A Hopkinson torsion bar test equipment

Abstract

The present invention relates to the technical field of experimental equipment, and more specifically, to a Hopkinson torsion bar experimental equipment, comprising: a clamping and releasing device disposed on a guide support and capable of clamping an incident rod in a circumferential direction; the clamping and releasing device comprising a clamping assembly, a transmission rod, and a driving assembly, wherein two clamping assemblies are provided and mirror-imaged on either side of the incident rod; the clamping assembly comprises a clamping claw and a connecting rod, wherein the clamping claw is disposed at a first end of the connecting rod, the middle portion of the connecting rod is hinged to the guide support, and the second end of the connecting rod is provided with a guide rail; the two ends of the transmission rod are capable of sliding along the guide rail, and the driving assembly is capable of driving the connecting rod to move in a vertical direction; the driving assembly is capable of driving the connecting rod toward or away from the incident rod, so that the clamping and releasing device can switch between a clamped state and a released state. This solves the problems of the inability to accurately control the clamping force of the clamping and releasing device, poor repeatability, and high experimental costs during the Hopkinson torsion bar experiment.

Description

Technical Field

[0001] The present invention relates to the technical field of experimental equipment, in particular to a Hopkinson torsion bar experimental equipment. Background Art

[0002] The Hopkinson torsion bar is an experimental device used to study the dynamic mechanical properties of materials under high-speed torsion. It primarily consists of a torque loading device, a clamping and releasing mechanism, a torsion bar incident rod, and a transmission rod. The transmission rod can also be replaced with a rigid support for laboratory applications in earthquake fault friction, material friction, and wear. Traditional high-speed friction devices use a high-power servo motor through a gear / belt transmission system to apply high-speed rotational shear forces to the specimen. However, these devices can only achieve high-speed rotation under relatively low axial pressures. High axial pressures require higher torque to activate, placing higher demands on the torque loading system. The Hopkinson torsion bar, based on the Hopkinson bar principle, utilizes stress wave propagation within the bar to simulate the stress state of materials during high-speed torsion. Research began in the 1970s, and various loading methods have subsequently emerged, including pre-stored energy, explosive, flywheel, and electromagnetic loading methods. However, the pre-stored energy method is the most widely used.

[0003] In the pre-energy-storage split-Hopkinson torsion bar experiment, the specimen is fixed between a rotatable incident rod and a transmission rod. The incident rod is split into two sections by a clamp-release mechanism: the section away from the specimen serves as the energy storage section, while the other section is prevented from twisting by the clamp-release mechanism. The fundamental requirement for the clamp-release mechanism is that the torsion bar reliably clamps and transiently releases when an external torque is applied to the energy storage section. When the clamp-release mechanism clamps the incident rod, the energy storage section stores energy under the applied torque. Once the predetermined value is reached, the clamp-release mechanism suddenly releases. The stored energy in the energy storage section rapidly propagates through the rod as a torsional wave, acting on the specimen and generating corresponding torsional strain. By measuring and analyzing the propagation of the stress wave and the strain response of the specimen, mechanical parameters of the material under high-speed torsion, such as shear strength and shear modulus, can be determined.

[0004] The torque loading device and clamping release mechanism are the core components of a Hopkinson torsion bar. Traditional Hopkinson torsion bars utilize a wide variety of torque loading mechanisms. Some include a hydraulic system, a limit plate, a gear belt, a gear plate, and a sleeve. A gear belt secured to a support meshes with a gear plate positioned within a sleeve on the energy storage section of the incident rod, thereby applying torque to the energy storage rod and storing energy. However, these mechanisms only provide intermittent motion in one direction, making it difficult to precisely control the angle of rotation. Direct impact loading, such as explosive loading, directly impacts the free end of the rod, inevitably generating bending waves that affect test accuracy. Stepper motors are also used as torque loading mechanisms. While stepper motors offer advantages such as ease of control, compact size, and low cost, they struggle to achieve high torque. Low-frequency oscillations can occur during low-speed rotation, resulting in long-term speed instability. High-load operation can also lead to motor overheating, impacting performance and lifespan.

