Bending and torsion fatigue test device

Abstract

The present application relates to the technical field of bending and torsion fatigue testing, and provides a bending and torsion fatigue test device, for use in solving the technical problem of the complex structure of a rotating bending fatigue test device. The bending and torsion fatigue test device comprises: a base, two loading assemblies, and a test piece. The base is provided with two arc-shaped tracks, and the two arc-shaped tracks are symmetrically arranged on the base in a first direction. The two loading assemblies are respectively movably connected to the two arc-shaped tracks, wherein one loading assembly is connected to one corresponding arc-shaped track. Each loading assembly comprises two loading members, and the two loading members move towards or away from each other along the corresponding arc-shaped tracks. The test piece is located between the two loading assemblies, and each loading member is in direct contact with the test piece. The present application is used for detecting and evaluating the bending and torsion fatigue life of the test piece, and the test device has a simple structure.

Description

Bending and torsional fatigue testing device

[0001] This application claims priority to Chinese Patent Application No. 202411533005.0, filed on October 30, 2024, entitled "Bending and Torsional Fatigue Testing Device", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of bending and torsional fatigue testing technology, and in particular to a bending and torsional fatigue testing device. Background Technology

[0003] In the exploration and development of oil and gas resources, downhole tools often need to provide torque to downhole rock-breaking tools (drill bits) by rotation. At the same time, due to the constraints of the wellbore, such as the rate of change of the total angle of the wellbore in vertical wells and the build-up point in directional or horizontal wells, downhole tools will inevitably undergo elastic bending deformation.

[0004] For example, drill pipes in oil wells typically play a crucial role in bearing and transmitting torsional forces during their service life, and their lifespan directly affects the safety of oil and gas exploration operations. In fact, due to the combined tensile and torsional loads and the corrosive environment downhole, drill pipe cracking, leakage, and even breakage failures occur frequently, posing significant risks to drilling operations in oil and gas exploration and development. At best, these failures require additional manpower, resources, and funds for tripping the drill string or retrieving fish from the well, extending the drilling cycle and causing economic losses. At worst, they can lead to well filling and sidetracking, rendering part of the originally drilled well unusable, resulting in property damage and prolonged well construction delays.

[0005] Therefore, there is an urgent need to test and evaluate the rotational bending fatigue life of downhole tools such as drill pipe. Summary of the Invention

[0006] In view of the above problems, this application provides a bending and torsional fatigue testing device that can detect and evaluate the bending and torsional fatigue life of downhole tools such as drill pipes, and the structure of the testing device is simpler.

[0007] To achieve the above objectives, the embodiments of this application provide the following technical solutions:

[0008] In a first aspect, embodiments of this application provide a bending and torsional fatigue testing device, comprising:

[0009] The base has two arc-shaped tracks, which are symmetrically arranged on the base along a first direction;

[0010] Two loading components are movably connected to the two arc-shaped tracks, respectively, wherein one loading component is connected to one arc-shaped track; each loading component includes two loading elements, and the two loading elements move along the corresponding arc-shaped track in a direction that moves closer to or further away from each other;

[0011] The test piece is located between the two loading components, and each loading component is in direct contact with the test piece.

[0012] In some embodiments, the movement directions of the two loaders in one loading component are opposite to the movement directions of the two loaders in another loading component.

[0013] In some embodiments, each of the loading elements includes a rotating portion and a loading roller coaxially disposed on the rotating portion, the rotating portion rollingly contacting the corresponding arc-shaped track, and the loading roller being configured to rollingly contact the test piece.

[0014] In some embodiments, the rotating part is also coaxially provided with a track roller, and the rotating part makes rolling contact with the corresponding arc-shaped track through the track roller.

[0015] In some embodiments, the base includes two sub-bases, which are spaced apart along a second direction;

[0016] Each of the sub-bases is provided with two sub-arc-shaped tracks spaced apart along the first direction, and the two sub-arc-shaped tracks at the same height on the two sub-bases together form one arc track;

[0017] Furthermore, each of the rotating parts has two track rollers, and each of the rotating parts respectively makes rolling contact with the two corresponding sub-arc tracks through the two track rollers;

[0018] The second direction is perpendicular to the first direction.

