Low-damage thin plate tensile test device

Abstract

The invention provides a low-damage thin plate tensile test device, which comprises: two fixing heads, which are used for clamping two end parts of a thin plate sample and are internally provided with a mounting groove for placing the thin plate sample; the at least two limiting rollers are located in the mounting groove of the fixing head and rotationally connected with the fixing head, and the two ends of each limiting roller are in sliding connection with the inner wall of the mounting groove; the limiting assemblies are fixed at the two ends of the limiting roller and drive the limiting roller to abut against the fixed side wall of the thin plate sample; and the pressurizing assembly comprises a limiting part which is mounted in the mounting groove, and further comprises a driving assembly which is connected with the limiting part, drives the limiting part to slide towards the direction of the limiting roller and limits rotation of the limiting roller. According to the technical scheme, the sheet sample is limited and extruded by the limiting roller, so that the fixing head and the sheet sample are connected and limited.

Description

Technical Field

[0001] The present invention generally relates to the field of mechanical property testing of metal materials, and particularly relates to a low-damage thin plate tensile test device. Background Art

[0002] As an important structural material in the fields of automobiles, aerospace, etc., the accurate testing of the mechanical properties (such as tensile strength, yield point, etc.) of metal thin plates is a key link in material research and development and quality control. However, there are generally the following technical bottlenecks in the existing testing machine fixtures when clamping thin plate specimens.

[0003] For example, a sheet material tensile test device and its fixed head disclosed in the publication number CN207636410U. It includes a fixed head, and a connecting portion connected to the specimen is provided on the fixed head. The connecting portion has an inner cavity for the specimen to extend into, and a pin hole for inserting a fixing pin is provided on the side surface of the connecting portion. The pin hole is an oblong hole arranged along the specimen tensile direction.

[0004] The inventor believes that if the above method is used to install and fix the thin plate specimen with a fixing pin, for a thin plate specimen with a relatively thin thickness, there is a situation of tearing from the pin hole, rather than breaking in the test area, which is likely to cause inaccurate test results. Summary of the Invention

[0005] In view of the problems existing in the above-mentioned prior art according to the present invention, a low-damage thin plate tensile test device is provided, including: two fixed heads, which are used to clamp the two ends of the thin plate specimen, and an installation groove for placing the thin plate specimen is opened therein; at least two limiting rollers, which are located in the installation groove of the fixed head and are rotatably connected to the fixed head, and both ends thereof are slidably connected to the inner wall of the installation groove; a limiting component, which is fixed at both ends of the limiting roller and drives the limiting roller to abut against the fixed side wall of the thin plate specimen; a pressurizing component, including a limiting member, which is installed in the installation groove, and further includes a driving component, which is connected to the limiting member and drives the limiting member to slide towards the limiting roller direction to limit the rotation of the limiting roller. By having the above technical features, during the process of inserting the thin plate specimen into the installation groove of the fixed head, the limiting roller extrudes the thin plate specimen under the action of the limiting component. On the one hand, it guides the thin plate specimen, making the thin plate specimen fit more closely with the inner wall of the installation groove. Finally, the driving component drives the displacement of the limiting member to limit the rotation and extrusion of the limiting roller, so that the limiting roller tightly presses against the thin plate specimen, restricting the separation of the thin plate specimen from the inner wall of the installation groove.

[0006] In some embodiments, the limiting roller includes a rotating part in the middle, a flexible friction part sleeved on the peripheral side of the rotating part, and a limiting shaft coaxially fixed to both ends of the rotating part. As a result, the rotating part can guide the thin plate sample by rotating itself during the thin plate sample penetration, and also reduce the mutual friction between the thin plate sample and the flexible friction part, and during the thin plate sample penetration, the flexible friction part can reduce the mutual friction between the flexible friction part and the thin plate sample by rotating the rotating part. When the thin plate sample is fixed and limited, it can increase the contact area with the thin plate sample by squeezing, improve the stability of the force on the thin plate sample, and also increase the friction with the thin plate sample, improving the fixing effect of the thin plate sample.

[0007] In some embodiments, the limiting assembly includes a spring, one end of which is fixed to the inner wall of the installation slot; an extrusion block, which is fixed to the other end of the spring and abuts against the limiting shaft, driving the flexible friction part to abut against the side wall for fixing the thin plate sample. Therefore, when the thin plate sample is inserted into the installation slot, the limiting roller will slide and give way with the inner wall of the installation slot, and the spring will be elastically deformed to accumulate elastic potential energy, so that the displacement of the thin plate sample is more stable.