[0005] The clamping and release mechanism of a conventional Hopkinson torsion bar primarily consists of two joined semicircular bridge arms and a slotted bolt. Adjusting the tightening of the slotted bolt provides the necessary clamping force for the energy storage section. However, in practical applications, when the accumulated energy stored in the energy storage section reaches the predetermined experimental value, the slotted bolt must be cut to release the clamp. This clamping and release mechanism and its operation method present significant shortcomings. First, during the clamping force application process, insufficient clamping force often leads to continued tightening of the slotted bolt, which can easily break due to overtightening, resulting in experimental failure. Alternatively, when the slotted bolt needs to be cut to release the clamp, the timing of the cut is often difficult to precisely control, resulting in significant uncertainty and poor experimental repeatability. This not only reduces experimental efficiency but also significantly limits the further development and widespread application of split-Hopkinson torsion bar technology. Furthermore, from a cost perspective, each torque release requires cutting a slotted bolt, and the time-consuming replacement of each slotted bolt after each test significantly increases experimental costs. Summary of the Invention

[0006] In order to solve the problems that the clamping force of the clamping and releasing device cannot be accurately controlled, the repeatability is poor, and the experimental cost is high during the Hopkinson torsion bar experiment, the present invention provides a Hopkinson torsion bar experimental equipment, comprising: a torsion bar device, a loading device, a supporting device and a clamping and releasing device; the torsion bar device comprises a fixing assembly and an incident rod, the test sample is clamped between the fixing assembly and the incident rod, the loading device is used to drive the torsion bar device to apply a force to the test sample, the supporting device comprises a guide support, the guide support is provided with a first through hole arranged along the extending direction of the incident rod, the incident rod can pass through the first through hole, the clamping and releasing device is arranged on the guide support and can clamp the incident rod in the circumferential direction, the loading device can The invention can drive the incident rod to rotate; the clamping and releasing device includes a clamping assembly, a transmission rod and a driving assembly. Two clamping assemblies are provided and are mirror-imaged on both sides of the incident rod. The clamping assembly includes a clamping claw and a connecting rod. The clamping claw is provided at the first end of the connecting rod, the middle part of the connecting rod is hinged on the guide support, and the second end of the connecting rod is provided with a guide rail; the two ends of the transmission rod can slide along the guide rail, and the driving assembly can drive the connecting rod to move in the vertical direction; the clamping and releasing device includes a clamping state in which the clamping claw is tightly attached to the outer circumference of the incident rod, and a releasing state in which there is a gap between the clamping claw and the outer circumference of the incident rod; the driving assembly can drive the connecting rod close to or away from the incident rod, so that the clamping and releasing device can switch between the clamping state and the releasing state.

[0007] In some embodiments, the clamp includes an arc-shaped piece and a hinge seat arranged at the first end of the connecting rod. The arc-shaped piece can be fitted on the outer peripheral surface of the incident rod. The arc-shaped piece is hinged on the hinge seat and can rotate in the vertical direction. The arc radius of the inner surface of the arc-shaped piece is less than or equal to the radius of the incident rod.

[0008] In some embodiments, the clamping release device further includes an elastic member, which is disposed between the two connecting rods. When the clamping release device switches from a release state to a clamping state, the elastic member is gradually stretched and elastically deformed.

[0009] In some embodiments, the driving assembly includes a hydraulic cylinder having a telescopic end that can move closer to or farther away from the incident rod, and the telescopic end is connected to the transmission rod.

[0010] In some embodiments, the support device further comprises a base plate, a plurality of guide supports being fixed to the base plate and provided, the plurality of guide supports being sequentially spaced along the length of the base plate. In some embodiments, the guide support comprises a lower base body and an upper base body, the lower base body having a first groove formed at a top thereof, the upper base body having a second groove corresponding to the first groove, the upper base body being fixed to the lower base body such that the first groove and the second groove are combined to form a first through hole; a radial bearing is provided in the first through hole.

[0011] In some embodiments, the loading device includes a thrust assembly and a torsion assembly, which are respectively connected to the two ends of the torsion bar device. The thrust assembly can push the torsion bar device in the axial direction to apply axial pressure to the test sample, and the torsion assembly can twist the incident rod to rotate.

[0012] In some embodiments, the thrust assembly is connected to the fixed assembly, and the torsion assembly is connected to the incident rod; the support device also includes a rigid support fixed to the base plate, the rigid support is arranged at one end of the incident rod close to the torsion assembly, and the rigid support and the guide support are spaced apart along the extension direction of the incident rod; the rigid support is provided with a second through hole, and a thrust bearing is provided in the second through hole.

[0013] In some embodiments, the fixing assembly includes a fixing groove for arranging the test sample, the fixing groove is arranged along the extension direction of the incident rod, and a measuring sensor is arranged on the outer side of the fixing groove.

[0014] In some embodiments, the loading device further includes a sensor assembly, the sensor assembly including a torque sensor and a sensor bracket, the torque sensor is disposed between the incident rod and the torsion assembly, and the sensor bracket is fixed to the base plate and connected to the torque sensor.