[0019] In some embodiments, the bending and torsional fatigue testing device further includes a drive assembly connected to each of the loading members to drive the loading members to move along the corresponding arc-shaped track.

[0020] In some embodiments, the driving assembly includes four driving mechanisms, which are respectively connected to loading elements in two loading assemblies. Each driving mechanism corresponds to one loading element. Each driving mechanism includes a driving motor and a transmission structure. The driving motor is connected to the transmission structure, and the transmission structure is connected to the corresponding loading element to drive the loading element to move along the corresponding arc-shaped track.

[0021] In some embodiments, the transmission structure includes an eccentric wheel, the drive motor is connected to the eccentric wheel, and the eccentric wheel drives the corresponding loading member to move along the arc-shaped track; and / or,

[0022] The bending and torsional fatigue testing device also includes a stress testing piece, which is disposed on the test piece and is signal-connected to the drive motor. The drive motor selectively continues to run or stops running based on the test results of the stress testing piece.

[0023] In some embodiments, the bending and torsional fatigue testing device further includes two load compensation components, which are respectively disposed opposite to each other at both ends of the test piece;

[0024] Each load compensation component includes a fixing element and a strain compensation element, the strain compensation element being disposed between the fixing element and the test piece, and the fixing element being connected to the base.

[0025] In some embodiments, the bending and torsional fatigue testing device further includes a telescopic member disposed between the fixed member and the strain compensation member; and / or,

[0026] The outer diameter of the track roller is smaller than the width of the corresponding arc-shaped track, with a difference of 0.2mm to 0.6mm; and / or,

[0027] The surface of each of the said arc-shaped tracks has a wear-resistant layer; and / or,

[0028] Along the extension direction of the arc-shaped track, the arc-shaped track includes a straight segment and two arc-shaped segments, the two arc-shaped segments being symmetrically arranged on opposite sides of the straight segment and connected to the straight segment.

[0029] In this embodiment, a base and two loading components are provided, and two arc-shaped tracks are provided on the base. The two arc-shaped tracks are symmetrically arranged in a first direction. The two loading components are movably connected to the two arc-shaped tracks respectively, that is, one loading component is movably connected to one arc-shaped track. Each loading component includes two loading elements. The two loading elements in the loading component repeatedly move along the corresponding arc-shaped track on the base in a direction that approaches or moves away from each other. The test piece is located between the two loading components and is in direct contact with each loading element. In this way, when each loading element in the two loading components moves along the path of the corresponding arc-shaped track, the test piece is subjected to the force given by the loading element and undergoes bending and torsional deformation. The stress positions on the test piece will alternately experience tensile and compressive states, thereby achieving the effect of rotational bending and detecting the bending and torsional fatigue life of the test piece. Therefore, it is not necessary to separately set up components for driving the axial power, radial power and rotational power of the test piece, and the device structure is simple.

[0030] In addition to the technical problems solved by the embodiments of this application, the technical features constituting the technical solutions, and the beneficial effects brought about by the technical features of these technical solutions described above, other technical problems that can be solved by the bending and torsional fatigue testing device provided by the embodiments of this application, other technical features included in the technical solutions, and the beneficial effects brought about by these technical features will be further explained in detail in the specific implementation. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 is a schematic diagram of a bending and torsional fatigue testing device provided in an embodiment of this application;

[0033] Figure 2 is a partial schematic diagram of a transmission state cut at point AA in Figure 1;

[0034] Figure 3 is a partial schematic diagram of one operating state of the bending and torsional fatigue testing device in Figure 1.

[0035] Figure 4 is a partial schematic diagram of another operating state of the bending and torsional fatigue testing device in Figure 1.

[0036] Figure 5 is a schematic diagram of the eccentric wheel motion provided in an embodiment of this application;

[0037] Figure 6 is a schematic diagram of a motion state of the bending and torsional fatigue testing device for a test piece under single bending provided in an embodiment of this application.

[0038] Figure 7 is a schematic diagram of the bending and torsional fatigue testing device that can fix both ends of the test piece according to an embodiment of this application;

[0039] Figure 8 is a schematic diagram of the bending and torsional fatigue testing device that can be subjected to tensile loads according to an embodiment of this application.

