Medium strain rate impact tensile test device and method for filamentous material

Abstract

The invention provides a medium-strain-rate impact tensile test device and method for filamentary materials, and belongs to the technical field of dynamic mechanical property testing of materials, the medium-strain-rate impact tensile test device comprises a rigid base support, a pneumatic impact loading system and a displacement fine-tuning system are mounted on the rigid base support, the pneumatic impact loading system is located below the displacement fine-tuning system, and the displacement fine-tuning system is located below the rigid base support. An impact buffering protection structure is arranged below the pneumatic impact loading system, the lower portion of the displacement fine adjustment system is connected with a load measuring unit, and a sample piece is installed between the load measuring unit and the pneumatic impact loading system. The pneumatic impact loading system comprises a movable loading end and an air cylinder, two parallel connecting rods are installed below the movable loading end, a piston rod of the air cylinder is vertically downwards connected with an impact head, and the impact head is movably installed on the connecting rods. According to the invention, precise centering and pre-tightening of the filiform sample are reliably tested, and impact residual energy is effectively absorbed to protect equipment, so that accurate dynamic stress-strain data of a material are obtained.

Description

Technical Field

[0001] This invention belongs to the field of dynamic mechanical property testing technology for materials, specifically relating to a device and method for medium strain rate impact tensile testing of filamentous materials. Background Technology

[0002] The dynamic mechanical properties of materials, especially at medium strain rates (typically 10). -1 Up to 10 1 s -1 The tensile response within the specified range (within a certain range) is crucial for evaluating its reliability under impact loads. For filamentous materials such as fine wires and fibers, existing testing methods have significant limitations: traditional electronic universal testing machines have low loading rates (strain rates are typically within 10). -5 Up to 10 -2 s -1 ), unable to simulate dynamic working conditions; while the split Hopkinson bar (SHPB) technology is suitable for high strain rates (10), 2 Up to 10 4 s -1 However, its system is complex, and it is extremely difficult to clamp, center and extract signals from filamentous samples, resulting in high costs and low success rates.

[0003] In addition, existing devices generally lack precise fine-tuning functions for mounting thin wire samples, and the rigid collision of moving parts after high-speed impact can easily damage the equipment. Summary of the Invention

[0004] The purpose of this invention is to provide a device and method for medium strain rate impact tensile testing of filamentous materials, which solves the problems existing in the background art.

[0005] The objective of this invention is achieved through the following technical solution:

[0006] A medium strain rate impact tensile testing device for filamentous materials, characterized in that it comprises: a rigid base support, on which a pneumatic impact loading system and a displacement fine-tuning system are mounted, the pneumatic impact loading system being located below the displacement fine-tuning system, an impact buffer protection structure being located below the pneumatic impact loading system, a load measuring unit being connected below the displacement fine-tuning system, and a specimen being installed between the load measuring unit and the pneumatic impact loading system;

[0007] The pneumatic impact loading system includes a movable loading end and a cylinder. Two parallel connecting rods are installed below the movable loading end. The piston rod of the cylinder is vertically downward and connected to the impact head. The impact head is movably mounted on the connecting rods.

[0008] Furthermore, the rigid base support includes a top beam and a base. A column is installed between the top beam and the base. A sliding platform is slidably fitted on the column. A fixed support and a reinforcing seat are sequentially fixedly installed on the column below the sliding platform. Multiple reinforcing columns are installed between the support and the base, and the reinforcing columns pass through the reinforcing seats.

[0009] Furthermore, the displacement fine-tuning system includes a lead screw, which is vertically mounted between the top crossbeam and the sliding platform via a bearing. A hand crank is mounted on the top of the lead screw, and the sliding platform at the bottom of the lead screw is engaged by a threaded pair.

[0010] Furthermore, a laser displacement sensor is installed on the column, the laser displacement sensor is located on one side of the sample, and the emitting head of the laser displacement sensor is horizontally aligned with the reflector on the side of the moving loading end.

[0011] Furthermore, the buffer protection module is mounted on the base directly below the impact head.

[0012] Furthermore, the buffer protection structure uses a buffer block made of high-performance polyurethane material.

[0013] Furthermore, sample clamps are installed below the load measuring unit and above the moving loading end, respectively.

[0014] Furthermore, the load measurement unit includes a piezoelectric force sensor.