[0015] To solve the problems of the inability to accurately control the clamping force of the clamping release device, poor repeatability, and high experimental cost during the Hopkinson torsion bar experiment, the present invention has the following advantages:

[0016] In the above technical solution, the driving assembly is used to push the transmission rod towards or away from the incident rod that needs to be clamped, so as to push the connecting rod to rotate, thereby driving the clamping claws set on the connecting rod to clamp or release the incident rod. At the same time, by controlling the sliding distance of the transmission rod or the distance from the incident rod, the clamping force of the clamping assembly when clamping the incident rod can be controlled more accurately, and the control variables in the adjustment process are relatively single, so that the control process has high repeatability, which is conducive to improving the consistency of multiple tests and making the experimental process more accurately reproduced. It also eliminates the need for the setting of disposable and difficult to accurately control components such as slotted bolts, so that when the incident rod needs to be released, it is only necessary to directly control the driving device, which reduces the uncertainty of the test, improves the experimental efficiency, and reduces the test cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A schematic structural diagram of a Hopkinson torsion bar test apparatus according to an embodiment is shown;

[0018] Figure 2 Shown Figure 1 A schematic diagram of the enlarged structure of the middle part A;

[0019] Figure 3A structural schematic diagram of a rigid support according to an embodiment is shown;

[0020] Figure 4 A schematic structural diagram of a Hopkinson torsion bar experimental device according to another embodiment is shown.

[0021] Figure markings: 11-fixing assembly; 12-incident rod; 21-thrust assembly; 22-torque assembly; 23-sensor assembly; 30-support device; 31-guide support; 311-upper seat; 312-lower seat; 313-radial bearing; 32-rigid support; 321-thrust bearing; 33-pull rod; 34-base; 40-clamping release device; 411-clamping claw; 4111-arc-shaped piece; 4112-articulated seat; 412-connecting rod; 4121-guide rail; 43-drive assembly; 44-elastic member. DETAILED DESCRIPTION

[0022] The present disclosure will now be discussed with reference to several exemplary embodiments. It should be understood that these embodiments are discussed only to enable those skilled in the art to better understand and implement the present disclosure, rather than to imply any limitation on the scope of the present disclosure.

[0023] As used herein, the term "including" and its variations are to be interpreted as open-ended terms meaning "including, but not limited to." The term "based on" is to be interpreted as "based, at least in part, on." The terms "one embodiment" and "an embodiment" are to be interpreted as "at least one embodiment." The term "another embodiment" is to be interpreted as "at least one other embodiment." Terms such as "upper," "lower," "left," "right," "front," "back," "top," "bottom," "inner," "outer," "vertical," "horizontal," "transverse," and "longitudinal" indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. These terms are primarily intended to better describe the present application and its embodiments and are not intended to limit the devices, elements, or components indicated to having a specific orientation, or to being constructed and operated in a specific orientation. Furthermore, some of the above terms may be used to indicate other meanings besides orientation or positional relationships. For example, the term "on" may, in certain circumstances, be used to indicate a dependency or connection relationship. Those skilled in the art will understand the specific meanings of these terms in this application based on the specific circumstances. Furthermore, the terms "installed," "disposed," "provided with," "connected," and "connected" are to be interpreted broadly. For example, it can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection or an electrical connection; it can be a direct connection, an indirect connection through an intermediate medium, or an internal connection between two devices, elements, or components. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to the specific circumstances. In addition, the terms "first", "second", etc. are mainly used to distinguish different devices, elements, or components (the specific types and structures may be the same or different), and are not used to indicate or imply the relative importance or quantity of the indicated devices, elements, or components. Unless otherwise specified, "plurality" means two or more.

