Pulling / pressing-twisting synchronous loading device and using method thereof

Abstract

The invention discloses a pulling / pressing-twisting synchronous loading device and a using method thereof. The pulling / pressing-twisting synchronous loading device comprises two pulling / pressing-twisting components. Wherein the pulling / pressing-twisting component is composed of a spiral column, and the cross section of the spiral column is in a fan shape; the lead angle of the pulling / pressing-twisting component is larger than the self-locking angle and smaller than 70 degrees, and different lead angles correspond to different pulling / pressing-twisting load ratios. In the using process of the device, the two pulling / pressing-twisting components need to be screwed together and then placed between an incident rod and a sample. The incident bar, the pull / press-torsion synchronous loading device, the sample and the transmission bar need to be firmly connected. The tension / pressure-torsion synchronous loading device provided by the invention is simple in structure, can realize the mechanical property test of the material under the tension / pressure and torsion combined load only by modifying the existing experimental device, and has remarkable economic benefits and social benefits.

Description

Technical Field

[0001] The invention relates to the field of material mechanical property testing, and in particular to a device for realizing tension / compression-torsion synchronous loading and a method for using the device. Background Art

[0002] Materials are often in complex stress states during application, and their deformation and failure modes show behavioral characteristics that are significantly different from those under uniaxial loading; therefore, it is necessary to obtain the mechanical response of materials under combined loads through experiments; currently, quasi-static composite loading experimental technology has been well developed, but dynamic composite loading experimental technology still faces many challenges; Hopkinson bar is often used to measure the dynamic mechanical properties of materials due to its ingenious design and simple and easy testing methods; therefore, most of the current research results on dynamic composite loading are based on Hopkinson bar, but the implementation methods are different.

[0003] Some researchers have achieved compression-shear combined loading by changing the sample structure; however, although the above method has achieved compression-shear combined loading, there are limitations in the testing of experimental parameters; in addition, some people have proposed adding a crystal gasket to the front end of the sample, and then using the anisotropic properties of the crystal to convert the uniaxial load into a compression-shear combined load. However, for a given crystal and orientation, the compression-shear ratio is fixed, so different crystal materials and orientations are needed to adjust the compression-shear ratio; in summary, although compression-shear combined loading is achieved by modifying the sample using the existing Hopkinson pressure bar, it is still limited in its use for testing material constitutive parameters, that is, it is difficult to meet the requirements by simply improving the sample to achieve compression-shear combined loading.

[0004] Some researchers can also decompose the compression wave into compression wave and shear wave at the interface between the incident rod and the specimen by changing the end face where the incident rod contacts the specimen. The above method will generate bending waves inside the rod due to the lateral shear effect, and the friction coefficient between the rod and the specimen should be large enough to prevent slippage during loading.

[0005] Some researchers have proposed adding a torsional drive device to the Hopkinson bar. Since the traditional emission method has a millisecond control accuracy for the stress wave generation time, and the longitudinal wave speed is faster than the shear wave, the specimen generally undergoes compression loading first, followed by compression-shear combined loading, making it difficult to achieve synchronous loading. Therefore, the most important challenge in using the traditional Hopkinson bar for dynamic combined loading is the synchronization of loading.

[0006] Some researchers directly input stress waves into the incident rod through electromagnetic methods, and claimed that the main advantage of this technology is that it can accurately control the time when the stress wave is generated; then they proposed an electromagnetic clamping device for dynamic torsion, which uses the Lorentz force to release the torsional energy stored in the incident rod, thereby forming a torsional wave; therefore, the time when the stress wave is generated is accurately controlled according to the time difference caused by the wave speed difference, ensuring that the tensile and compressive stress waves and the torsional stress waves reach the sample at the same time, thereby solving the synchronization problem of dynamic composite loading, but the equipment is relatively complex and expensive, and it is difficult to promote and apply on a large scale. Summary of the invention

[0007] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a tension / compression-torsion synchronous loading device and a method of using the same; the tension / compression-torsion synchronous loading device has a simple structure and only needs to be modified on the existing experimental device to test the mechanical properties of the material under the combined load of tension / compression and torsion.