[0015] The present invention may also include:

[0016] A method for medium strain rate impact tensile testing of filamentous materials, using the aforementioned apparatus, includes the following steps:

[0017] First, the two ends of the sample are respectively clamped in the sample fixture above the moving loading end of the pneumatic impact loading system and below the load measuring unit. By shaking the hand crank, the sliding platform is driven to move the load measuring unit up and down precisely to achieve precise centering of the sample and apply a small initial preload. The preload value is monitored in real time by the load measuring unit.

[0018] Subsequently, an external air source and control system are connected, the driving air pressure of the cylinder is set and triggered, and the cylinder piston rod drives the impact head and the moving loading end to move downward at high speed to dynamically stretch the sample. During this process, the laser displacement sensor records the displacement history of the moving loading end in real time, and the load measurement unit records the tensile force history borne by the sample in real time.

[0019] Furthermore, after the sample breaks, the remaining kinetic energy of the impact head is effectively absorbed by the buffer protection structure, achieving smooth braking.

[0020] The beneficial effects of this invention are as follows:

[0021] This invention achieves precise fine-tuning and is easy to operate. It solves the problem of inaccurate control of pre-tightening force for thin wire samples by using a hand-cranked screw fine-tuning mechanism, which greatly improves the efficiency of test preparation and the repeatability of results. It can drive the fixed clamping end to make fine position adjustments to achieve sample centering and pre-tightening.

[0022] This invention achieves self-protection, stability, and reliability. The specially designed elastic buffer protection module can effectively avoid rigid collisions between the impact head and the base, has a self-protection function, significantly reduces equipment wear, extends service life, and ensures the stability of long-term testing.

[0023] This invention features an integrated structure with strong adaptability. It adopts a modular design, resulting in a compact structure and clear functions. The clamping end has a reserved standard interface, allowing for quick fixture replacement and adapting to the testing needs of various materials, from polymer fibers to metal filaments.

[0024] This invention provides accurate data by using a high-frequency resonant pressure electric sensor to directly measure force signals, combined with non-contact laser displacement measurement, resulting in high synchronization accuracy and ensuring the accuracy of stress-strain data derivation under moderate strain rates. Attached Figure Description

[0025] Appendix Figure 1 This is a schematic diagram of the structure of the present invention;

[0026] Appendix Figure 2 This is a schematic diagram of the pneumatic impact loading system of the present invention;

[0027] Appendix Figure 3 This is a schematic diagram of the rigid base support structure of the present invention;

[0028] Appendix Figure 4 This is a schematic diagram of the displacement fine-tuning system of the present invention.

[0029] In the attached diagram: 1. Rigid base support; 1-1. Base; 1-2. Column; 1-3. Top beam; 1-4. Sliding platform; 1-5. Support; 1-6. Reinforcing base; 1-7. Reinforcing column.

[0030] 2. Pneumatic impact loading system, 2-1. Cylinder, 2-2. Impact head, 2-3. Connecting rod, 2-4. Moving loading end;

[0031] 3. Pneumatic impact loading system, 3-1 laser displacement sensor, 3-2 hand crank, 3-3 lead screw;

[0032] 4. Load measurement unit;

[0033] 5. Impact buffer protection structure

[0034] 6. Sample pieces. Detailed Implementation

[0035] The present invention will now be further described with reference to the accompanying drawings.

[0036] This invention provides a medium strain rate impact tensile testing apparatus for filamentous materials, as shown in the attached diagram. Figure 1 As shown, it includes: a rigid base support 1, on which a pneumatic impact loading system 2 and a displacement fine-tuning system 3 are installed. The pneumatic impact loading system 2 is located below the displacement fine-tuning system 3. An impact buffer protection structure 5 is located below the pneumatic impact loading system 2. The displacement fine-tuning system 3 is connected to a load measuring unit 4 below. A sample 6 is installed between the load measuring unit 4 and the pneumatic impact loading system 2.

[0037] The rigid base support 1 serves as a load-bearing platform, providing rigid support for the entire device.

[0038] The displacement fine-tuning system 3 enables precise adjustment of the initial state.

[0039] The impact buffer protection structure 5 is located at the end of the motion path of the pneumatic impact loading system 2 and is used to absorb the residual impact energy after the sample breaks.

[0040] Specifically, the buffer protection module 5 is installed on the base 1-1 directly below the impact head 2-2.

[0041] Preferably, the buffer protection structure 5 is a buffer block made of high-performance polyurethane material.

[0042] As attached Figure 2 As shown, the pneumatic impact loading system 2 includes a movable loading end 2-4 and a cylinder 2-1. Two parallel connecting rods 2-3 are installed below the movable loading end 2-4. The piston rod of the cylinder 2-1 is vertically downward and connected to the impact head 2-2. The impact head 2-2 is movably mounted on the connecting rods 2-3.

