Hopkinson torsion bar experimental equipment

Abstract

The invention relates to the technical field of experimental equipment, in particular to Hopkinson torsion bar experimental equipment which is characterized in that a clamping and releasing device is arranged on a guide support and can clamp an incident bar in the circumferential direction; the clamping and releasing device comprises clamping assemblies, a transmission rod and a driving assembly, the two clamping assemblies are arranged on the two sides of the incident rod in a mirroring mode, each clamping assembly comprises a clamping jaw and a connecting rod, the clamping jaws are arranged at the first ends of the connecting rods, the middles of the connecting rods are hinged to the guide support, and guide rails are arranged at the second ends of the connecting rods; the two ends of the transmission rod can slide along the guide rails. The driving assembly can drive the connecting rod to move in the vertical direction. The driving assembly can drive the connecting rod to be close to or away from the incident rod, so that the clamping and releasing device can be switched between a clamping state and a releasing state. Therefore, the problems that the clamping force of the clamping and releasing device cannot be accurately controlled, the repeatability is poor and the experiment cost is high in the Hopkinson torsion bar experiment process are solved.

Description

Technical Field

[0001] The 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 conditions. It is mainly composed of a torque loading device, a clamping release device, a torsion bar incident rod, a transmission rod, etc. The transmission rod can also be replaced with a rigid support for laboratory earthquake fault friction, material friction and wear research. For traditional high-speed friction devices, it can apply high-speed rotational shear force to the sample through a high-power servo motor through a gear / belt speed change system, but the device can only achieve high-speed rotation under low axial pressure. Under high axial pressure, a higher torque is required to start, which puts higher requirements on the torque loading system. The Hopkinson torsion bar is based on the principle of the Hopkinson bar, using the propagation of stress waves in the bar to simulate the stress state of the material during high-speed torsion. Scholars have begun to study it in the 1970s. After that, various loading methods such as pre-energy storage, explosion, flywheel, and electromagnetic have appeared one after another, but the most widely used one is the pre-energy storage type.

[0003] In the pre-energy storage split Hopkinson torsion bar experiment, the sample is fixed between the rotatable incident rod and the transmission rod, and the incident rod is divided into two by the clamping and releasing device. The section away from the sample is the energy storage section, and the other section is prevented from twisting by the clamping and releasing device. The basic requirement of the clamping and releasing device is that when the external torque is applied to the energy storage section, the torsion bar can be reliably clamped and released transiently. When the clamping and releasing mechanism clamps the incident rod, the energy storage section can store energy under the action of the external torque. After reaching the predetermined value of the experiment, the clamping and releasing device is suddenly released, and the stored energy of the energy storage section will quickly propagate in the rod in the form of a torsional wave, acting on the sample and generating corresponding torsional strain. By measuring and analyzing the propagation process of the stress wave and the strain response of the sample, the mechanical parameters of the material under high-speed torsion conditions, such as shear strength and shear modulus, can be obtained.

[0004] The torque loading device and the clamping release device are the core parts of the Hopkinson torsion bar. There are many types of torque loading devices for traditional Hopkinson torsion bars. There are torque loading devices mainly composed of hydraulic systems, limit plates, gear belts, gear discs and sleeves. The gear belt fixed on the support is meshed with the gear disc positioned by the sleeve on the energy storage section of the incident rod to achieve torque loading on the energy storage rod and store energy. However, it can only provide intermittent movement in one direction, and it is difficult to accurately control the angle of rotation. Direct impact loading such as explosive loading will inevitably produce bending waves by directly hitting the free end of the rod, affecting the test accuracy. There are also stepper motors used as torque loading devices. Stepper motors have the advantages of easy control, small space and low cost, but stepper motors are difficult to obtain large torque. Low-frequency oscillation will occur during low-speed rotation, resulting in long-term speed instability, and high-load operation may cause the motor to overheat, thus affecting its performance and life.