[0024] This embodiment discloses a Hopkinson torsion bar test device, such as Figure 1-2As shown, it may include: a torsion bar device, a loading device, a support device 30 and a clamping release device 40; the torsion bar device includes a fixing assembly 11 and an incident rod 12, the test sample is clamped between the fixing assembly 11 and the incident rod 12, the loading device is used to drive the torsion bar device to apply a force to the test sample, the support device 30 includes a guide support 31, the guide support 31 is provided with a first through hole provided along the extending direction of the incident rod 12, the incident rod 12 can pass through the first through hole, the clamping release device 40 is provided on the guide support 31 and can clamp the incident rod 12 in the circumferential direction, and the loading device can drive the incident rod 12 to rotate; the clamping release device 40 includes a clamping assembly, a transmission rod and a driving assembly 43, the clamping assembly is provided with two And the mirror images are arranged on both sides of the incident rod 12, the clamping assembly includes a clamping jaw 411 and a connecting rod 412, the clamping jaw 411 is arranged at the first end of the connecting rod 412, the middle part of the connecting rod 412 is hinged on the guide support 31, and the second end of the connecting rod 412 is provided with a guide rail 4121; the two ends of the transmission rod can slide along the guide rail 4121, and the driving assembly 43 can drive the connecting rod 412 to move in the vertical direction; the clamping release device 40 includes a clamping state in which the clamping jaw 411 is tightly clamped to the outer peripheral surface of the incident rod 12, and a release state in which there is a gap between the clamping jaw 411 and the outer peripheral surface of the incident rod 12; the driving assembly 43 can drive the connecting rod 412 close to or away from the incident rod 12, so that the clamping release device 40 can switch between the clamping state and the release state.

[0025] It should be noted that in the Hopkinson torsion bar test, both a torsional force and an axial thrust are applied to the test sample simultaneously. Generally speaking, the test sample may include two subsamples, one of which is fixed to the fixing assembly 11 and the other to the incident rod 12. During the experiment, the incident rod 12 can drive one of the subsamples to rotate. The torsional waves generated during this process are transmitted to the test sample through the incident rod 12, thereby generating corresponding torsional strain. Therefore, during the test, the incident rod 12 must first be fixed before applying a rotational torque to it, causing it to elastically deform and accumulate energy.

[0026] In the above technical solution, the driving assembly 43 is used to push the transmission rod towards or away from the incident rod 12 that needs to be clamped, so as to push the connecting rod 412 to rotate, thereby driving the clamping claw 411 set on the connecting rod 412 to clamp or release the incident rod 12. At the same time, by controlling the sliding distance of the transmission rod or the distance from the incident rod 12, the clamping force of the clamping assembly when clamping the incident rod 12 can be controlled more accurately, and the control variables in the adjustment process are relatively single, so that the control process has high repeatability, which is conducive to improving the consistency of multiple tests and making the experimental process more accurately reproduced. It also eliminates the setting of disposable and difficult to accurately control components such as slotted bolts, so that when the incident rod 12 needs to be released, it is only necessary to directly control the driving device, which reduces the uncertainty of the test, improves the experimental efficiency, and reduces the test cost.

[0027] The fixing assembly 11 may include a transmission rod, and the subsample may be fixed to the side of the transmission rod facing the incident rod 12. The fixing method can be selected appropriately according to the situation; specifically, AB-type epoxy resin is preferably used for bonding. Similarly, the subsample may be bonded to one end of the incident rod 12. The incident rod 12 may be a solid round rod, so that torsional waves of different frequencies propagate at the same speed without frequency dispersion. The guide support 31 is provided to secure the incident rod 12 at an appropriate height. The connecting rod 412 also provides a fixed attachment point for rotation. Of course, it is understood that the connecting rod 412 can also be attached to a separate bracket to achieve the same effect. However, hinged connection to the guide support 31 reduces the number of parts and simplifies the equipment. The clamping jaw 411 can be a simple sheet, block, or contoured jaw with a shape similar to the outer circumference of the incident rod 12, or a more complex manipulator with movable joints and a drive mechanism, as long as it can fully clamp the incident rod 12. Connecting rod 412 is made of a hard material and has high mechanical strength to resist deformation caused by applied forces. Connecting rod 412 can be hinged or connected by means of a pin connection. Since the hinged components need to be fixed while also bearing shear forces, they can be made of high-quality carbon steel that has undergone appropriate heat treatment. This material has high strength, high wear resistance, high corrosion resistance, and good overall mechanical properties. Sliding blocks or other structures that match guide rail 4121 can be provided at both ends of the transmission rod, or sliding bearing nodes can be used as a specific implementation. The sliding bearing nodes can ensure that the transmission rod can slide along guide rail 4121 and reduce friction between the transmission rod and guide rail 4121 during the sliding process. Furthermore, the transmission rod will rotate relative to connecting rod 412 during the sliding process, and the sliding bearing nodes can prevent this rotation from occurring, making the structure more flexible in force transmission. Furthermore, since guide rail 4121 and the sliding bearing node are theoretically in infinitesimal line contact, pressure transmission can only be achieved when the sliding bearing node and the guide rail 4121 wall deform and form surface contact. Therefore, it is important to ensure that the metal material used does not undergo plastic deformation and failure due to extrusion and slippage, and has sufficient rigidity and strength to withstand the loads and impacts during operation. Drive assembly 43 can be a mechanical structure such as an electric motor, a pneumatic cylinder, or a hydraulic cylinder.

