleeve, pushing the extension column to move within the sleeve, causing the guide wheel 4231 to move horizontally. The guide wheel 4231 abuts against the flexible connector 421, thereby changing the direction of the tensile dynamic load. The horizontal length of the second supporting arm 4232 is adjusted by the adjusting rod 4233. Compared with adjusting the length of the second supporting arm 4232 by means of a threaded connection between the extension column and the sleeve, this can effectively prevent the guide wheel 4231 from rotating with the extension column, thereby causing the flexible connector 421 to be entangled on the guide wheel 4231. Compared with adjusting the length of the second supporting arm 4232 by setting a limit pin on the sleeve and the extension column, the adjusting rod 4233 can more accurately control the length adjustment range of the second supporting arm 4232.

[0062] It can be understood that the sleeve, extension column and adjustment rod 4233 used to adjust the horizontal length of the reversing component 423 are all connected to the second lifting seat, and the reversing component 423 can also adjust its contact position with the flexible connector 421 by adjusting the length and height at the same time.

[0063] Optionally, the second loading unit 42 also includes an I-shaped wheel, which can enable the flexible connector 421 to be quickly retracted and extended and reduce the wear of the second mounting frame 41 on the flexible connector 421. The I-shaped wheel and the first driving member 422 are arranged on the top of the second mounting frame 41. The first driving member 422 can be a driving motor or a pneumatic motor. One end of the flexible connector 421 is wound around the I-shaped wheel, and the other end is connected to the test piece. Exemplarily, the flexible connector 421 is a steel wire rope or a synthetic fiber rope.

[0064] Alternatively, as Figure 5 and Figure 7As shown, the second loading unit 42 also includes a clamping member 424, and the flexible connecting member 421 is fixedly connected to the specimen through the clamping member 424, further improving the connection stability between the second loading assembly 4 and the specimen. Specifically, the clamping member 424 includes a clamping ring 4241, an adjusting screw 4242, and an arc-shaped fixing plate 4243. A plurality of adjusting screws 4242 are arranged at intervals along the circumference of the clamping ring 4241. The adjusting screw 4242 is threadedly connected to the clamping ring 4241, and the flexible connecting member 421 is connected to the clamping ring 4241. The arc-shaped fixing plate 4243 is arranged in a one-to-one correspondence with one end of the adjusting screw 4242 located within the clamping ring 4241. By rotating the adjusting screw 4242, the arc-shaped fixing plate 4243 is tightly fitted to the specimen. The clamping member 424 is also provided with a connecting ring for connecting to the flexible connecting member 421.

[0065] Alternatively, as Figure 1 and Figure 8 As shown, the fixing assembly 2 includes a bolt and a nut, and the base 1 is provided with at least one Figure 8 A slot 15 extends (in the X-direction) in the center of the test specimen. The head of the bolt slides within the slot 15, and the shank of the bolt can be inserted into the test specimen. A nut is sleeved over the shank of the bolt to secure the test specimen. A notch is provided at one end of the slot 15 for the bolt head to enter and exit. When installing the test specimen, the operator selects the appropriate bolt based on the size of the mounting hole on the test specimen through which the bolt passes. In one embodiment, two slots 15 are provided on the upper surface of the base 1, each of which slides two bolts.

[0066] The fixing assembly 2 further includes a clamping seat 21 and an eighth driving member, at least two clamping seats 21 along the second direction ( Figure 8 The clamping mechanism is symmetrically arranged on the base 1 along the middle Y direction and can move along the first direction to clamp or release the specimen, and the second direction is perpendicular to the first direction.

[0067] In one embodiment, the upper surface of the base 1 is symmetrically provided with two grooves along the second direction. A clamping seat 21 is slidably connected to each groove. The clamping seat 21 at least partially protrudes from the upper surface of the base 1. The clamping seat 21 is driven to move by an eighth driving member. Opposing surfaces of the two clamping seats 21 are configured as clamping surfaces that are inclined from a direction away from the specimen toward a direction toward the specimen. When the two clamping seats 21 clamp the specimen, the clamping surfaces apply an oblique upward thrust to the specimen, further enhancing the connection strength between the specimen and the base 1 and improving the stability of the specimen during fatigue performance testing. The eighth driving member may be a pneumatic cylinder, a hydraulic cylinder, or an electric push rod, etc., and will not be described in detail here.

[0068] Furthermore, a buffer pad is provided on the upper surface of the base 1, and the buffer pad is provided between the base 1 and the test piece. The buffer pad can play a buffering role between the test piece and the base 1, thereby reducing the interference of vibration transmission to the surrounding environment and measuring instruments during the test.

