A split Hopkinson tie rod device and method for achieving single-pulse loading

Abstract

This invention provides a split Hopkinson bar device for achieving single-pulse loading, comprising an incident bar, a transmission bar, an incident wave-catching unit, and a stress wave generating unit. The incident wave-catching unit includes an incident wave-catching sleeve and an absorbing bar. One end of the absorbing bar is spaced apart from the incident bar flange, and the other end is connected to the absorbing bar flange. The incident wave-catching sleeve is fitted around the absorbing bar, with its two ends respectively fitting against the absorbing bar flange and the incident bar flange. The compressive stress wave generated by the stress wave generating unit is reflected by the incident bar flange to form a tensile stress wave. After loading the sample, a portion of the stress wave is reflected back as a compressive wave and absorbed by the incident wave-catching unit. This solves the problem of multiple reflections and interference in traditional Hopkinson bars, achieving pure single-pulse tensile loading. The device is compact, has high energy utilization, and is suitable for testing the dynamic mechanical properties of materials.

Description

Technical Field

[0001] This invention relates to the field of dynamic mechanical property testing technology for materials, and in particular to a split Hopkinson tie rod device and method for realizing single-pulse loading. Background Technology

[0002] In the field of high-strain-rate dynamic tensile mechanical property testing of materials, the split Hopkinson bar (SHTB) technique is a core method for studying the dynamic response of materials. Traditional SHTB devices generate tensile stress waves by impacting an incident bar with a bullet. These waves reflect multiple times between the incident and transmission bars, creating a multi-pulse loading effect that significantly impacts the accuracy of experimental data. For example, while some literature mentions Hopkinson bar fatigue testing devices that can achieve high-frequency loading, they rely on a pneumatic system to recover the bullet and suppress reflected waves. Insufficient absorption efficiency leads to incomplete dissipation of residual wave energy, causing secondary or even multiple loading of the specimen, resulting in serious deviations in data accuracy. In studying strain-induced martensite formation at high strain rates, the multi-pulse loading phenomenon not only affects the precise control of material strain but also makes it difficult to establish a correlation between specimen strain and strain-induced phase transformation content, hindering research on differences in phase transformation content at different strain rates.

[0003] To address the aforementioned multi-pulse loading effect problem, most current technologies in this field employ single-momentum-trap or dual-momentum-trap separated rod devices, such as the single-momentum-trap separated rod device used in the invention patent (Invention title: Single-pulse separated Hopkinson rod experimental device based on electromagnetic force loading, authorized announcement number: CN113607545B). However, this dynamic passive bonding mode of the absorption rod cannot guarantee complete absorption of the reflected wave in the incident rod, and in practical applications, it generally faces the problem of interference from multiple pulse loading.

[0004] Existing solutions also include limiting specimen deformation by designing rigid fixtures of specific dimensions. Although this does not address the issue of improving the device, it still achieves the goal of strain control for the specimen. However, this method cannot accurately obtain the stress-strain curve of the specimen itself due to fixture interference, and it also limits the use of external digital image-related technology equipment such as high-speed cameras or infrared cameras.

[0005] In summary, existing improved technologies still have shortcomings in terms of residual multi-pulse amplitude, precise control and effective recovery of sample strain, and material compatibility. There is an urgent need for an innovative method that can achieve single-pulse loading on the split Hopkinson tie rod device. Summary of the Invention

[0006] In view of the shortcomings of the prior art described above, the present invention provides a split Hopkinson lever device for realizing single-pulse loading.

[0007] A split Hopkinson lever device for realizing single-pulse loading, characterized in that it comprises: an incident lever, an incident wave-catching unit, and a stress wave generating unit;

[0008] One end of the incident rod is connected to the incident rod flange, and the other end is used to hold the sample.

[0009] The incident wave-catching unit includes an incident wave-catching sleeve and an absorbing rod. One end of the absorbing rod is positioned opposite the incident rod flange at a certain interval, and the other end is connected to the absorbing rod flange. The incident wave-catching sleeve is sleeved outside the absorbing rod, and its two ends are respectively attached to the absorbing rod flange and the incident rod flange.

[0010] The stress wave generating unit is configured on the incident rod near the flange end of the incident rod to generate a compressive stress wave.