[0028] In addition, the length of the guide rail 4121 can be determined according to the following formula:

[0029] ;

[0030] Among them, α0 is the angle between the transmission rod and the connecting rod 412 when the clamping release device 40 is in the released state; α2 is the angle between the transmission rod and the connecting rod 412 when the clamping release device 40 is in the clamped state; l1 is the distance between the far end of the guide rail 4121 and the hinge point of the connecting rod 412; r is the radius of the sliding bearing node installed at the end of the transmission rod.

[0031] At the same time, the angle α between the transmission rod and the connecting rod 412 and the stroke h of the transmission rod satisfy the following relationship:

[0032] ;

[0033] Wherein, α0 is the angle between the transmission rod and the connecting rod 412 when the clamping release device 40 is in the released state; l1 is the distance between the distal end of the guide rail 4121 and the hinge point of the connecting rod 412;

[0034] As a specific implementation method, Figure 2 As shown, the clamping jaw 411 includes an arc-shaped piece 4111 and a hinge seat 4112 arranged at the first end of the connecting rod 412. The arc-shaped piece 4111 can be attached to the outer peripheral surface of the incident rod 12. The arc-shaped piece 4111 is hinged on the hinge seat 4112 and can rotate in the vertical direction; the arc radius of the inner surface of the arc-shaped piece 4111 is less than or equal to the radius of the incident rod 12.

[0035] The provision of the arcuate piece 4111 can increase the contact area between the clamping jaw 411 and the outer peripheral surface of the incident rod 12, thereby increasing friction and ensuring a tightening effect. The arcuate piece 4111, which is slightly smaller than the radius of the incident rod 12, can further undergo slight elastic deformation when contacting the incident rod 12, thereby ensuring a contact effect and increasing the clamping force. The provision of the hinge seat 4112 allows the arcuate piece 4111 to rotate relative to the incident rod 12 within a certain angle. Since the connecting rod 412 rotates during movement, the provision of the hinge seat 4112 can ensure that the inner curved surface of the arcuate piece 4111 always faces the outer peripheral surface of the incident rod 12, ensuring that the movement is unobstructed.

[0036] As an embodiment, the two connecting rods 412 can also be arranged crosswise, and the driving device drives the transmission rod gradually away from the incident rod 12 to convert the clamping release device 40 from a released state to a clamped state. Furthermore, the connecting rod 412 can be divided into a shorter first connecting rod and a longer second connecting rod. The two connecting rods 412 intersect at the connection between the first connecting rod and the second connecting rod. The clamping claw 411 is set on the first connecting rod. Through the lever principle, a larger clamping force is generated by a smaller driving force. However, this structure will also cause the transmission rod to move a longer distance to create a gap between the clamping claw 411 and the incident rod 12, which slows down the release speed. Therefore, the setting method of the connecting rod 412 can be selected according to actual needs.

[0037] In order to further speed up the conversion speed of the clamping and releasing device 40 from the clamping state to the releasing state, as shown in FIG. Figure 2 As shown, the clamping release device 40 further includes an elastic member 44, which is disposed between the two connecting rods 412. During the transition from the release state to the clamping state, the clamping release device 40 gradually stretches the elastic member 44 and causes it to undergo elastic deformation. The elastic member 44 can be a cylindrical spring, a conical spring, a rubber rod, or other elastically deformable component. During the transition from the release state to the clamping state, the angle between the extension directions of the two connecting rods 412 gradually decreases, thereby compressing the elastic member 44 to undergo elastic deformation and accumulate elastic potential energy. When the driving device drives the clamping jaws 411 away from the incident rod 12, the elastic member 44 will also release its accumulated elastic potential energy. The connecting rod 412 will move under the combined action of the elastic member 44 and the driving assembly 43, thereby further increasing the release speed.

[0038] At this time, the driving assembly 43 drives the transmission rod to provide a thrust F, and provides a radial pressure Q on the clamping jaw 411 through the connecting rod 412. The radial pressure Q can be calculated by the following formula:

[0039] ;

[0040] Where l2 is the distance from the cylindrical pin to the shear axis when the friction plate holder is clamped; l3 is the distance from the connection point between the connecting rod 412 and the elastic member 44 to the hinge point of the connecting rod 412; α1 is the angle between the transmission rod and the connecting rod 412 in the clamped state; θ is the friction angle between the end of the transmission rod and the slide rail; F S is the working load of the elastic member 44.