[0069] In one embodiment, Figure 9 As shown, the engineering structure specimen is an exposed column base support. The exposed column base support includes a column base plate and a steel column arranged on the column base plate. The column base plate is fixed to the base 1 by four bolts, and two clamping seats 21 are respectively arranged on opposite sides of the column base plate. When the two clamping seats 21 clamp the column base plate, the clamping surface applies an oblique upward thrust to the column base plate, further improving the connection strength between the column base plate and the base 1. Specifically, the lower part of the loading head of the first loading unit 32 is provided with a circular groove corresponding to the steel column. The circular groove can abut the steel column from above, and the circular groove improves the stability of the abutment between the loading head and the steel column. The groove wall of the circular groove is also provided with an arc groove. When the first loading unit 32 abuts the steel column in the horizontal direction, the arc groove can increase the contact area between the loading head and the steel column, thereby improving the stability of the first loading unit 32 when applying a compressive dynamic load to the exposed column base support. The flexible connector 421 is sleeved on and fastened to the steel column of the exposed column base support. The flexible connector 421 is fixedly connected to the exposed column base support through the clamping member 424 and applies a tensile dynamic load to the exposed column base support.

[0070] An embodiment of the present invention further provides a fatigue performance test method, which uses the above fatigue performance test device to perform a fatigue performance test on a specimen, comprising the following steps:

[0071] S1. Use the fixing assembly 2 to fix the test piece to the base 1 according to the actual engineering installation method.

[0072] S2. Install stress gauges, affix strain gauges, and install displacement sensors on the specimen. Specifically, according to fatigue performance test standards, install stress gauges and affix strain gauges at key locations such as welds, hole edges, and cross-sectional changes. These are used to measure changes in stress and strain during compressive and tensile dynamic loads. Displacement sensors are installed at specimen connection nodes or locations where significant deformation may occur to monitor displacement changes during loading.

[0073] S3. Adjust the orientation and position of the first loading assembly 3 and the second loading assembly 4 on the surface of the base 1. Specifically, adjust the orientation and position of the first loading assembly 3 and the second loading assembly 4 relative to the specimen on the horizontal plane, and make the first loading unit 32 abut against the specimen, and the second loading unit 42 connect to the specimen.

[0074] S4. Set the loading parameters of the first loading unit 32 and the second loading unit 42 according to the test requirements and load the specimen. Obtain stress, strain, and displacement data for the specimen, while observing the specimen's appearance for cracks, paint peeling, and deformation. Specifically, set the loading parameters of the first loading unit 32 and the second loading unit 42 according to the fatigue performance test requirements, including the magnitude, frequency, and waveform of the pressure and tension. Preload the specimen. The preload force is generally 10%-20% of the set loading parameters. If any abnormality is found, stop loading immediately and investigate the cause. Adjust the specimen and then re-preload. If there are no abnormalities during preloading, formal loading can be performed on the specimen. Cyclic loads are applied to the specimen according to the set magnitude, frequency, and waveform to obtain stress, strain, and displacement data. Simultaneously, data for the dynamic pressure and tension loads are collected. The data collection interval can be set to 0.1 seconds and stored in a computer. During the loading process, observe the specimen's appearance for cracks, paint peeling, and deformation.

[0075] S5. Repeat steps S3 and S4 to calculate the stress amplitude, strain amplitude, and displacement amplitude parameters of the specimen based on the collected stress, strain, and displacement data, and plot the change curves of the stress amplitude, strain amplitude, and displacement amplitude versus the applied load, and analyze the change pattern of the fatigue performance of the specimen. Specifically, the test data collected is analyzed regularly, and the stress amplitude, strain amplitude, displacement amplitude, and other parameters of the specimen are calculated based on the collected stress, strain, and displacement data. The change curves of the stress amplitude, strain amplitude, displacement amplitude, and other parameters versus the applied load are plotted, and the change pattern of the above parameters with the number of loading cycles is observed. The change pattern of the fatigue performance of the specimen is analyzed to determine whether the specimen is in a normal fatigue working state.

[0076] Obviously, the above embodiments of the present invention are merely examples for the purpose of clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Those skilled in the art will appreciate that other variations or modifications can be made based on the above description. It is not necessary and impossible to enumerate all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the claims of the present invention.

Claims

1. Fatigue performance testing device, characterized in that, The fatigue performance testing device comprises: Base (1); A fixing assembly (2), the fixing assembly (2) being arranged on the base (1), and the fixing assembly (2) being used to fix the test piece on the base (1); a first loading assembly (3), the first loading assembly (3) comprising a first mounting frame (31) and a first loading unit (32), the first mounting frame (31) being adjustable in direction and position on the surface of the base (1), the first loading unit (32) being connected to the first mounting frame (31), and the first loading unit (32) being used to apply a pressure dynamic load to the specimen; A second loading assembly (4), the second loading assembly (4) comprising a second mounting frame (41) and a second loading unit (42), the second mounting frame (41) being adjustable in direction and position on the surface of the base (1), the second loading unit (42) being connected to the second mounting frame (41), and the second loading unit (42) being used to apply a tensile dynamic load to the specimen.