[0011] The compressive stress wave propagates along the incident rod flange and forms two stress waves after reaching the flange end. One of them is a compressive stress wave that, after being reflected at the incident rod flange end, forms a tensile stress wave that propagates along the incident rod and loads the sample. The other is a compressive stress wave that, after reaching the incident rod flange end, is transmitted to the incident wave trapping sleeve and propagates along the sleeve.

[0012] Among them, the compressive stress wave transmitted along the incident wave-catching sleeve reaches the absorber flange and is transmitted along the flange. After reaching the end of the flange, it is reflected to form a tensile stress wave that is transmitted along the absorber. This tensile stress wave causes the absorber flange and the absorber to separate from the incident wave-catching sleeve, blocking the transmission of subsequent stress waves.

[0013] When the tensile stress wave transmitted along the incident rod reaches the connection point between the incident rod and the specimen, due to the interface change, part of the tensile stress wave reaches the interface to form a reflected compression wave that returns to the incident rod, while part of the tensile stress wave is transmitted along the specimen, loading the specimen. The reflected compression wave is transmitted in the opposite direction along the incident rod to the flange end of the incident rod, and then transmitted through transmission to the incident wave trapping sleeve. It is reflected by the free end of the incident wave trapping sleeve to form a tensile stress wave. Due to the action of the tensile stress wave, the incident wave trapping sleeve is disengaged from the flange of the incident rod, blocking the transmission of subsequent stress waves to the incident rod, so that the specimen is only subjected to a tensile wave once, thereby performing a single pulse loading on the specimen.

[0014] Furthermore, it also includes a transmission rod and a transmission wave-catching unit coaxially arranged with the incident rod. One end of the transmission rod is connected to the transmission rod flange, and the other end clamps the sample between the transmission rod and the incident rod. The transmission wave-catching unit is a transmission wave-catching sleeve sleeved on the outside of the end of the transmission rod and fitted to the transmission rod flange. The transmitted wave is transmitted along the transmission rod and the reflected compression wave formed by the reflection of the transmission rod flange is absorbed by the transmission wave-catching sleeve, avoiding the compression of the sample by the transmission rod, thereby applying a single pulse loading to the sample.

[0015] Furthermore, the stress wave generating unit includes an impact tube coaxially sleeved on the outside of the incident rod, the impact tube being configured to generate a compressive stress wave by impacting the flange of the incident rod.

[0016] Furthermore, an incident rod strain gauge is provided at the axial middle position of the incident rod, and a transmission rod strain gauge is provided near the end of the transmission rod close to the sample.

[0017] Furthermore, the incident rod strain gauge is a resistance strain gauge, and the transmission rod strain gauge is a semiconductor strain gauge.

[0018] Furthermore, the incident wave-catching sleeve, absorbing rod, absorbing rod flange, incident rod, incident rod flange, impact tube, and transmission rod have the same density and elastic modulus.

[0019] Furthermore, the sample loading ends of the incident rod and the transmission rod are respectively provided with threaded holes or radial through grooves. The threaded holes are used to form a detachable fixed connection with the threaded end of the cylindrical sample. The radial through grooves divide the end of the rod into a first clamping part and a second clamping part. Coaxial round holes and threaded holes are provided on the first clamping part and the second clamping part to form screw mounting holes. After the two ends of the slat sample are respectively inserted into the radial through grooves of the rod, they are locked by variable cross-section connecting screws. The friction and mechanical engagement between the rod and the slat sample are enhanced by the contraction of the through grooves and the squeezing effect of the variable cross-section part, effectively suppressing relative slippage.

[0020] The present invention also provides a loading method for deploying the split Hopkinson tie rod device based on the above-mentioned single-pulse loading.

[0021] A single-pulse loading method includes the following steps:

[0022] S1. Connect to the strain measurement system via the incident rod strain gauge and the transmission rod strain gauge;

[0023] S2. The sample is coaxially connected between the incident rod and the transmission rod;

[0024] S3. The driving impact tube impacts the incident rod flange to generate a compressive stress wave;

[0025] S4. Single-pulse loading is achieved by absorbing the reflected compression wave on the incident rod through the incident wave-catching unit.

[0026] Furthermore, the strain measurement system adopts a Wheatstone bridge structure, with the incident rod strain gauge and the transmission rod strain gauge respectively connected to the Wheatstone bridge box, and then the output port of the Wheatstone bridge box is sequentially connected to the strain amplifier, the digital oscilloscope and the computer.