[0040] Reference numerals: 10-Bending and torsional fatigue testing device; 100-Base; 101-First sub-base; 102-Second sub-base; 110-Arc-shaped track; 200-Loading assembly; 210-Loading component; 220-Rotating part; 230-Loading roller; 240-Railway roller; 221-First track roller; 222-Second track roller; 223-Snap ring; 300-Test piece; 310-Stress test piece; 400-Drive mechanism; 410-Drive motor; 420-Transmission structure; 421-Drive shaft; 422-Eccentric wheel; 423-Connecting rod; 500-Load compensation assembly; 510-Fixing component; 520-Strain compensation component; 530-Telescopic component. Detailed Implementation

[0041] In the exploration and development of oil and gas resources, downhole tools such as oil drill pipes provide torque to downhole rock-breaking tools (drill bits) through rotation during service. Simultaneously, constrained by the wellbore, the oil drill pipes are subjected to axial and radial forces, as well as rotational torque. Therefore, the oil drill pipes inevitably undergo elastic bending deformation, affecting their service life. Thus, there is an urgent need to test and evaluate the rotational bending fatigue life of downhole tools such as drill pipes. However, in related technologies, the devices used to test the rotational bending fatigue life of the test piece have complex structures. The test piece, in addition to the axial force from the axial component and the radial force from the radial component, also needs to be subjected to rotational force from the rotating component to achieve the rotational bending effect. Different structural components are required to provide the forces in different directions on the test piece, thus necessitating a solution to the problem of complex device structures.

[0042] To make the above-mentioned objectives, features, and advantages of the embodiments of this application more apparent and understandable, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0043] This application provides a bending and torsional fatigue testing device that can detect and evaluate the rotational bending fatigue life of downhole tools. The downhole tools include, but are not limited to, drill pipes and drill bits for use in downhole operations.

[0044] As shown in Figures 1 and 2, the base 100 of the bending and torsional fatigue testing device 10 has two arc-shaped tracks 110. The two arc-shaped tracks 110 are symmetrically arranged on the base 100 along a first direction. Two loading components 200 are movably connected to the two arc-shaped tracks 110 respectively. Each loading component 200 is connected to one arc-shaped track 110. Each loading component 200 includes two loading elements 210. The movement direction of the two loading elements 210 in one loading component 200 is opposite to the movement direction of the two loading elements 210 in the other loading component 200. The test piece 300 is located between the two loading components 200, and each loading element 210 is in direct contact with the test piece 300.

[0045] In some embodiments, an arc-shaped track 110 is provided on the base 100 to limit the movement path of the loading component 200 and to support the loading component 200. As shown in FIG1, one loading component 200 includes two loading elements 210, and another loading component 200 includes two more loading elements 210. The two loading elements 210 in the same loading component 200 move along the same arc-shaped track 110 on the base 100, and the movement directions of the loading elements 210 in the two loading components 200 are opposite. The movement directions of the two loading elements 210 in one loading component 200 are opposite to the movement directions of the two loading elements 210 in the other loading component 200, so that the two sides of the test piece 300 disposed between the two loading components 200 are subjected to different forces, thereby allowing the test piece 300 to undergo bending and torsional deformation, achieving the effect of rotational bending and torsion, and then the bending fatigue life of the test piece 300 is detected by the bending and torsional fatigue testing device 10.

[0046] In some embodiments, as shown in FIG3, when two loading members 210 in one loading assembly 200 move toward each other until the middle of the track, two loading members 210 in another loading assembly 200 move away from each other and simultaneously reach both ends of the track. Then, as shown in FIG4, the two loading members 210 that have reached the middle move away from each other until they reach both ends of the track, and the other two loading members 210 move toward each other and simultaneously reach the middle of the track. Each loading member 210 in the loading assembly 200 repeats the above movement on the arc track 110. The test piece 300 is subjected to the force given by the loading member 210 and undergoes bending and torsional deformation. Each force-bearing position on the test piece 300 will alternately experience tension and compression states, thereby achieving the effect of rotational bending and obtaining the bending and torsional fatigue life of the test piece 300.