[0043] In this embodiment, the pneumatic impact loading system 2 can slide up and down along the connecting rod 2-3 to accommodate different sample lengths. The system includes a cylinder 2-1, an impact head 2-2, and a moving loading end 2-4. The cylinder body of the cylinder 2-1 is fixed, and its piston rod is vertically downward and rigidly connected to the impact head 2-2 via a thread.

[0044] As attached Figure 3As shown, the rigid base support 1 includes a top beam 1-3 and a base 1-1. A column 1-2 is installed between the top beam 1-3 and the base 1-1. A sliding platform 1-4 is slidably fitted on the column 1-2. A fixed support 1-5 and a reinforcing seat 1-6 are sequentially fixedly installed on the column 1-2 below the sliding platform 1-4. Multiple reinforcing columns 1-7 are installed between the support 1-5 and the base 1-1, and the reinforcing columns 1-7 pass through the reinforcing seat 1-6.

[0045] In this embodiment, the rigid base support 1 constitutes the load-bearing main body of the device, which is formed by a base 1-1, two vertical columns 1-2 fixed to both ends of the base, and a top beam 1-3 connecting the tops of the two columns, together forming a stable gantry frame. A sliding platform 1-4, which can slide up and down along the two columns 1-2 and can be fixed by locking devices, is fitted onto the two columns 1-2. Supports 1-5 and reinforcing seats 1-6 for supporting the loading system are also fixed on the base 1-1, and the two are reinforcedly connected to the base by multiple reinforcing columns 1-7.

[0046] As attached Figure 4 As shown, the displacement fine-tuning system 3 includes a lead screw 3-3, which is vertically mounted between the top beam 1-3 and the sliding platform 1-4 via bearings. A hand crank 3-2 is mounted on the top of the lead screw 3-3, and the sliding platform 1-4 is engaged at the bottom of the lead screw 3-3 via a threaded pair. Rotating the hand crank 3-2 can drive the sliding platform 1-4 to precisely rise and fall along the column 1-2.

[0047] A laser displacement sensor 3-1 is installed on the column 1-2. The laser displacement sensor 3-1 is located on one side of the sample 6. The emitting head of the laser displacement sensor 3-1 is horizontally aligned with the reflector on the side of the moving loading end 2-4.

[0048] Preferably, the laser displacement sensor 3-1 is mounted on a column 1-2 via a magnetic base with locking function.

[0049] The load measuring unit 4 is a high-frequency response piezoelectric force sensor 3-4. The sensor is vertically fixed to the lower part of the sliding platform 1-4 by threads, and the lower end of the sensor is provided with a standard threaded hole for installing the sample fixture.

[0050] Sample clamps are installed below the load measuring unit 4 and above the moving loading ends 2-4, respectively.

[0051] This embodiment also provides a method for medium strain rate impact tensile testing of filamentous materials, using the above-described apparatus, and the method includes the following steps:

[0052] First, the two ends of the sample piece 6 are respectively clamped in the sample piece fixture above the moving loading end 2-4 of the pneumatic impact loading system 2 and below the load measuring unit. By shaking the hand crank end 3-2, the sliding platform 1-4 is driven to move the load measuring unit up and down precisely to achieve precise centering of the sample piece and apply a small initial preload. The preload value is monitored in real time by the load measuring unit.

[0053] Subsequently, an external air source and control system are connected, the driving air pressure of cylinder 2-1 is set (typically corresponding to an impact velocity of 1-5 m / s), and the system is triggered. The cylinder piston rod drives the impact head 2-2 and the moving loading end 2-4 to move downwards at high speed, applying dynamic tension to the sample. During this process, the laser displacement sensor 3-1 records the displacement history of the moving loading end 2-4 in real time, and the load sensor 3-4 records the tensile force history borne by the sample in real time. After the sample breaks, the remaining kinetic energy of the impact head 2-2 is effectively absorbed by the buffer block 2-5, achieving smooth braking. Finally, the load-displacement signal synchronously recorded by the external high-speed data acquisition card is processed by computer software to obtain the dynamic tensile stress-strain curve of the material at a specific strain rate.

[0054] By changing the force sensor with different ranges, the type of clamp, and adjusting the material and hardness of the buffer blocks 2-5, this device can be widely used for dynamic performance testing of various filamentous materials.

[0055] This invention enables precise centering and pre-tightening of filamentous specimens, reliable testing within an impact velocity range of 1-5 m / s (impact velocity can be scaled up according to the proportional dimensions of the structure), and effectively absorbs residual impact energy to protect the equipment, thereby obtaining accurate dynamic stress-strain data of the material.