[0027] The beneficial effects of this invention are as follows:

[0028] (1) Through the synergistic effect of the incident wave-catching unit and the transmission wave-catching sleeve, efficient absorption of reflected compression waves is achieved, ensuring that the sample is subjected to only one tensile pulse loading, thus improving the reliability of experimental data:

[0029] Among them, the incident wave capture unit, through the spacing design between the absorbing rod and the incident rod flange and the multiple reflections between the absorbing rod and the incident wave capture sleeve, makes the absorbing rod flange and the absorbing rod first separate from the contact with the incident wave capture sleeve, and then the incident wave capture sleeve separates from the contact with the incident rod flange, thus blocking the transmission of subsequent stress waves to the incident rod.

[0030] The reflected compression wave formed by the transmission wave reflected by the transmission rod flange is absorbed by the transmission wave trapping sleeve, thereby subjecting the sample to a single pulse loading.

[0031] (2) The loading ends of the incident rod and the transmission rod are respectively provided with threaded holes or straight grooves. The threaded holes are used to form a detachable fixed connection with the threaded end of the cylindrical specimen, and the straight grooves are used to form an anti-slip fit with the protrusion of the strip-type specimen, so as to realize the rapid installation of the specimen and ensure that there is no slippage between the specimen and the rod, and only the axial degree of freedom is retained to avoid eccentric loading. It is suitable for dynamic tensile testing of various dumbbell-shaped specimens such as metals and composite materials.

[0032] (3) The existing dynamic passive bonding mode of the absorber rod must strictly control the initial gap between the absorber rod and the incident rod. This is the key factor for the success of the test. Otherwise, the absorption of the reflected compression wave in the incident rod cannot be guaranteed, which can easily lead to secondary loading. The technical solution of the present invention avoids this technical defect. It only requires bonding the two ends of the incident wave trap sleeve to the flange of the absorber rod and the flange of the incident rod, respectively. Moreover, compared with the dual momentum trap technology, this technology achieves the same effect while saving the space occupied by the overall device. Attached Figure Description

[0033] Figure 1 Yes: A schematic diagram of a split Hopkinson tie rod device for implementing single-pulse loading according to an embodiment of the present invention;

[0034] Figure 2 Yes: A typical stress wave waveform obtained by a resistance strain gauge on the incident rod according to an embodiment of the present invention.

[0035] Component names: 1 Absorbing rod flange, 2 Incident wave-catching sleeve, 3 Absorbing rod, 4 Incident rod flange, 5 Impact tube, 6 Computer, 7 Digital oscilloscope, 8 Strain amplifier, 9 Incident rod strain gauge, 10 Incident rod, 11 Sample, 12 Transmission rod strain gauge, 13 Transmission rod, 14 Transmission wave-catching sleeve, 15 Transmission rod flange. Detailed Implementation

[0036] In this invention, unless otherwise explicitly specified and limited, the terms "installation" and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0037] The technical solutions provided by the various embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0038] This invention provides a split Hopkinson tie rod device for achieving single-pulse loading, comprising at least: an incident wave-catching unit, an incident rod flange 4, an incident rod 10, a transmission rod 13, a transmission rod flange 15, a transmission wave-catching sleeve 14, and a stress wave generating unit. The incident rod flange 4, incident rod 10, transmission rod 13, and transmission rod flange 15 are arranged coaxially in sequence. A sample 11 is clamped between the incident rod 10 and the transmission rod 13. Threaded holes are respectively provided at the sample loading ends of the incident rod 10 and the transmission rod 13, and these threaded holes are used to form a detachable and fixed connection with the threaded end of a cylindrical sample. In another embodiment, radial through grooves are respectively formed at the sample loading ends of the incident rod 10 and the transmission rod 13. The radial through grooves divide the ends of the rods into a first clamping part and a second clamping part. Coaxial circular holes and threaded holes are provided on the first clamping part and the second clamping part to form screw mounting holes. After the two ends of the slat sample are respectively inserted into the radial through grooves of the rods, they are locked by variable cross-section connecting screws. The friction and mechanical engagement between the rod and the slat sample are enhanced by the contraction of the through grooves and the squeezing effect of the variable cross-section part, which effectively suppresses relative slippage. See the invention patent "A method to overcome the relative slippage between the slat sample and the rod in the Hopkinson tension bar test, application number 201410495098.2".