[0047] In some embodiments, as shown in FIG1, two arc-shaped tracks 110 on the base 100 are symmetrically arranged on the base 100 along a first direction. The arc-shaped track 110 can be a full arc shape, which includes but is not limited to circular arcs and elliptical arcs. It can also be along the extension direction of the arc-shaped track 110. The arc-shaped track 110 includes a straight segment and two arc segments. The two arc segments are symmetrically arranged on opposite sides of the straight segment and connected to the straight segment. That is, the middle is a straight segment and the two sides are arc segments that are symmetrically distributed about the straight segment. The length of the middle straight segment is not less than the outer diameter of the loading roller 230 in the loading member 210. The full arc shape requires high processing accuracy. In contrast, the track shape of the middle straight segment and the two side arc segments can better place the test piece 300 between the two loading components during the working preparation stage of the bending and torsional fatigue testing device 10.

[0048] In some embodiments, the shape of the test piece 300 includes, but is not limited to, shaft-shaped or strip-shaped, and the testing device can detect and evaluate its bending and torsional fatigue life.

[0049] In this embodiment, in the bending and torsional fatigue testing device 10, the movement directions of two loading members 210 in one loading component 200 are opposite to those of two loading members 210 in another loading component 200. This causes the stress positions of the test piece 300 located between the two loading components 200 to alternate between tensile and compressive states, thereby achieving the effect of rotational bending to detect the bending and torsional fatigue life of the test piece 300. Furthermore, the bending and torsional fatigue testing device 10 in this embodiment does not require separate components for driving the axial, radial, and rotational forces of the test piece, resulting in a simple device structure. The base 100 of the bending and torsional fatigue testing device 10 includes two sub-bases, as shown in Figure 2. The two sub-bases are spaced apart along a second direction. Each sub-base has two sub-arc tracks spaced apart along a first direction. The two sub-arc tracks at the same height on the two sub-bases together form an arc track 110. Each rotating part 220 has two track rollers 240. Each rotating part 220 makes rolling contact with the corresponding two sub-arc tracks through the two track rollers 240. The second direction is perpendicular to the first direction.

[0050] In some specific embodiments, the base 100 includes a first sub-base 101 and a second sub-base 102, as shown in FIG2. The first sub-base 101 and the second sub-base 102 are distributed at intervals along a second direction. Two arc-shaped tracks 110 are provided on the base 100. Each arc-shaped track 110 includes two sub-arc-shaped tracks at the same height as the first sub-base 101 and the second sub-base 102, as shown in FIG1. ​​The two arc-shaped tracks 110 are symmetrically distributed along a first direction.

[0051] In some embodiments, the rotating part 220 can be a circular shaft, and the rotating part 220 has a track roller 240. The track roller 240 includes a first track roller 221 and a second track roller 222. The rotating part 220 rolls in contact with the first sub-base 101 through the first track roller 221, and rolls in contact with the second sub-base 102 through the second track roller 222. The friction generated by the rolling motion of the rotating part 220 with the arc track 110 through the track roller 240 is less than the friction generated by the motion through the direct contact between the rotating part 220 and the arc track 110.

[0052] In some embodiments, because the track roller 240 is in rolling connection with the arc track 110 on the base 100, the surfaces of the two arc tracks 110 on the base 100 are both treated with wear-resistant materials so that the surface of each arc track 110 has a wear-resistant layer. The wear-resistant treatment methods include, but are not limited to, surface hardening, plating, spraying, etc., to reduce the wear between the loading component 200 and the arc track 110 so as not to affect the accuracy of the testing device.

[0053] As shown in Figures 1 and 2, the loading member 210 on the bending and torsional fatigue testing device 10 includes a rotating part 220 and a loading roller 230 coaxially disposed on the rotating part 220. The rotating part 220 rolls in contact with the corresponding arc track 110, and the loading roller 230 is configured to roll in contact with the test piece 300.

[0054] Furthermore, a track roller 240 is coaxially arranged on the rotating part 220, and the rotating part 220 makes rolling contact with the corresponding arc-shaped track 110 through the track roller 240.