[0008] The technical solution of the present invention for solving the above technical problems is: the tension / compression-torsion synchronous loading device includes two tension / compression-torsion components; wherein the tension / compression-torsion components are composed of spiral columns, and the cross-section of the spiral columns is fan-shaped; the helical lead angle of the tension / compression-torsion components is greater than the self-locking angle and less than 70°, and different helical lead angles correspond to different tension / compression-torsion load ratios; the tension / compression-torsion components need to be screwed together, and the cross-section of the screwed parts is annular; the pressure-torsion synchronous loading device needs to be placed between the incident rod and the sample; the incident rod, the tension / compression-torsion synchronous loading device, the sample and the transmission rod need to be firmly connected to ensure that the tension / compression-torsion synchronous loading device decomposes the tension / compression force into tension / compression force and torsional moment, so that the sample can be simultaneously subjected to the combined loading of tension / compression and torsion.

[0009] A preferred solution of the present invention is characterized in that the number of spiral columns in the tension / compression-torsion member can be set to 2, 3, 4, 5, or 6.

[0010] A preferred embodiment of the present invention is characterized in that the material of the tension / compression-torsion member is a metal with a relatively high yield strength, such as titanium alloy, high manganese steel, stainless steel and high-strength aluminum alloy.

[0011] A preferred solution of the present invention is characterized in that a buffer layer, such as rubber, polyurethane, etc., is provided on the portion of the tension / compression-torsion components that are not screwed together.

[0012] A preferred embodiment of the present invention is characterized in that when the helix angle of the tension / compression-torsion member is 20°, 25°, 30°, 35°, 40° and 45°, the corresponding tension / compression-torsion load ratios are 1.66, 1.4, 1.2, 1.15, 1.1 and 0.95.

[0013] A preferred solution of the present invention is characterized in that the connection between the incident rod, the tension / compression-torsion synchronous loading device, the sample and the transmission rod can be made by gluing with epoxy resin or by mechanical assembly.

[0014] A preferred solution of the present invention is characterized in that the contact surface of the two tension / compression-torsion components screwed together should be as smooth as possible, and lubricating materials such as lubricating oil and graphite need to be applied to the contact surface during the experiment.

[0015] A preferred solution of the present invention is characterized in that the tension / compression-torsion synchronous loading device can also be applied to quasi-static tension / compression experiments, light gas gun experiments and drop hammer experiments.

[0016] A method for using a tension / compression-torsion synchronous loading device comprises the following steps: (1) The tension / compression-torsion member is connected to the incident rod and is firmly connected; (2) The other tension / compression-torsion member is connected to one end surface of the specimen and is firmly connected; (3) Assemble the assembled tension / compression-torsion member with another tension / compression-torsion member connected to the specimen; (4) Adjust the positions of the incident rod, tension / compression-torsion synchronous loading device, sample, and transmission rod so that their positions meet the experimental requirements; (5) Connect the other end of the sample to the transmission rod and make sure they are firmly connected; (6) Confirm that the strain dynamics data collector is in normal condition; (7) Setting the firing pressure and firing the bullet; (8) Collecting signals from strain gauges on the incident rod and the transmitted rod; (9) Process the signal curve through a computer.

[0017] The working principle of the tension / compression-torsion synchronous loading device and the use method thereof provided by the present invention is: torsion is generated by relative movement of two tension / compression-torsion components in the tension / compression-torsion synchronous loading device, and the tension / compression force transmitted by the pressure head or the clamp is simultaneously converted into tension / compression force and torsional moment, and the converted tension / compression force and torsional moment act on the sample at the same time, thereby realizing tension / compression-torsion synchronous loading of the sample.

[0018] Compared with the prior art, the present invention has the following beneficial effects: 1. The invention provides a tension / compression-torsion synchronous loading device and a method for using the same, which can decompose tension / compression into tension / compression and torsional moment at the same time, thereby achieving tension / compression-torsion composite loading on the specimen; 2. The invention provides a tension / compression-torsion synchronous loading device and a method for using the same, which can produce devices with different helical angles according to experimental needs, thereby changing the ratio of the tension / compression load to the torsion load; 3. The tension / compression-torsion synchronous loading device and the use method thereof provided by the present invention can be modified on the existing experimental device to realize tension / compression-torsion composite loading on the sample, and has significant economic and social benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of a specific implementation of the dynamic compression-torsion synchronous loading device of the present invention.

[0020] Figure 2 It is a schematic diagram of a specific implementation of the dynamic stretching-torsion synchronous loading device of the present invention. DETAILED DESCRIPTION

[0021] The present invention is further described in detail below in conjunction with embodiments and drawings, but the embodiments of the present invention are not limited thereto.