[0041] In the clamping state, the tension spring is stretched and deformed to generate tension. The generated working load is required to be less than the maximum load allowed by the elastic member 44 and greater than the minimum working load required by the test, so that the clamping jaw 411 can complete the transition from the clamping state to the release state at a response speed of no more than 1ms under the joint action of the elastic member 44 and the drive assembly 43. When the spring is used as the implementation method, this working load requires that the working load generated by the elastic member 44 is F S It can be calculated by the following formula:

[0042] ;

[0043] Wherein, α0 is the angle between the transmission rod and the connecting rod 412 when the clamping release device 40 is in the released state; α1 is the angle between the transmission rod and the connecting rod 412 when the clamping state is in the clamped state; G is the shear modulus of the material of the elastic member 44; d is the material diameter; D is the spring mean diameter; and n is the effective number of coils of the spring.

[0044] In some embodiments, the drive assembly 43 includes a hydraulic cylinder having a telescopic end that can be moved toward or away from the incident rod 12, the telescopic end being connected to the transmission rod. Using a hydraulic cylinder as an implementation allows, on the one hand, the hydraulic cylinder to exert a large driving force, and on the other hand, to achieve rapid motion by quickly releasing the hydraulic oil within the hydraulic cylinder. Furthermore, when the hydraulic cylinder is adjusted to drive the transmission rod away from the incident rod 12, the flow of hydraulic oil can be further accelerated by a device such as a liquid pump, thereby creating a gap between the clamping jaw 411 and the incident rod 12 and achieving instantaneous release of torque.

[0045] In addition, if Figure 1 、 Figure 4 As shown, the support device 30 also includes a base plate, to which multiple guide supports 31 are fixed. These guide supports 31 are spaced along the length of the base plate. Specifically, both the torsion bar assembly and the loading device can be mounted on the base plate, connecting the entire device as a single unit. The multiple guide supports 31 provide sufficient support for the incident rod 12, ensuring balanced force distribution. Gravity prevents the incident rod 12 from bending, which could affect the experimental process.

[0046] As an optional embodiment, in order to facilitate the installation of the incident rod 12, as shown in FIG. Figure 1 As shown, the guide support 31 includes a lower seat body 312 and an upper seat body 311. A first groove is provided on the top of the lower seat body 312, and a second groove corresponding to the first groove is provided on the upper seat body 311. The upper seat body 311 can be fixed on the lower seat body 312 so that the first groove and the second groove are combined to form a first through hole; a radial bearing 313 is provided in the first through hole.

[0047] During installation, the radial bearing 313 can be first installed on the incident rod 12, and then installed together with the incident rod 12 into the first groove, and then the upper seat 311 is installed, eliminating the process of passing the incident rod 12 through multiple guide supports 31 in sequence, thereby simplifying the installation process of the experimental equipment and reducing the workload of the experimental preparation process.

[0048] As a specific implementation method, Figure 1 As shown, the loading device includes a thrust assembly 21 and a torsion assembly 22. The thrust assembly 21 and the torsion assembly 22 are respectively connected to the two ends of the torsion bar device. The thrust assembly 21 can push the torsion bar device in the axial direction to apply axial pressure to the test sample, and the torsion assembly 22 can twist the incident rod 12 to rotate.

[0049] In this embodiment, the torsion assembly 22 may be mainly composed of a gear rack swing hydraulic cylinder, a coupling, and a base 34. The gear rack hydraulic cylinder and the base 34 are connected together by bolts. The cylinder body of the gear rack hydraulic cylinder is welded together by two parts. A rack is machined on the piston rod, and the rack is connected to the transmission shaft as a whole. When oil enters the front chamber of the hydraulic cylinder and returns to the rear chamber, the rack moves backward to the left, and the rack drives the gear to rotate counterclockwise; otherwise, it rotates clockwise. The swing angle of the gear shaft can be selected arbitrarily and can be greater than 360°. The gear and the torsion bar are coaxially connected through a coupling. The torque loading device can output large torque, avoid vibration and other conditions, and achieve high-precision, low-noise transmission. The thrust assembly 21 can be a device that can push the fixed assembly 11 to move axially.

[0050] In some embodiments, as Figure 1 、 Figure 3 As shown, the thrust assembly 21 is connected to the fixed assembly 11, and the torsion assembly 22 is connected to the incident rod 12; the support device 30 also includes a rigid support 32 fixed to the base plate, and the rigid support 32 is arranged at one end of the incident rod 12 close to the torsion assembly 22, and the rigid support 32 and the guide support 31 are spaced apart along the extension direction of the incident rod 12; the rigid support 32 is provided with a second through hole, and a thrust bearing 321 is provided in the second through hole.