[0055] In some embodiments, as shown in FIG2, the loading member 210 includes a rotating part 220, a first track roller 221, a second track roller 222, a loading roller 230, and a retaining ring 223. The retaining ring 223 has the function of reducing the movement resistance of the loading roller 230 and enhancing the stability of the loading roller 230 moving along the arc track. The rolling of the loading member 210 along the corresponding arc track 110 drives the loading roller 230 to move in an arc. The loading roller 230 is in direct contact with the test piece 300. Therefore, the loading roller 230 rolls relative to the test piece 300, and the test piece 300 is subjected to bending and twisting deformation by the force directly applied by the loading member 210.

[0056] In some embodiments, considering error requirements, the outer diameter of the track roller 240 is smaller than the width of the corresponding arc track 110. Alternatively, a grooved track can be provided on the track roller 240, in which case the grooved portion of the track roller 240 rolls on the arc track 110, and the outer diameter of the grooved portion of the track roller 240 is smaller than the width of the corresponding arc track 110.

[0057] In some embodiments, the difference between the outer diameter of the track roller 240 or the outer diameter of the groove portion of the track roller 240 with the grooved track and the width of the corresponding arc track 110 is 0.2mm to 0.6mm, for example, 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm, etc.

[0058] In some embodiments, the outer diameter of the loading roller 230 is not less than the outer diameter of the track roller 240. When the placement distance of the test piece 300 between the two loading components 200 remains unchanged, the outer diameter of the loading roller 230 being greater than or equal to the outer diameter of the track roller 240 can increase the distance between the two arc-shaped tracks, ensuring that the base portion between the two arc-shaped tracks has sufficient support strength. If the outer diameter of the loading roller 230 is less than the outer diameter of the track roller 240, the distance between the loading rollers 230 on the two arc-shaped tracks is greater than the distance between the track rollers 240. For a small-sized test piece 300, this may result in less constraint of the loading component 210 on the test piece 300, which may affect the bending and torsional fatigue test results of the test piece 300.

[0059] In some embodiments, the bending and torsional fatigue testing device 10 can perform bending and torsional fatigue testing on the test piece 300 under different bending degrees by replacing the loading rollers 230 with different outer diameters.

[0060] The bending and torsional fatigue testing device 10 also includes a drive assembly, which is connected to each loading member 210 to drive the loading member 210 to move along the corresponding arc track 110.

[0061] The driving component drives the two loading elements 210 in each loading component 200 to move towards each other or away from each other. The test piece 300, which is in rolling contact with each loading element 210, is subjected to bending and torsional deformation, thereby obtaining the bending and torsional fatigue life of the test piece 300.

[0062] As shown in Figure 2, the drive assembly includes four drive mechanisms 400, which are respectively connected to the loading elements 210 in the two loading assemblies 200. Each drive mechanism 400 corresponds to one loading element 210. Each drive mechanism 400 includes a drive motor 410 and a transmission structure 420. The drive motor 410 is connected to the transmission structure 420, and the transmission structure 420 is connected to the corresponding loading element 210 to drive the loading element 210 to move along the corresponding arc track 110.

[0063] In some embodiments, the drive assembly is connected to each loading member 210. The drive assembly includes four drive mechanisms 400. Each drive mechanism 400 includes a drive motor 410 and a transmission structure 420. The drive motor 410 serves as the power device for the entire test device. Through the transmission structure 420, it converts electrical energy into kinetic energy for the loading member 210 to move along the corresponding arc track 110. Alternatively, the transmission structure 420 can be driven manually.

[0064] In some embodiments, four drive motors 410 can be used to drive the loading member 210 to move along the arc-shaped track by moving along the arc-shaped rack, wherein the second track roller 222 of the loading member is replaced by a gear that matches the rack. Alternatively, one drive motor 410 can be used to drive one driving wheel, which meshes with the driven wheel. Two loading members mesh with the driving wheel, and the other two loading members mesh with the driven wheel, thereby driving the loading assembly to move along the arc-shaped track. In this case, the second track roller 222 of the loading member is replaced by a gear that matches the driving wheel and the driven wheel respectively.