[0005] The clamping and releasing device of the traditional Hopkinson torsion bar is mainly composed of two semicircular bridge arms connected by a dumpling and a slotted bolt. The necessary clamping force is provided for the energy storage section by adjusting the tightening degree of the slotted bolt. However, in practical applications, when the accumulated energy stored in the energy storage section reaches the predetermined value of the experiment, the clamp needs to be released by cutting off the slotted bolt. This clamping and releasing device and operation method have significant shortcomings. First, in the process of applying the clamping force, the slotted bolt is often chosen to continue tightening due to insufficient clamping force, but the slotted bolt is prone to break due to over-tightening, resulting in experimental failure; or when the slotted bolt needs to be cut off to release the clamp, the timing of cutting is often difficult to accurately control, with great uncertainty, and the experimental repeatability is poor, which not only reduces the experimental efficiency, but also greatly limits the further development and wide application of the split Hopkinson torsion bar technology; on the other hand, from the perspective of experimental cost, since each torque release requires cutting off a slotted bolt, and it takes time to replace a slotted bolt after each test, this greatly increases the cost of the experiment. Summary of the invention

[0006] In order to solve the problems that the clamping force of the clamping release 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, including: a torsion bar device, a loading device, a supporting device and a 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 extending direction of the incident rod, the incident rod can pass through the first through hole, the clamping release 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 comprises 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 comprises 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 comprises a clamping state in which the clamping claw is tightly attached to the outer peripheral surface of the incident rod, and a releasing state in which there is a gap between the clamping claw and the outer peripheral surface of the incident rod; the driving assembly can drive the connecting rod to approach or move 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 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.

[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 is switched 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 bottom plate, a plurality of guide supports are fixed on the bottom plate, and the plurality of guide supports are sequentially spaced along the length direction of the bottom plate. In some embodiments, the guide support comprises a lower seat body and an upper seat body, a first groove is provided on the top of the lower seat body, a second groove corresponding to the first groove is provided on the upper seat body, and the upper seat body can be fixed on the lower seat body so 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 two ends of the torsion bar device. The thrust assembly can push the torsion bar device in an 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 supporting device also includes a rigid support fixed on 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 setting 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 includes 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] In order to solve the problems that the clamping force of the clamping release device cannot be accurately controlled, the repeatability is poor, and the experimental cost is high 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 to be clamped, so as to push the connecting rod to rotate, thereby driving the clamping claws arranged 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 more accurately controlled, 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 the experimental process can be reproduced more accurately, and the setting of the slotted bolt, a disposable component that is difficult to control accurately, is eliminated, 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 diagram of the structure of a Hopkinson torsion bar test device according to an embodiment is shown;

[0018] Figure 2 Shows 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 test device according to another embodiment is shown.

[0021] Figure markings: 11-fixed assembly; 12-incident rod; 21-thrust assembly; 22-torque assembly; 23-sensor assembly; 30-support device; 31-guide support; 311-upper seat body; 312-lower seat body; 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; 42-transmission rod; 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 thus implement the present disclosure, rather than implying any limitation on the scope of the present disclosure.

[0023] As used herein, the term "including" and its variants 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". The orientation or position relationship indicated by the terms "upper", "lower", "left", "right", "front", "back", "top", "bottom", "inner", "outer", "vertical", "horizontal", "lateral", "longitudinal" and the like is based on the orientation or position relationship shown in the accompanying drawings. These terms are mainly for better describing the present application and its embodiments, and are not used to limit the indicated devices, elements or components to have a specific orientation, or to be constructed and operated in a specific orientation. In addition, in addition to being used to indicate an orientation or position relationship, some of the above terms may also be used to indicate other meanings, such as the term "upper" may also be used to indicate a certain dependency or connection relationship in some cases. For those of ordinary skill in the art, the specific meanings of these terms in this application can be understood according to the specific circumstances. In addition, the terms "install", "set", "provided with", "connected" and "connected" should be understood in a broad sense. 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 directly connected, or indirectly connected through an intermediate medium, or it can be 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 and 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 apparatus, 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 arranged 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 arranged 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 42 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 42 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 attached to the outer peripheral surface of the incident rod 12, and a releasing 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 to approach or move away from the incident rod 12, so that the clamping release device 40 can switch between the clamping state and the releasing state.

[0025] It should be noted that in the Hopkinson torsion bar test, it is necessary to apply torsion and driving force in the axial direction to the test sample at the same time. Generally speaking, the test sample may include two sub-samples, one of which is fixed on the fixing component 11, and the other sub-sample is fixed on the incident rod 12. During the experiment, one of the sub-samples can be driven to rotate by the incident rod 12, and the torsion wave generated in the process is transmitted to the test sample through the incident rod 12, thereby generating corresponding torsional strain. Therefore, during the test, it is necessary to first fix the incident rod 12, and then apply a rotational torque to it, so that it undergoes elastic deformation and accumulates energy.