[0039] The incident wave-catching unit includes an incident wave-catching sleeve 2 and an absorbing rod 3. One end of the absorbing rod 3 is positioned opposite the incident rod flange 4 at a certain interval, and the other end is connected to the absorbing rod flange 1. The incident wave-catching sleeve 2 is sleeved on the outside of the absorbing rod 3, and its two ends are respectively fitted to the absorbing rod flange 1 and the incident rod flange 4. The incident wave-catching sleeve 2 and the absorbing rod 3 are configured with a clearance fit.

[0040] The transmission capture sleeve 14 is configured as a metal annular tube that is sleeved on the end of the transmission rod 13 and fits against the transmission rod flange 15.

[0041] The stress wave generating unit is configured on the incident rod 10 near one end of the incident rod flange 4 to generate a compressive stress wave. It includes an impact tube 5 coaxially sleeved on the outside of the incident rod 10. The impact tube 5 is configured to generate a compressive stress wave by sliding on the incident rod 10 at a certain speed and impacting the incident rod flange 4.

[0042] An incident rod strain gauge 9 is provided at the axial center of the incident rod 10. The incident rod strain gauge 9 is a resistance strain gauge used to measure the tensile wave and reflected compression wave signals on the incident rod 10. A transmission rod strain gauge 12 is provided at one end of the transmission rod 13 near the sample 11. The transmission rod strain gauge 12 is a semiconductor strain gauge used for high-sensitivity detection of transmitted wave signals.

[0043] The incident wave-catching sleeve 2, absorbing rod 3, absorbing rod flange 1, incident rod 10, incident rod flange 4, impact tube 5, and transmission rod 13 have the same density and elastic modulus.

[0044] The total length of the incident rod 10 is more than twice the length of the impact tube 5.

[0045] When conducting a single-pulse loading experiment using the above-mentioned single-pulse loading device, the following steps are included:

[0046] Install the equipment in S1, attach the strain gauge 9 of the incident rod and the strain gauge 12 of the transmission rod to the corresponding positions of the incident rod 10 and the transmission rod 13 respectively, connect the strain gauge 9 of the incident rod and the strain gauge 12 of the transmission rod to the Wheatstone bridge box respectively, and then connect the output port of the Wheatstone bridge box to the strain amplifier 8, the digital oscilloscope 7 and the computer 6 in sequence through BNC wire.

[0047] Specifically, strain gauge 9 is glued to the axial center of incident rod 10, wires are soldered to its leads, and connected to the two opposite arms of a Wheatstone half-bridge. Fixed resistors are connected to the other two arms of the Wheatstone half-bridge. Strain gauge 12 is glued to the transmission rod 13 near the slotted section, wires are soldered to its leads, and connected to the two opposite arms of a Wheatstone half-bridge. Fixed resistors are connected to the other two arms of the Wheatstone half-bridge. The output ports of the Wheatstone bridge box are then electrically connected to strain amplifier 8, digital oscilloscope 7, and computer 6 via BNC wires. Strain gauges 9 and 12 convert the strain change in the rod into a change in their own resistance, the signal is input to the two arms of the Wheatstone half-bridge, and finally output as a voltage change.

[0048] S2 is coaxially connected to the sample 11 between the incident rod 10 and the transmission rod 14.

[0049] Specifically, the dumbbell-shaped metal sample 11 is connected to the slot of the incident rod 10 and the transmission rod 13 by a variable cross-section bolt, so that the incident rod 10 and the transmission rod 14 retain only the translational degree of freedom in the axial direction.

[0050] S3 drives the impact tube 5 to slide on the incident rod 10 at a certain speed, impacting the incident rod flange 4 and generating a compressive stress wave.

[0051] The S4 compressive stress wave propagates along the incident rod flange 4 and forms two stress waves after reaching the flange end. One of them is a compressive stress wave that reaches the incident rod flange 4 end and is reflected to form a tensile stress wave that is transmitted along the incident rod 10 and loads the sample 11. The other is a compressive stress wave that reaches the incident rod flange 4 end and is transmitted through transmission to the incident wave trapping sleeve 2 and is transmitted along the sleeve.