[0008] In some embodiments, the rotating part includes a metal support shaft, and the limiting shaft is coaxially fixed to the two ends of the metal support shaft; it also includes a plastic sleeve, which is coaxially fixed to the circumference of the metal support shaft, and the flexible friction part is sleeved on the circumference of the plastic sleeve. As a result, the metal support shaft provides strong support for the limiting roller, ensuring the overall mechanical strength of the limiting roller. The plastic sleeve is prone to deformation under greater stress, thereby increasing the contact area with the thin plate sample, improving the contact range between the limiting roller and the thin plate sample, and avoiding the tearing of the thin plate sample caused by uneven force due to the large local stress of the thin plate sample.

[0009] In some embodiments, the circumference of the plastic sleeve is uniformly provided with a plurality of deformation grooves along its length direction, and the deformation grooves are filled with elastic diffusion strips. Thus, the deformation grooves are located on the circumference of the plastic sleeve, and under the action of a large stress, the deformation groove area is prone to deformation, thereby increasing the contact area with the thin plate specimen, and the elastic diffusion strips filled therein can fill the gaps while also ensuring the uniformity of the force on the thin plate specimen.

[0010] In some embodiments, a rigid support strip is embedded on the side of the elastic diffusion strip away from the metal support shaft. Therefore, the rigid support strip has high mechanical strength and is not easy to deform, which can not only avoid damage to the plastic sleeve caused by excessive deformation space of the deformation groove, but also increase the extrusion pressure on the strip area when it is pressed on the thin plate sample, thereby ensuring the stability of the thin plate sample fixation.

[0011] In some embodiments, the cross-section of the rigid support bar is elliptical spherical. Thus, the middle region of the rigid support bar is thicker and not easily deformed, while the two ends are thinner and easily deformed under the influence of external stress; as the rigid support bar deforms, the contact area with the thin plate specimen is further increased, and under the cushioning of the flexible friction part, the pressure of the thin plate specimen becomes more balanced.

[0012] In some embodiments, an elastic keel is arranged between each deformation groove and the metal support shaft, and the elastic keel is fixed within the plastic sleeve. Thus, after the plastic sleeve deforms, the elastic keel deforms and restores its own shape, which helps the deformation groove of the plastic sleeve to return to its original position, thereby ensuring the service life of the limit roller.

[0013] In some embodiments, the driving assembly includes a threaded rod, one end of which is rotatably connected to the limiting member, and the other end is threadedly connected to the fixed head and penetrates through the side wall of the fixed head; it further includes a screwing part, which is fixed to the end area of the threaded rod outside the fixed head. Thus, the threaded rod can be rotated by hand, so that the limiting member presses against the periphery of the limit roller, which can not only push the limit roller to displace, but also restrict the rotation of the limit roller, ensuring the limiting effect of the limit roller on the thin plate specimen.

[0014] In some embodiments, the cross-section of the deformation groove is an arc-shaped groove. Thus, the deformation groove is a smooth curved surface, and when the deformation groove is deformed by force, it is not easy to cause a structural impact on the plastic sleeve.

[0015] It should be understood that the content described in the summary of the invention is not intended to limit the key or important features of the embodiments of the present disclosure, nor is it used to limit the scope of the present disclosure. Other features of the present disclosure will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Shows the overall structural schematic diagram of a low-damage thin plate tensile test device according to an embodiment of the present invention.

[0017] Figure 2 Shows the cross-sectional structural schematic diagram of a low-damage thin plate tensile test device according to an embodiment of the present invention.

[0018] Figure 3 Shows the overall structural schematic diagram of a limit roller in a low-damage thin plate tensile test device according to an embodiment of the present invention.

[0019] Figure 4 Shows the internal structural schematic diagram of the slideway in a low-damage thin plate tensile test device according to an embodiment of the present invention.

[0020] Figure 5The schematic structural diagram of the pressurizing component in a low-damage thin plate tensile test device according to an embodiment of the present invention is shown.

[0021] Figure 6 The schematic cross-sectional structure diagram of the limiting roller in a low-damage thin plate tensile test device according to an embodiment of the present invention is shown.

[0022] Symbol description 1. Fixed head; 11. Fixed section; 111. Installation groove; 112. Slideway; 12. Connection section; 2. Thin plate specimen; 21. Test section; 22. Fixed end; 3. Limiting roller; 31. Rotating part; 311. Metal support shaft; 312. Plastic sleeve; 3121. Deformation groove; 32. Flexible friction part; 33. Limiting shaft; 4. Pressurizing component; 41. Limiting piece; 42. Threaded rod; 43. Screwing part; 5. Limiting component; 51. Spring; 52. Extrusion block; 6. Elastic diffusion strip; 7. Rigid support strip; 8. Elastic keel. Detailed implementation manners

[0023] Next, the preferred embodiments (or implementation manners) of the present invention will be described in detail with reference to the accompanying drawings.

[0024] Next, refer to Figures 1-6 to describe a low-damage thin plate tensile test device of the present invention.