[0056] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A device for medium strain rate impact tensile testing of filamentous materials, characterized in that, include: A rigid base support (1) is provided, on which a pneumatic impact loading system (2) and a displacement fine-tuning system (3) are installed. The pneumatic impact loading system (2) is located below the displacement fine-tuning system (3). An impact buffer protection structure (5) is located below the pneumatic impact loading system (2). The displacement fine-tuning system (3) is connected to a load measuring unit (4). A sample (6) is installed between the load measuring unit (4) and the pneumatic impact loading system (2). The pneumatic impact loading system (2) includes a movable loading end (2-4) and a cylinder (2-1). Two parallel connecting rods (2-3) are installed below the movable loading end (2-4). The piston rod of the cylinder (2-1) is vertically connected to the impact head (2-2). The impact head (2-2) is movably mounted on the connecting rod (2-3).

2. The apparatus for medium strain rate impact tensile testing of filamentous materials according to claim 1, characterized in that, The rigid base support (1) includes a top beam (1-3) and a base (1-1). A column (1-2) is installed between the top beam (1-3) and the base (1-1). A sliding platform (1-4) is slidably fitted on the column (1-2). A fixed support (1-5) and a reinforcing seat (1-6) are sequentially fixedly installed on the column (1-2) below the sliding platform (1-4). Multiple reinforcing columns (1-7) are installed between the support (1-5) and the base (1-1). The reinforcing columns (1-7) pass through the reinforcing seat (1-6).

3. The apparatus for medium strain rate impact tensile testing of filamentous materials according to claim 1, characterized in that, The displacement fine-tuning system (3) includes a lead screw (3-3), which is vertically installed between the top beam (1-3) and the sliding platform (1-4) via a bearing. A hand crank end (3-2) is installed at the top of the lead screw (3-3), and the sliding platform (1-4) at the bottom of the lead screw (3-3) is engaged by a threaded pair.

4. The apparatus for medium strain rate impact tensile testing of filamentous materials according to claim 3, characterized in that, A laser displacement sensor (3-1) is installed on the column (1-2). The laser displacement sensor (3-1) is located on one side of the sample (6). The emitting head of the laser displacement sensor (3-1) is horizontally aligned with the reflector on the side of the moving loading end (2-4).

5. The apparatus for medium strain rate impact tensile testing of filamentous materials according to claim 1, characterized in that, The buffer protection module (5) is installed on the base (1-1) directly below the impact head (2-2).

6. The apparatus for medium strain rate impact tensile testing of filamentous materials according to claim 6, characterized in that, The buffer protection structure (5) is a buffer block made of high-performance polyurethane material.

7. The apparatus for medium strain rate impact tensile testing of filamentous materials according to claim 1, characterized in that, Sample clamps are installed below the load measuring unit (4) and above the moving loading end (2-4).

8. The apparatus for medium strain rate impact tensile testing of filamentous materials according to claim 1, characterized in that, The load measurement unit includes a piezoelectric force sensor (3-4).

9. A method for medium strain rate impact tensile testing of filamentous materials, characterized in that, The method using the apparatus according to any one of claims 1-8 comprises the following steps: First, the two ends of the sample (6) are respectively clamped in the sample fixture above the moving loading end (2-4) of the pneumatic impact loading system (2) and below the load measuring unit. By shaking the hand crank end (3-2), the sliding platform (1-4) is driven to move the load measuring unit up and down precisely to achieve precise centering of the sample and apply a small initial preload. The preload value is monitored in real time by the load measuring unit. Subsequently, the external air source and control system are connected, the driving air pressure of the cylinder (2-1) is set and triggered, and the cylinder piston rod of the cylinder (2-1) drives the impact head (2-2) and the moving loading end (2-4) to move downward at high speed to perform dynamic tension on the sample. During this process, the laser displacement sensor (3-1) records the displacement history of the moving loading end (2-4) in real time, and the load measurement unit (4) records the tensile force history borne by the sample in real time. Finally, the load-displacement signal synchronously recorded by the external high-speed data acquisition card is processed by computer software to obtain the dynamic tensile stress-strain curve of the material at a specific strain rate.

10. The method for medium strain rate impact tensile testing of filamentous materials according to claim 9, characterized in that, After the sample (6) breaks, the remaining kinetic energy of the impact head (2-2) is effectively absorbed by the buffer protection structure (6), achieving smooth braking.

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