2. The fatigue performance testing device according to claim 1, characterized in that: The base (1) comprises a base body (11), a first bearing part (12), a second bearing part (13) and a locking assembly (14); the first bearing part (12) and the second bearing part (13) are coaxially rotatably arranged on the base body (11); the first mounting frame (31) is eccentrically connected to the first bearing part (12); the second mounting frame (41) is eccentrically connected to the second bearing part (13); and the locking assembly (14) is used to lock and fix the first bearing part (12) and the second bearing part (13).

3. The fatigue performance testing device according to claim 2, characterized in that: The locking assembly (14) comprises a first plug-in structure (141) and a pin hole (142) for plug-in engagement, a plurality of the pin holes (142) are arranged on the first bearing portion (12) and the second bearing portion (13) at intervals along the circumferential direction, and each of the pin holes (142) on the first bearing portion (12) is aligned with a pin hole (142) on the second bearing portion (13).

4. The fatigue performance testing device according to any one of claims 1 to 3, characterized in that: The first loading assembly (3) further comprises a first carrying arm (33), the first loading unit (32) being mounted on the first mounting frame (31) via the first carrying arm (33), the first carrying arm (33) being movably mounted on the first mounting frame (31); and / or the first loading unit (32) being reversibly mounted on the first mounting frame (31).

5. The fatigue performance testing device according to claim 4, characterized in that: The first loading unit (32) is flippably arranged on the first carrying arm (33); the first carrying arm (33) extends in a horizontal direction and the length of the first carrying arm (33) is adjustable.

6. The fatigue performance testing device according to any one of claims 1 to 3, characterized in that: The second loading unit (42) comprises a flexible connection member (421), a first driving member (422) and a reversing assembly (423), wherein the first driving member (422) is connected to the test piece via the flexible connection member (421), and the reversing assembly (423) abuts against the flexible connection member (421); The reversing assembly (423) is movably mounted on the second mounting frame (41), and / or the reversing assembly (423) extends in a horizontal direction and the length of the reversing assembly (423) is adjustable.

7. The fatigue performance testing device according to claim 6, characterized in that: The second loading unit (42) further includes a clamping member (424), and the flexible connecting member (421) is fixedly connected to the test piece via the clamping member (424).

8. The fatigue performance testing device according to claim 7, characterized in that: The clamping member (424) includes a clamping ring (4241), an adjusting screw (4242) and an arc-shaped fixing plate (4243). A plurality of adjusting screws (4242) are arranged at intervals along the circumference of the clamping ring (4241), and the adjusting screw (4242) is threadedly connected to the clamping ring (4241). The arc-shaped fixing plate (4243) is arranged one-to-one at one end of the adjusting screw (4242) located in the clamping ring (4241), and the flexible connecting member (421) is connected to the clamping ring (4241).

9. The fatigue performance testing device according to any one of claims 1 to 3, characterized in that: The fixing assembly (2) includes a bolt and a nut. The base (1) is provided with at least one slide groove (15) extending in a first direction. The head of the bolt is slidably arranged in the slide groove (15), and the rod of the bolt can be inserted into the test piece. The nut is sleeved on the bolt. And / or, the fixing assembly (2) includes a clamping seat (21), at least two of the clamping seats (21) are symmetrically arranged on the base (1) along a second direction and can be moved along the first direction to clamp or release the specimen, and the second direction is perpendicular to the first direction.

10. Fatigue performance test method, characterized in that: A fatigue performance test is performed on the specimen using the fatigue performance test apparatus according to any one of claims 1 to 9, wherein the fatigue performance test method comprises the following steps: S1, using the fixing assembly (2) to fix the test piece to the base (1); S2. Install a strain gauge on the test piece, attach a strain gauge, and install a displacement sensor; S3, adjusting the directions and positions of the first loading assembly (3) and the second loading assembly (4) relative to the specimen; S4. Setting the loading parameters of the first loading unit (32) and the second loading unit (42) according to test requirements and loading the specimen, obtaining stress, strain and displacement data of the specimen, and observing the appearance of the specimen to see whether cracks, paint peeling and / or deformation occur; S5. Repeat steps S3 and S4 to calculate the stress amplitude, strain amplitude, and displacement amplitude parameters of the specimen based on the collected stress, strain, and displacement data, and draw the change curves between the stress amplitude, strain amplitude, and displacement amplitude and the applied load, respectively, to analyze the change law of the fatigue performance of the specimen.

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