[0051] Specifically, the rigid support 32 can be divided into two left and right parts, fixed to the base 34. The bottom of the rigid support 32 is connected to the base 34 by bolts. Threaded holes are provided at the four corners of the left and right rigid supports 32. The rigid support 32 located on the side closest to the thrust assembly 21 has a second through-hole in the middle. The inner diameter of the second through-hole matches the outer diameter of the piston push rod of the thrust assembly 21, allowing only axial movement. The thrust assembly 21 can be fixed to the rigid support 32. The underside of the thrust assembly 21 can be provided with a pulley or slide structure to facilitate the movement of the thrust assembly 21 and the installation of the test sample.

[0052] A second through-hole is also located in the center of the rigid support 32, located near the torsion assembly 22. The inner diameter of this second through-hole matches the outer diameter of the incident rod 12, allowing for both rotation and axial movement. The thrust bearing 321 consists of two thrust washers and several rolling elements. The thrust washers are divided into shaft and seat plates, and the rolling elements are integrated into a single unit by an iron cage. This bearing can withstand axial loads in one direction and restrict axial movement of the incident rod 12 to that direction, ensuring stability during torsion and facilitating disassembly and assembly of the torsion bar.

[0053] Furthermore, the two rigid supports 32 can be connected by a tie rod 33. Specifically, a plurality of tie rods 33 are provided, and the two ends of the tie rods 33 are fixedly provided on the rigid supports 32 respectively. The specific connection method can be a connection method that is convenient for disassembly and installation, such as screw connection. The plurality of tie rods 33 can be symmetrically arranged in pairs. When axial loading is performed, the rigid support 32 close to the torsion assembly 22 will be subjected to a large thrust in the direction of the torsion assembly 22. By providing a plurality of tie rods 33, the device is connected as a whole to achieve internal pressure balance, ensuring that the incident rod 12 will not be compressed and unstable when axial loading is performed. That is, the thrust of the rigid support 32 at the other end can be dispersed, the supporting force can be enhanced, the stability of the entire structure can be maintained, and the incident rod 12 can be prevented from being compressed and deformed excessively and becoming unstable.

[0054] To collect experimental data, the fixture assembly 11 includes a fixture slot for mounting the test sample. The slot extends along the direction of the incident rod 12, and a measurement sensor is positioned outside the slot. The slot can be composed of a transmissive rod and a cylinder secured to its end. The incident rod 12 can extend into the slot. During the experiment, the force applied to the test material within causes it to squeeze against the sidewalls of the slot. Therefore, a strain sensor can be fixed to the outer sidewalls of the slot to capture experimental data.

[0055] The measurement sensor can be implemented using a resistance strain gauge. During the experiment, the resistance strain gauge is pasted onto the incident rod 12. The two sets of strain gauges used for axial pressure measurement and calibration are strictly adhered to the outer surface of the side wall of the fixed groove along the axial direction symmetrically in accordance with the standard to verify that the positive pressure of the friction interface is the same everywhere; then the two sets of strain gauges are symmetrically pasted at a 45° angle to the axial direction on the surface of the incident rod 12 located on the left side of the clamping position for shear stress measurement. It is required that the incident torsional wave pulse and the torsional wave pulse reflected from the friction interface do not overlap and affect the measurement. When the torsional wave acts on the strain gauge during the transmission process, it causes the strain gauge to produce a slight mechanical deformation, thereby causing the resistance value of the strain gauge to change. By converting the changed resistance signal into a voltage signal, shear stress measurement is achieved; in order to convert the resistance change of the strain gauge into a voltage signal, a bridge circuit is usually used for measurement. This embodiment uses a full-bridge measurement circuit, which helps to eliminate the influence of bending waves.

[0056] In order to conveniently determine the magnitude of the torque applied by the torsion assembly 22, as shown in FIG. Figure 4The loading device also includes a sensor assembly 23, which includes a torque sensor and a sensor bracket. The torque sensor is positioned between the incident rod 12 and the torsion assembly 22. The sensor bracket is fixed to the base plate and connected to the torque sensor. The torque sensor is a dynamic torque sensor, used to measure the magnitude of the applied torque during the experiment. It can continuously measure forward and reverse torque and rotational speed. The torque sensor is supported by bearings at both ends, and the upper shaft is coaxially connected to the torsion assembly 22 and the incident rod 12 via a coupling.

[0057] Those skilled in the art will appreciate that the above-mentioned embodiments are specific examples for implementing the present disclosure, and that in actual applications, various changes may be made thereto in form and detail without departing from the scope of the present disclosure.