[0026] In the above technical solution, the driving assembly 43 is used to push the transmission rod 42 to approach or move 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 42 or the distance from the incident rod 12, the clamping force of the clamping assembly when clamping the incident rod 12 can be more accurately controlled, 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 the experimental process can be reproduced more accurately, and the setting of the slotted bolt, a disposable component that is difficult to accurately control, is eliminated, 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] Among them, the fixing assembly 11 may include a transmission rod, and the sub-sample may be fixed on the side of the transmission rod facing the incident rod 12. The fixing method may be appropriately selected according to the situation. Specifically, it is preferred to use AB type epoxy resin for bonding. Similarly, the sub-sample may also 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 setting of the guide support 31 is used to fix the incident rod 12 at an appropriate height on the one hand, and the installation of the connecting rod 412 provides a fixed attachment point so that it can rotate. Of course, it can be understood that the connecting rod 412 may also be attached to other separately arranged brackets to achieve the same effect, and being hinged on the guide support 31 can reduce the number of parts and simplify the equipment. The clamping claw 411 may be a relatively simple sheet-shaped, block-shaped or contoured claw with a shape similar to the outer peripheral surface of the incident rod 12, or it may be a relatively complex manipulator with components such as movable joints and a drive device, and it only needs to be able to fully clamp the incident rod 12. The connecting rod 412 is made of hard material and has high mechanical strength to resist deformation caused by the force. The connecting rod 412 can be fixed by a hinge or connected by a pin connection. For the hinged parts, since they need to fix the parts and bear the shear force, the material can be high-quality carbon steel after appropriate heat treatment. The above material has high strength, high wear resistance and high corrosion resistance, and has good comprehensive mechanical properties. The two ends of the transmission rod 42 can be provided with a slider and other structures matching the guide rail 4121, or a sliding bearing node can be used as a specific implementation method. The sliding bearing node can ensure that the transmission rod 42 can slide along the guide rail 4121, and can also reduce the friction between the guide rail 4121 during the sliding process. In addition, the transmission rod 42 will also rotate relative to the connecting rod 412 during the sliding process. The sliding bearing node can also not hinder the rotation, making the structure more flexible in force transmission. In addition, since the guide rail 4121 and the sliding bearing node are in infinitesimal line contact in theory, the sliding bearing node and the guide rail 4121 wall must be deformed to form surface contact to achieve pressure transmission, so it is necessary to ensure that the metal material used will not be plastically deformed and damaged due to extrusion and slippage, and has sufficient rigidity and strength to withstand the load and impact during operation. The drive component 43 can be a mechanical structure such as an electric motor, a pneumatic cylinder, and 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 42 and the connecting rod 412 when the clamping release device 40 is in the released state; α2 is the angle between the transmission rod 42 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 42.

[0031] At the same time, the angle α between the transmission rod 42 and the connecting rod 412 and the stroke h of the transmission rod 42 satisfy the following relationship:

[0032]

[0033] Wherein, α0 is the angle between the transmission rod 42 and the connecting rod 412 when the clamping release device 40 is in the released state; l1 is the distance between the far 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 clamp 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 side surface of the arc-shaped piece 4111 is less than or equal to the radius of the incident rod 12.

[0035] The setting of the arc piece 4111 can increase the contact area between the clamping claw 411 and the outer peripheral surface of the incident rod 12, thereby increasing the friction force and ensuring the tightening effect. The arc 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 the contact effect and improving the clamping force. The setting of the hinge seat 4112 allows the arc piece 4111 to rotate relatively within a certain angle. Since the connecting rod 412 rotates during the movement, the setting of the hinge seat 4112 can ensure that the inner arc surface of the arc piece 4111 always faces the outer peripheral surface of the incident rod 12, ensuring that the movement is not hindered.

[0036] As an implementation mode, the two connecting rods 412 can also be cross-arranged, and the driving device drives the transmission rod 42 to gradually move away from the incident rod 12 so that the clamping release device 40 is converted 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 jaw 411 is arranged 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 42 to move a longer distance to create a gap between the clamping jaw 411 and the incident rod 12, thereby slowing 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 also includes an elastic member 44, which is arranged between the two connecting rods 412. The clamping release device 40 gradually stretches the elastic member 44 and causes it to undergo elastic deformation during the process of switching from the release state to the clamping state. The elastic member 44 can be a cylindrical spring, a conical spring, a rubber rod or other elastically deformable parts. During the process of switching from the release state to the clamping state of the clamping release device 40, 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 jaw 411 away from the incident rod 12, the elastic member 44 will also release its accumulated elastic potential energy, and the connecting rod 412 will move under the joint action of the elastic member 44 and the driving assembly 43, thereby further improving the release speed.