[0052] Among them, the compressive stress wave transmitted along the incident wave-catching sleeve 2 reaches the absorber flange 1 and is transmitted along the flange. After reaching the end of the absorber flange 1, it is reflected to form a tensile stress wave that is transmitted along the absorber 3. The tensile stress wave causes the absorber flange 1 and the absorber 3 to separate from the incident wave-catching sleeve 2, blocking the transmission of subsequent stress waves.

[0053] When the tensile stress wave transmitted along the incident rod 10 reaches the connection point between the incident rod 10 and the sample 11, due to the interface change, part of the tensile stress wave reaches the interface to form a reflected compression wave that returns to the incident rod 10, while part of the tensile stress wave is transmitted along the sample 11. After loading the sample 11, it forms a transmitted wave that is transmitted along the transmission rod 13. The reflected compression wave is transmitted in the opposite direction along the incident rod 10 to the incident wave trapping sleeve 2, and is reflected by the free end of the incident wave trapping sleeve 2 to form a tensile wave. Due to the effect of the tensile wave, the incident wave trapping sleeve 2 is disengaged from the incident rod flange 4, blocking the transmission of subsequent stress waves to the incident rod 10, so that the sample 11 is only subjected to a tensile wave once, thus performing a single pulse loading on the sample 11. The reflected compression wave formed by the transmitted wave transmitted along the transmission rod 13 and reflected by the transmission rod flange 15 is absorbed by the transmission wave trapping sleeve 14, preventing the transmission rod 13 from squeezing the sample 11, thus performing a single pulse loading on the sample 11.

[0054] The technical features of this invention not described can be implemented by or using existing technology, and will not be repeated here. Of course, the above description is not a limitation of this invention, and this invention is not limited to the examples above. Any changes, modifications, additions or substitutions made by those skilled in the art within the scope of this invention should also be within the protection scope of this invention.

Claims

1. A split Hopkinson tie rod device for achieving single-pulse loading, characterized in that, Includes an incident rod, an incident wave-catching unit, and a stress wave generating unit; One end of the incident rod is connected to the incident rod flange, and the other end is used to load the sample; The incident wave-catching unit includes an incident wave-catching sleeve and an absorbing rod. One end of the absorbing rod is positioned opposite the incident rod flange at a certain interval, and the other end is connected to the absorbing rod flange. The incident wave-catching sleeve is sleeved outside the absorbing rod, and its two ends are respectively attached to the absorbing rod flange and the incident rod flange. The stress wave generating unit is configured on the incident rod near the flange end of the incident rod to generate a compressive stress wave. The compressive stress wave propagates along the incident rod flange and forms two stress waves after reaching the flange end. One of them is a compressive stress wave that, after being reflected at the incident rod flange end, forms a tensile stress wave that propagates along the incident rod and loads the sample. The other is a compressive stress wave that, after reaching the incident rod flange end, is transmitted to the incident wave trapping sleeve and propagates along the sleeve. Among them, the compressive stress wave transmitted along the incident wave-catching sleeve reaches the absorber flange and is transmitted along the flange. After reaching the end of the flange, it is reflected to form a tensile stress wave that is transmitted along the absorber. This tensile stress wave causes the absorber flange and the absorber to separate from the incident wave-catching sleeve, blocking the transmission of subsequent stress waves. When the tensile stress wave transmitted along the incident rod reaches the connection point between the incident rod and the specimen, due to the interface change, part of the tensile stress wave reaches the interface to form a reflected compression wave that returns to the incident rod, while part of the tensile stress wave is transmitted along the specimen, loading the specimen. The reflected compression wave is transmitted in the opposite direction along the incident rod to the flange end of the incident rod, and then transmitted through transmission to the incident wave trapping sleeve. It is reflected by the free end of the incident wave trapping sleeve to form a tensile stress wave. Due to the action of this tensile stress wave, the incident wave trapping sleeve is disengaged from the flange of the incident rod, blocking the transmission of subsequent stress waves to the incident rod, so that the specimen is only subjected to a tensile wave once, thereby performing a single pulse loading on the specimen.

2. The split Hopkinson lever device for realizing single-pulse loading according to claim 1, characterized in that: It also includes a transmission rod and a transmission wave-catching unit coaxially arranged with the incident rod. One end of the transmission rod is connected to the transmission rod flange, and the other end is loaded with a sample between it and the incident rod. The transmission wave-catching unit is a transmission wave-catching sleeve sleeved on the outside of the end of the transmission rod and fitted to the transmission rod flange. After the tensile stress wave loads the sample, it forms a transmission wave that is transmitted along the transmission rod. The reflected compression wave formed by the transmission rod flange is absorbed by the transmission wave-catching sleeve, thus preventing the transmission rod from squeezing the sample.