[0022] Embodiment 1: See also Figure 1 A compression-torsion synchronous loading device 4 of the present invention includes two compression-torsion components 9; wherein the compression-torsion component 9 is composed of a spiral column 8, and the cross-section of the spiral column 8 is a fan-shaped shape; the helical lead angle of the compression-torsion component 9 is greater than the self-locking angle and less than 70°, and different helical lead angles correspond to different compression-torsion load ratios; the compression-torsion components 9 need to be screwed together, and the cross-section of the mutually screwed parts is annular; the compression-torsion synchronous loading device 4 needs to be placed between the incident rod 2 and the sample 5; the incident rod 2, the compression-torsion synchronous loading device 4, the sample 5 and the transmission rod 7 need to be firmly connected to ensure that the compression-torsion synchronous loading device 4 decomposes the compressive stress into compressive stress and torsional shear stress, so that the sample 5 can be subjected to a combined load of compression and torsion at the same time.

[0023] The number of the spiral columns 8 in the compression-torsion member 9 is set to three.

[0024] The material of the compression-torsion member 9 is titanium alloy.

[0025] The buffer layer 10 disposed on the non-threaded parts of the compression-torsion members 9 is made of rubber.

[0026] The helix angle of the compression-torsion member 9 is 25°, and the corresponding compression-torsion load ratio is 1.4.

[0027] The connection between the incident rod 2, the compression-torsion synchronous loading device 4, the sample 5 and the transmission rod 7 can be bonded by epoxy resin.

[0028] The contact surfaces of the two compression-torsion members 9 screwed together should be as smooth as possible, and lubricating oil needs to be applied to the contact surfaces during the experiment.

[0029] The compression-torsion synchronous loading device 4 can also be applied to quasi-static compression experiments, light gas gun experiments and drop hammer experiments.

[0030] See also Figure 1 A method for using the compression-torsion synchronous loading device of this embodiment includes the following steps: (1) The compression-torsion member 9 is connected to the incident rod 2 and is firmly connected; (2) The other compression-torsion member 9 is connected to one end surface of the sample 5 and is firmly connected; (3) Screw the assembled compression-torsion component together with another compression-torsion component connected to the sample 5; (4) Adjust the positions of the incident rod 2, the compression-torsion synchronous loading device 4, the sample 5 and the transmission rod 7 so that their positions meet the experimental requirements; (5) Connect the other end surface of the sample 5 to the transmission rod 7 and connect them firmly; (6) Confirm that the strain dynamics data collector is in normal condition; (7) Setting the firing pressure and firing bullet 1; (8) Collecting signals from strain gauges 3 and 6 on the incident rod 2 and the transmission rod 7; (9) Process the signal curve through a computer.

[0031] Embodiment 2: See also Figure 2, a tensile-torsion synchronous loading device 4 of the present invention includes two; a tensile-torsion component 9; wherein the tensile-torsion component 9 is composed of a spiral column 8, and the cross-section of the spiral column 8 is a fan-shaped shape; the helical lead angle of the tensile-torsion component 9 is greater than the self-locking angle and less than 70°, and different helical lead angles correspond to different tensile-torsion load ratios; the tensile-torsion components 9 need to be screwed together, and the cross-section of the mutually screwed parts is annular; the tensile-torsion synchronous loading device 4 needs to be placed between the incident rod 2 and the sample 5; the incident rod 2, the tensile-torsion synchronous loading device 4, the sample 5 and the transmission rod 7 need to be firmly connected to ensure that the tensile-torsion synchronous loading device 4 decomposes the tensile stress into tensile stress and torsional shear stress, so that the sample 5 can be subjected to a combined load of tension and torsion at the same time.

[0032] The number of the spiral columns 8 in the tension-torsion member 9 is set to three.

[0033] The material of the tension-torsion member 9 is high-strength steel.

[0034] The helix angle of the tension-torsion member 9 is 30°, and the corresponding tension-torsion load ratio is 1.2.

[0035] The connection between the incident rod 2, the tensile-torsion synchronous loading device 4, the sample 5 and the transmission rod 7 can be achieved by mechanical assembly.

[0036] The contact surfaces of the two stretching-torsion components 9 screwed together should be as smooth as possible, and lubricating oil needs to be applied to the contact surfaces during the experiment.

[0037] The tensile-torsion synchronous loading device 4 can also be applied to quasi-static tensile experiments.