[0065] The transmission structure 420 includes an eccentric wheel 422, and the drive motor 410 is connected to the eccentric wheel 422. The eccentric wheel 422 drives the corresponding loading member 210 to move along the arc track 110.

[0066] In some embodiments, as shown in Figures 2 and 5, the transmission structure 420 includes a transmission shaft 421, an eccentric wheel 422, and a connecting rod 423. The two ends of the transmission shaft 421 are connected to the drive motor 410 and the eccentric wheel 422, respectively. The two ends of the connecting rod 423 are connected to the eccentric wheel 422 and the loading member 210, respectively. The drive motor 410 drives the eccentric wheel 422 to rotate through the transmission shaft 421, thereby driving the connecting rod 423 and the loading member 210 connected to the other end of the connecting rod to move along the arc track 110.

[0067] For example, the drive motor 410 has a drive shaft, which is fixedly connected to the transmission shaft 421, the transmission shaft 421 is fixedly connected to the eccentric wheel 422, and the connecting rod 423 is fixedly connected to the rotating part 220. The fixed connection methods include, but are not limited to, welding, bonding, and snap-fit ​​connection. The connecting rod 423 is rotatably connected to the eccentric wheel, and the rotatable connection method can be a hole-shaft mating connection.

[0068] The bending and torsional fatigue testing device 10 also includes a stress test piece 310, which is disposed on the test piece 300. The stress test piece 310 is connected to the drive motor 410 by signal. The drive motor 410 selectively continues to run or stops running according to the test result of the stress test piece 310.

[0069] In some embodiments, the stress test piece 310 can be a sensor for detecting the strain signal of the test piece 300. It is placed on the upper side or bottom of the middle part of the test piece 300. When the drive motor 410 is started, the test piece 300 undergoes bending and torsional deformation. The stress test piece 310 transmits the strain signal to the signal testing device through the signal line, and the signal testing device converts the strain signal into the corresponding tensile stress. The signal detection device then transmits the tensile stress to the drive motor 410 through the signal line. When the tensile stress is detected to reach the set fixed value, the drive motor 410 stops running. When the tensile stress is detected to not reach the set fixed value, but the drive motor stops running, it can be selected to let the drive motor continue to run.

[0070] In some embodiments, the drive motor 410 can be started and stopped by a controller. The controller can display the strain signal transmitted from the stress test piece 310 and the tensile stress data converted by the signal testing device, and can control the start and stop of the drive motor 410. The stress test piece 310 transmits the strain signal to the signal testing device through a signal line. The testing device is connected to the controller, and the controller is then connected to the drive motor for operation. This can increase the human monitoring and control of the start and stop of the drive motor. Furthermore, a fixed value of tensile stress can be set on the controller so that when the tensile stress of the test piece 300 reaches the set fixed value, the drive motor 410 stops running.

[0071] In some embodiments, as shown in FIG6, two loading members 210 of one loading component 200 of the bending and torsional fatigue testing device 10 are placed in the middle of the track, and the drive motors 410 corresponding to the two loading members 210 are kept in a stopped state. The drive motors 410 corresponding to the two loading members 210 in the other loading component 200 are started. The two loading members 210 move back to back to the positions at both ends of the arc track 110, and then move towards each other to the position in the middle of the arc track 110. The above movement is repeated continuously, and the test piece 300 repeats the bending deformation and recovery state in the same direction until the tensile stress transmitted by the stress test piece 310 reaches the set value. The corresponding two drive motors 410 stop running, so that the bending and torsional fatigue test of the test piece 300 can be performed on a single bending.

[0072] The bending and torsional fatigue testing device 10 also includes two load compensation components 500, which are respectively disposed opposite to each other at both ends of the test piece 300. Each load compensation component 500 includes a fixing member 510 and a strain compensation member 520. The strain compensation member 520 is disposed between the fixing member 510 and the test piece 300. The fixing member 510 is connected to the base 100.