Claims

1. A Hopkinson torsion bar test apparatus, characterized in that: The Hopkinson torsion bar experimental equipment includes: Torsion bar device, loading device, support device and clamping release device; The torsion bar device includes a fixing assembly and an incident rod, the test sample is clamped between the fixing assembly and the incident rod, the loading device is used to drive the torsion bar device to apply a force to the test sample, the supporting device includes a guide support, the guide support is provided with a first through hole arranged along the extension direction of the incident rod, the incident rod can pass through the first through hole, the clamping release device is provided on the guide support and can clamp the incident rod in the circumferential direction, and the loading device can drive the incident rod to rotate; The clamping and releasing device includes a clamping assembly, a transmission rod, and a driving assembly. The clamping assemblies are provided with two and are mirror-imaged on both sides of the incident rod. The clamping assembly includes a clamping claw and a connecting rod. The clamping claw is provided at the first end of the connecting rod. The middle part of the connecting rod is hinged to the guide support. The second end of the connecting rod is provided with a guide rail. Both ends of the transmission rod can slide along the guide rail, and the driving assembly can drive the connecting rod to move in the vertical direction; The clamping and releasing device includes a clamping state in which the clamping jaws are tightly clamped to the outer peripheral surface of the incident rod, and a releasing state in which a gap exists between the clamping jaws and the outer peripheral surface of the incident rod; The driving assembly can drive the connecting rod to move closer to or away from the incident rod, so that the clamping and releasing device can be switched between the clamping state and the releasing state.

2. The Hopkinson torsion bar test apparatus according to claim 1, characterized in that: The clamping claw includes an arc-shaped piece and a hinge seat provided at the first end of the connecting rod, the arc-shaped piece can be attached to the outer peripheral surface of the incident rod, the arc-shaped piece is hinged on the hinge seat and can rotate in the vertical direction; The arc radius of the inner side surface of the arc-shaped piece is less than or equal to the radius of the incident rod.

3. The Hopkinson torsion bar test apparatus according to claim 1, characterized in that: The clamping and releasing device further comprises an elastic member, which is arranged between the two connecting rods. When the clamping and releasing device is switched from the release state to the clamping state, the elastic member is gradually stretched and elastically deformed.

4. The Hopkinson torsion bar test apparatus according to claim 1, characterized in that: The driving assembly includes a hydraulic cylinder having a telescopic end that can move closer to or farther away from the incident rod, and the telescopic end is connected to the transmission rod.

5. The Hopkinson torsion bar test apparatus according to claim 1, characterized in that: The supporting device further comprises a bottom plate, and the guide supports are fixed on the bottom plate and are provided in plurality, wherein the plurality of guide supports are sequentially spaced apart along the length direction of the bottom plate.

6. The Hopkinson torsion bar test apparatus according to claim 5, characterized in that: The guide support includes a lower body and an upper body, the lower body is provided with a first groove on the top, and the upper body is provided with a second groove corresponding to the first groove, and the upper body can be fixed to the lower body so that the first groove and the second groove are combined to form the first through hole; A radial bearing is disposed in the first through hole.

7. The Hopkinson torsion bar test apparatus according to claim 5, characterized in that: The loading device includes a thrust assembly and a torsion assembly, and the thrust assembly and the torsion assembly are respectively connected to the two ends of the torsion bar device. The thrust assembly can push the torsion bar device in the axial direction to apply axial pressure to the test sample, and the torsion assembly can twist the incident rod to rotate.

8. The Hopkinson torsion bar test apparatus according to claim 7, characterized in that: The thrust assembly is connected to the fixed assembly, and the torsion assembly is connected to the incident rod; The support device further includes a rigid support fixed to the base plate, the rigid support being arranged at one end of the incident rod close to the torsion assembly, and the rigid support and the guide support being spaced apart along the extending direction of the incident rod; The rigid support is provided with a second through hole, and a thrust bearing is provided in the second through hole.

9. The Hopkinson torsion bar test apparatus according to claim 1, characterized in that: The fixing assembly includes a fixing groove for arranging a test sample, the fixing groove is arranged along the extending direction of the incident rod, and a measuring sensor is arranged on the outer side of the fixing groove.

10. The Hopkinson torsion bar test apparatus according to claim 7, characterized in that: The loading device further includes a sensor assembly, which includes a torque sensor and a sensor bracket. The torque sensor is arranged between the incident rod and the torsion assembly. The sensor bracket is fixed to the base plate and connected to the torque sensor.

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