[0038] See also Figure 2 A method for using the tensile-torsion synchronous loading device of this embodiment includes the following steps: (1) The tension-torsion member 9 is connected to the incident rod 2 and is firmly connected; (2) The other stretching-torsion member 9 is connected to one end surface of the sample 5 and is firmly connected; (3) Screw the assembled stretch-torsion component together with another stretch-torsion component connected to the sample 5; (4) Adjust the positions of the incident rod 2, the tensile-torsion synchronous loading device 4, the sample 5 and the transmission rod 7 so that their positions meet the experimental requirements; (5) Connect the other end surface of the sample 5 to the transmission rod 7 and connect them firmly; (6) Confirm that the strain dynamics data collector is in normal condition; (7) Setting the launch pressure and launching the circular bullet 1; (8) Collecting signals from strain gauges 3 and 6 on the incident rod 2 and the transmission rod 7; (9) Process the signal curve through a computer.

[0039] See also Figure 1 and Figure 2 The following is a further description of the working principle of a tension / compression-torsion synchronous loading device and its use method of the present invention in conjunction with the accompanying drawings: The two tension / compression-torsion components 9 in the tension / compression-torsion synchronous loading device 4 of the present invention move relative to each other to generate torsion, thereby converting the tension / compression stress transmitted from the incident rod 2 into tension / compression stress and torsional shear stress at the same time, and the converted tension / compression stress and torsional shear stress act on the sample 5 at the same time, thereby realizing tension / compression-torsion synchronous loading of the sample 5.

[0040] The above is a preferred embodiment of the present invention, but the embodiment of the present invention is not limited to the above content. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A device for realizing tension / compression-torsion synchronous loading, characterized in that: The device includes two tension / compression-torsion components. The tension / compression-torsion components are composed of spiral columns, and the cross section of the spiral columns is fan-shaped; the spiral lead angle of the tension / compression-torsion components is greater than the self-locking angle and less than 70°, and different spiral lead angles correspond to different tension / compression-torsion load ratios; the tension / compression-torsion components need to be screwed together, and the cross section of the screwed parts is annular; the tension / compression-torsion synchronous loading device needs to be placed between the incident rod and the sample; the incident rod, the tension / compression-torsion synchronous loading device, the sample and the transmission rod need to be firmly connected.

2. A tension / compression-torsion synchronous loading device according to claim 1, characterized in that: The number of spiral columns in the tension / compression-torsion member can be set to 2, 3, 4, 5, or 6.

3. The device for realizing tension / compression-torsion synchronous loading according to claim 1, characterized in that: The material of the tension / compression-torsion component is a metal with relatively high yield strength.

4. The device for realizing tension / compression-torsion synchronous loading according to claim 1, characterized in that: The portions of the tension / compression-torsion members that are not screwed together are provided with a buffer layer.

5. The device for realizing synchronous tension / compression-torsion loading according to claim 1, characterized in that: When the helix angle of the tension / compression-torsion component is 20°, 25°, 30°, 35°, 40° and 45°, the corresponding tension / compression-torsion load ratios are 1.66, 1.4, 1.2, 1.15, 1.1 and 0.

95.

6. The device for realizing tension / compression-torsion synchronous loading according to claim 1, characterized in that: The connection between the incident rod, the tension / compression-torsion synchronous loading device, the sample and the transmission rod can be made by gluing with epoxy resin or by mechanical assembly.

7. The device for realizing synchronous tension / compression-torsion loading according to claim 1, characterized in that: The contact surface of the two tension / compression-torsion components screwed together should be as smooth as possible, and lubricating material needs to be applied to the contact surface during the experiment.

8. The device for realizing synchronous tension / compression-torsion loading according to claim 1, characterized in that: The tension / compression-torsion synchronous loading device can also be applied to quasi-static tension / compression experiments, light gas gun experiments and drop hammer experiments.

9. A method for using a tension / compression-torsion synchronous loading device according to claim 1, comprising the following steps: (1) The tension / compression-torsion member is connected to the incident rod and is firmly connected; (2) The other tension / compression-torsion member is connected to one end surface of the specimen and is firmly connected; (3) Screw the assembled tension / compression-torsion component together with another tension / compression-torsion component connected to the specimen; (4) Adjust the positions of the incident rod, tension / compression-torsion synchronous loading device, sample, and transmission rod so that their positions meet the experimental requirements; (5) Connect the other end of the sample to the transmission rod and make sure they are firmly connected; (6) Confirm that the strain dynamics data collector is in normal condition; (7) Setting the firing pressure and firing the bullet; (8) Collecting signals from strain gauges on the incident rod and the transmitted rod; (9) Process the signal curve through a computer.

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