[0073] In some embodiments, as shown in FIG7, two fixing members 510 and two strain compensation members 520 are added to the bending and torsional fatigue testing device 10. The fixing members 510 are fixedly connected to the first sub-base 101, and the two ends of the strain compensation members 520 are respectively connected to the fixing members 510 and the test piece 300. When the loading member 210 moves along the arc track 110, the test piece 300 is not only subjected to bending and torsional deformation by the force given by the loading member 210, but also passively subjected to the axial tensile force generated by the fixing of the two ends because the fixing members 510 are fixed to the first sub-base 101. Thus, the bending and torsional fatigue test of the two ends of the test piece 300 can be realized.

[0074] The bending and torsional fatigue testing device 10 also includes a telescopic member 530, which is disposed between the fixing member 510 and the strain compensation member 520.

[0075] In some embodiments, as shown in FIG8, two fixing members 510, two strain compensation members 520, and two telescopic members 530 are added to the bending and torsional fatigue testing device 10. The fixing members 510 are fixedly connected to the first sub-base 101. The two ends of the telescopic members 530 are connected to the fixing members 510 and the strain compensation members 520 respectively. The two ends of the strain compensation members 520 are connected to the telescopic members 530 and the test piece 300 respectively. The telescopic members 530 can give the test piece 300 an additional axial force. When the loading member 210 moves along the arc track 110, the test piece 300 is not only subjected to the force given by the loading member 210 and undergoes bending and torsional deformation, but also subjected to the axial force given by the telescopic members 530. This can realize the bending and torsional fatigue test of applying tensile load to the test piece 300.

[0076] In some embodiments, the fixing connection between the above-mentioned fastener 510 and the first sub-base 101 includes, but is not limited to, welding, pin hole fixing, threaded connection, etc. The strain compensation member 520 is used to compensate for the axial displacement and radial position of the test piece 300, including, but not limited to, springs. The telescopic member 530 applies an axial tensile load to the test piece 300, including, but not limited to, hydraulic telescopic members. The magnitude of the axial force applied to the test piece 300 by the telescopic member can be controlled manually or by program.

[0077] For example, the fastener 510 is fixedly connected to the telescopic member 530, the telescopic member 530 is fixedly connected to the strain compensation member 520, and the strain compensation member 520 is fixedly connected to the test piece 300. The fixed connection methods include, but are not limited to, welding, bonding, and snap-fit ​​connection.

[0078] The various embodiments or implementation methods described in this specification are presented in a progressive manner. Each embodiment focuses on the differences from other embodiments, and the same or similar parts between the embodiments can be referred to each other.

[0079] It should be noted that the terms "one embodiment," "embodiment," "exemplary embodiment," "some embodiments," etc., mentioned in the specification indicate that the described embodiment may include a specific feature, structure, or characteristic, but not every embodiment necessarily includes that specific feature, structure, or characteristic. Furthermore, such phrases do not necessarily refer to the same embodiment. Moreover, when a specific feature, structure, or characteristic is described in connection with an embodiment, implementing such a feature, structure, or characteristic in conjunction with other embodiments, whether explicitly described or not, is within the knowledge scope of those skilled in the art.

[0080] Generally speaking, terms should be understood at least in part by their use in context. For example, at least in part by context, the term "one or more" as used in the text can be used to describe any feature, structure, or characteristic of the singular meaning, or a combination of features, structures, or characteristics of the plural meaning. Similarly, at least in part by context, terms such as "a" or "the" can also be understood to convey either singular or plural usage.

[0081] It should be readily understood that the terms “on,” “above,” and “on top of” in this application should be interpreted in the broadest possible sense, such that “on” means not only “directly on something” but also “on something” with an intermediate feature or layer therebetween, and that “above” or “on top of” means not only “on top of something” but also “on top of something” without an intermediate feature or layer therebetween (i.e., directly on something).

[0082] Furthermore, for ease of explanation, spatially relative terms such as "below," "below," "under," "above," and "above" may be used to describe the relationship of one element or feature relative to other elements or features as shown in the figures. Spatially relative terms are intended to encompass different orientations of the device in use or operation other than those shown in the figures. The device may have other orientations (rotated 90° or in other orientations), and the spatially relative descriptive terms used herein may be interpreted accordingly.