3. The split Hopkinson lever device for realizing single-pulse loading according to claim 2, characterized in that: The stress wave generating unit includes an impact tube coaxially sleeved on the outside of the incident rod, the impact tube being configured to generate a compressive stress wave by impacting the flange of the incident rod.

4. A split Hopkinson lever device for realizing single-pulse loading according to claim 2 or 3, characterized in that: An incident rod strain gauge is provided at the axial middle position of the incident rod, and a transmission rod strain gauge is provided near the end of the transmission rod close to the sample.

5. A split Hopkinson lever device for realizing single-pulse loading according to claim 4, characterized in that: The incident rod strain gauge is a resistance strain gauge, and the transmission rod strain gauge is a semiconductor strain gauge.

6. A split Hopkinson lever device for realizing single-pulse loading according to claim 2, characterized in that: The sample loading ends of the incident rod and the transmission rod are respectively provided with threaded holes or radial through grooves. The threaded holes are used to form a detachable fixed connection with the threaded end of the cylindrical sample. The radial through grooves divide the end of the rod into a first clamping part and a second clamping part. Coaxial round holes and threaded holes are provided on the first clamping part and the second clamping part to form screw mounting holes. After the two ends of the slat sample are respectively inserted into the radial through grooves of the rod, they are locked by variable cross-section connecting screws. The friction and mechanical engagement between the rod and the slat sample are enhanced by the contraction of the through grooves and the squeezing effect of the variable cross-section part, which effectively suppresses relative slippage.

7. A split Hopkinson lever device for realizing single-pulse loading according to claim 3, characterized in that: The incident wave-catching sleeve, absorbing rod, absorbing rod flange, incident rod, incident rod flange, impact tube, and transmission rod have the same density and elastic modulus.

8. A single-pulse loading method, characterized in that, The method of using the pull rod device according to claim 1 includes the following steps: S1. Connect to the strain measurement system via the incident rod strain gauge and the transmission rod strain gauge; S2. The sample is coaxially connected between the incident rod and the transmission rod; S3. The driving impact tube impacts the incident rod flange to generate a compressive stress wave; S4. Single-pulse loading is achieved by absorbing the reflected compression wave on the incident rod through the incident wave-catching unit; The implementation of the single-pulse loading includes: The compressive stress wave propagates along the incident rod flange and forms two stress waves after reaching the flange end. One of them is a compressive stress wave that, after being reflected at the flange end, forms a tensile stress wave that propagates along the incident rod and loads the sample. The other is a compressive stress wave that, after reaching the flange end, is transmitted to the incident wave trapping sleeve and propagates along the sleeve. Among them, the compressive stress wave transmitted along the incident wave-catching sleeve reaches the absorber flange and is transmitted along the flange. After reaching the end of the flange, it is reflected to form a tensile stress wave that is transmitted along the absorber. This tensile stress wave causes the absorber flange and the absorber to separate from the incident wave-catching sleeve, blocking the transmission of subsequent stress waves. When the tensile stress wave transmitted along the incident rod reaches the connection point between the incident rod and the specimen, due to the interface change, part of the tensile stress wave reaches the interface to form a reflected compression wave that returns to the incident rod, while part of the tensile stress wave is transmitted along the specimen, loading the specimen. The reflected compression wave is transmitted in the opposite direction along the incident rod to the flange end of the incident rod, and then transmitted through transmission to the incident wave trapping sleeve. It is reflected by the free end of the incident wave trapping sleeve to form a tensile stress wave. Due to the action of this tensile stress wave, the incident wave trapping sleeve is disengaged from the flange of the incident rod, blocking the transmission of subsequent stress waves to the incident rod, so that the specimen is only subjected to a tensile wave once, thereby performing a single pulse loading on the specimen.

9. The loading method according to claim 8, characterized in that: The strain measurement system adopts a Wheatstone bridge structure, with the incident rod strain gauge and the transmission rod strain gauge connected to the Wheatstone bridge box respectively. Then, the output port of the Wheatstone bridge box is connected to the strain amplifier, digital oscilloscope and computer in sequence.

Images