[0038] At this time, the driving assembly 43 drives the transmission rod 42 to provide a thrust F, and provides a radial pressure Q to the clamping jaw 411 through the connecting rod 412. The radial pressure Q can be calculated by the following formula:

[0039]

[0040] Wherein, l2 is the distance from the cylindrical pin to the shear axis when the friction plate seat is clamped; l3 is the distance from the connection 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 42 and the connecting rod 412 in the clamped state; θ is the friction angle between the end of the transmission rod 42 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, and 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 driving 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 42 and the connecting rod 412 when the clamping release device 40 is in the released state; α1 is the angle between the transmission rod 42 and the connecting rod 412 when the clamping 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 driving assembly 43 includes a hydraulic cylinder, which has a telescopic end that can move closer to or farther from the incident rod 12, and the telescopic end is connected to the transmission rod 42. When the hydraulic cylinder is used as an implementation method, on the one hand, the hydraulic cylinder can exert a large driving force, and on the other hand, the hydraulic oil in the hydraulic cylinder can be quickly released to achieve the purpose of rapid action. Furthermore, when the hydraulic cylinder is adjusted to drive the transmission rod 42 away from the incident rod 12, the outflow of the hydraulic oil can be further accelerated through a liquid pump or other device, so that a gap is generated between the clamping jaw 411 and the incident rod 12 to achieve instantaneous release of torque.

[0045] In addition, if Figure 1 , Figure 4 As shown, the support device 30 also includes a base plate, and a plurality of guide supports 31 are fixed on the base plate, and the plurality of guide supports 31 are arranged in sequence and spaced along the length direction of the base plate. Specifically, both the torsion bar device and the loading device can be arranged on the base plate, so that the entire device is connected as a whole. The arrangement of the plurality of guide supports 31 can provide a relatively sufficient support for the incident rod 12. And the force is balanced, and the incident rod 12 will not bend under the action of gravity, thereby affecting the experimental process.

[0046] As an optional embodiment, in order to facilitate the installation of the incident rod 12, as Figure 1 As shown, the guide support 31 includes a lower seat body 312 and an upper seat body 311. The top of the lower seat body 312 is provided with a first groove, and the upper seat body 311 is provided with a second groove corresponding to the first groove. 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 body 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, etc. The gear rack hydraulic cylinder and the base 34 are connected together by bolts, and the cylinder body of the gear rack hydraulic cylinder is welded by two parts, and a rack is processed on the piston rod, and the rack is connected to the transmission shaft as a whole. When the front chamber of the hydraulic cylinder enters the oil and the rear chamber returns the oil, the rack moves backward to the left, and the rack drives the gear to rotate counterclockwise; otherwise, it rotates clockwise, and the swing angle of the gear shaft can be arbitrarily selected and can be greater than 360°. The gear and the torsion bar are coaxially connected through a coupling. The torque loading device can output a large torque, avoid vibration and other conditions, and realize 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, 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, 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 arranged at intervals 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 pieces on the left and right and fixed on the base 34. The bottom of the rigid support 32 is connected to the base 34 by bolts. The four corners of the two rigid supports 32 on the left and right have threaded through holes. The rigid support 32 on the side close 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, and only axial movement is allowed. The thrust assembly 21 can be fixed on the rigid support 32, and the lower side of the thrust assembly 21 can be provided with structures such as pulleys or slideways to facilitate the movement of the thrust assembly 21 and the installation of the test sample.

[0052] A second through hole is also provided in the middle of the rigid support 32 disposed near one side of the torsion assembly 22, and the inner diameter of the second through hole matches the outer diameter of the incident rod 12, allowing rotation and axial movement. The thrust bearing 321 is composed of two thrust washers and a plurality of rolling bodies, wherein the thrust washers are divided into shaft pieces and seat pieces, and the rolling bodies are combined into a whole by an iron cage, which can withstand axial loads in one direction and limit the axial movement of the incident rod 12 in only one direction, so that the sample can remain stable when twisted, and facilitate the 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 respectively fixedly provided on the rigid supports 32. The specific connection method can be a connection method such as screw connection that is convenient for disassembly and installation. The plurality of tie rods 33 can be symmetrically arranged in pairs. When axial loading is performed, the rigid supports 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 during axial loading, 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 overall structure can be maintained, and the incident rod 12 can be prevented from being compressed and deformed too much and becoming unstable.