[0083] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A bending and torsional fatigue testing device, characterized in that, include: The base (100) has two arc-shaped tracks (110), which are symmetrically arranged on the base (100) along a first direction; Two loading components (200) are movably connected to two arc-shaped tracks (110), wherein one loading component (200) is connected to one arc-shaped track (110); each loading component (200) includes two loading elements (210), and the two loading elements (210) move along the corresponding arc-shaped track (110) in a direction that approaches or moves away from each other; The test piece (300) is located between the two loading components (200), and each loading component (210) is in direct contact with the test piece (300).

2. The bending and torsional fatigue testing device according to claim 1, characterized in that, The movement directions of two of the loading elements (210) in one loading assembly (200) are opposite to the movement directions of two of the loading elements (210) in the other loading assembly (200).

3. The bending and torsional fatigue testing device according to claim 1 or 2, characterized in that, Each of the loading elements (210) includes a rotating part (220) and a loading roller (230) coaxially disposed on the rotating part (220). The rotating part (220) rolls in contact with the corresponding arc track (110), and the loading roller (230) is configured to roll in contact with the test piece (300).

4. The bending and torsional fatigue testing device according to claim 3, characterized in that, The rotating part (220) is also coaxially provided with a track roller (240), and the rotating part (220) makes rolling contact with the corresponding arc-shaped track (110) through the track roller (240).

5. The bending and torsional fatigue testing device according to claim 4, characterized in that, The base (100) includes two sub-bases, which are spaced apart along a second direction; Each of the sub-bases is provided with two sub-arc tracks spaced apart along the first direction, and the two sub-arc tracks at the same height on the two sub-bases together form one arc track (110); Each of the rotating parts (220) has two track rollers (240), and each of the rotating parts (220) makes rolling contact with the corresponding two sub-arc tracks through the two track rollers (240); The second direction is perpendicular to the first direction.

6. The bending and torsional fatigue testing device according to claim 1 or 2, characterized in that, The bending and torsional fatigue testing device (10) further includes a driving component, which is connected to each of the loading members (210) to drive the loading members (210) to move along the corresponding arc track (110).

7. The bending and torsional fatigue testing device according to claim 6, characterized in that, The driving assembly includes four driving mechanisms (400), which are respectively connected to the loading elements (210) in the two loading assemblies (200). Each driving mechanism (400) corresponds to one loading element (210). Each driving mechanism (400) includes a driving motor (410) and a transmission structure (420). The driving motor (410) is connected to the transmission structure (420), and the transmission structure (420) is connected to the corresponding loading element (210) to drive the loading element (210) to move along the corresponding arc track (110).

8. The bending and torsional fatigue testing device according to claim 7, characterized in that, The transmission structure (420) includes an eccentric wheel (422), the drive motor (410) is connected to the eccentric wheel (422), and the eccentric wheel (422) drives the corresponding loading member (210) to move along the arc-shaped track (110); and / or, The bending and torsional fatigue testing device (10) also includes a stress testing piece (310), which is disposed on the test piece (300). The stress testing piece (310) is connected to the drive motor (410) by signal. The drive motor (410) selectively continues to run or stops running according to the test result of the stress testing piece (310).

9. The bending and torsional fatigue testing device according to claim 4, characterized in that, The bending and torsional fatigue testing device also includes two load compensation components (500), which are respectively disposed opposite to each other at both ends of the test piece (300); Each of the load compensation components (500) includes a fixing member (510) and a strain compensation member (520), the strain compensation member (520) being disposed between the fixing member (510) and the test piece (300), and the fixing member (510) being connected to the base (100).

10. The bending and torsional fatigue testing device according to claim 9, characterized in that, The load compensation assembly (500) further includes a telescopic member (530) disposed between the fixing member (510) and the strain compensation member (520); and / or, The outer diameter of the track roller (240) is smaller than the width of the corresponding arc-shaped track (110), with a difference of 0.2 mm to 0.6 mm; and / or, The surface of each of the said arc-shaped tracks (110) has a wear-resistant layer; and / or, Along the extending direction of the arc-shaped track (110), the arc-shaped track (110) includes a straight segment and two arc segments, the two arc segments being symmetrically arranged on opposite sides of the straight segment and connected to the straight segment.

Images