[0054] In order to collect experimental data, the fixing assembly 11 includes a fixing groove for setting the test sample, the fixing groove is set along the extension direction of the incident rod 12, and a measuring sensor is set on the outside of the fixing groove. The fixing groove can be composed of a transmission rod and a cylinder fixed to the end of the transmission rod. The incident rod 12 can extend into the fixing groove. During the experiment, due to the force applied to the test material inside, the test material will squeeze the side wall of the fixing groove. Therefore, the sensor for measuring strain can be fixed on the outer side wall of the fixing groove to obtain experimental data.

[0055] The measuring sensor can use a resistance strain gauge as an implementation method. During the experiment, the resistance strain gauge is pasted onto the incident rod 12. The two groups of strain gauges used for axial pressure measurement and calibration are strictly in accordance with the standard and are symmetrically pasted on the outer surface of the side wall of the fixed groove along the axial direction to verify that the positive pressure of the friction interface is the same everywhere; then the two groups of strain gauges are symmetrically pasted at an angle of 45° 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 to affect the measurement. When the torsional wave acts on the strain gauge during the transmission process, it causes a slight mechanical deformation of the strain gauge, 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 torque applied by the torsion assembly 22, as shown in FIG. Figure 4The loading device shown also includes a sensor assembly 23, which includes a torque sensor and a sensor bracket. The torque sensor is arranged between the incident rod 12 and the torsion assembly 22. The sensor bracket is fixed to the bottom plate and connected to the torque sensor. The torque sensor adopts a dynamic torque sensor, which is used to measure the magnitude of the torque loaded during the experiment, and can continuously measure the forward and reverse torque and the rotation speed. The torque sensor is supported by bearings at both ends, and the upper shaft is coaxially connected with the torsion assembly 22 and the incident rod 12 through a coupling.

[0057] Those skilled in the art will appreciate that the above-mentioned embodiments are specific examples for implementing the present disclosure, and 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 test equipment includes: Torsion bar device, loading device, support device and clamping release 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 release device is arranged 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 release device comprises a clamping assembly, a transmission rod and a driving assembly, wherein two clamping assemblies are provided and are mirror-imaged on both sides of the incident rod, the clamping assembly comprises 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; Both ends of the transmission rod can slide along the guide rail, and the driving assembly can drive the connecting rod to move in a vertical direction; The clamping and releasing device comprises a clamping state in which the clamping jaws are 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 approach or move 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 equipment according to claim 1, characterized in that: The clamping jaw comprises an arc-shaped piece and a hinge seat arranged 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 sheet is less than or equal to the radius of the incident rod.

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

4. The Hopkinson torsion bar test equipment according to claim 1, characterized in that: The driving assembly comprises a hydraulic cylinder having a telescopic end which can be moved 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 equipment according to claim 1, characterized in that: The supporting device also includes a bottom plate, and the guide supports are fixed on the bottom plate and are provided in plurality, and the plurality of guide supports are arranged in sequence and at intervals 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 seat body and an upper seat body, the top of the lower seat body is provided with a first groove, the upper seat body is provided with a second groove corresponding to the first groove, and the upper seat body can be fixed on the lower seat body so that the first groove and the second groove are combined to form the first through hole; A radial bearing is arranged 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, wherein the thrust assembly and the torsion assembly are respectively connected to two ends of the torsion bar device, the thrust assembly can push the torsion bar device in an 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 comprises a rigid support fixed on the bottom 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 arranged at intervals along the extending direction of the incident rod; The rigid support is provided with a second through hole, and a thrust bearing is arranged in the second through hole.

9. The Hopkinson torsion bar test apparatus according to claim 1, characterized in that: The fixing assembly comprises a fixing groove for setting the 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 equipment according to claim 7, characterized in that: The loading device further comprises a sensor assembly, wherein the sensor assembly comprises a torque sensor and a sensor bracket, wherein the torque sensor is arranged between the incident rod and the torsion assembly, and the sensor bracket is fixed to the bottom plate and connected to the torque sensor.

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