[0025] Figure 1 The schematic overall structure diagram of a low-damage thin plate tensile test device according to an embodiment of the present invention is shown. Refer to Figure 1 As shown, a low-damage thin plate tensile test device provided in this embodiment includes two fixed heads 1. The fixed head 1 includes a fixed section 11 and a connection section 12 located at the tail of the fixed section 11. The thin plate specimen 2 includes a test section 21 in the middle and fixed ends 22 located at both ends of the test section 21. The fixed section 11 of the fixed head 1 is used to clamp and fix the fixed end 22 of the thin plate specimen 2, and the connection section 12 of the fixed head 1 is used to be fixedly connected with the testing machine.

[0026] Figure 2 The schematic cross-sectional structure diagram of a low-damage thin plate tensile test device according to an embodiment of the present invention is shown. Refer to Figure 2 As shown, an installation groove 111 is opened on the side of the fixed section 11 facing away from the connection section 12 for inserting and limiting the fixed end 22 of the thin plate specimen 2 therein. At least two limiting rollers 3 are arranged in the fixed section 11. The limiting rollers 3 are arranged along the width direction of the installation groove 111, and both ends thereof are slidably connected with the inner wall of the installation groove 111 along the height direction of the installation groove 111; and a pressurizing component 4 for driving the limiting roller 3 to displace towards the bottom wall of the installation groove 111 and restricting the rotation of the limiting roller 3 is arranged in the top region of each limiting roller 3.

[0027] Figure 3 The figure shows a schematic diagram of the overall structure of a limiting roller in a low-damage thin plate tensile test device according to an embodiment of the present invention. Refer to Figure 3 As shown, the limiting roller 3 includes a rotating part 31 with a cylindrical shape in the middle, and a flexible friction part 32 coaxially fixed on the peripheral side of the rotating part 31. The flexible friction part 32 is a tube made of flexible rubber material, which can increase the friction force with the contact area through its own deformation, so as to play a limiting role. At both ends of the rotating part 31, a limiting shaft 33 is coaxially fixed. Along the height direction of the inner wall of the installation groove 111, a slideway 112 is opened. The end of the limiting shaft 33 penetrates into it, so as to meet the rotation of the limiting roller 3 itself and the sliding along the direction of the slideway 112.

[0028] Figure 4 The figure shows a schematic diagram of the internal structure of the slideway in a low-damage thin plate tensile test device according to an embodiment of the present invention. Refer to Figure 4 As shown, a limiting component 5 is further arranged above the limiting shaft 33 in the slideway 112. The limiting component 5 includes a spring 51. The spring 51 is arranged along the length direction of the slideway 112. The upper end of the spring 51 is fixed to the upper wall of the slideway 112, and the lower end of the spring 51 is fixedly connected with a pressing block 52. The pressing block 52 is located in the slideway 112 and is slidably connected with the inner wall of the slideway 112 along the length direction of the slideway 112. Under the elastic action of the spring 51, the pressing block 52 is driven to slide downward, and the pressing block 52 abuts against the limiting shaft 33 and drives the rotating part 31 in the middle to press against the bottom wall of the installation groove 111, so that the flexible friction part 32 closely abuts against the bottom wall of the installation groove 111. When fixing the thin plate specimen 2, with the mutual insertion of the thin plate specimen 2 and the installation groove 111, the limiting roller 3 is driven to slide along the height direction of the slideway 112, and the elastic deformation of the spring 51 accumulates elastic acting force, so that the thin plate specimen 2 always abuts against the bottom wall of the installation groove 111 and is inserted into the bottom of the installation groove 111 smoothly. On the one hand, with the insertion of the thin plate specimen 2, the rotation of the limiting roller 3 will be driven to reduce the friction force between the limiting roller 3 and the thin plate specimen 2; on the other hand, under the elastic acting force applied by the limiting roller 3, it plays a guiding role for the thin plate specimen 2, ensuring that the thin plate specimen 2 is inserted into the fixed area of the fixed section.

[0029] In some embodiments, the lower surface of the pressing block 52 is an arc surface that cooperates with the limiting shaft 33, thereby increasing the contact area between the pressing block 52 and the limiting shaft 33, ensuring the stability of the rotation of the limiting shaft 33, and with the elastic deformation of the spring 51, the elastic acting force on the pressing block 52 also increases, indirectly increasing the friction force between the pressing block 52 and the limiting shaft 33, restricting the smooth rotation of the limiting shaft 33, and making the insertion of the thin plate specimen 2 slower and more stable.

[0030] Figure 5 The structural schematic diagram of the pressurizing assembly 4 in a low-damage thin plate tensile test device according to an embodiment of the present invention is shown. As shown in reference 5, the pressurizing assembly 4 includes a limiting member 41. The limiting member 41 is a strip-shaped plate body, which is located on the top of the limiting roller 3 and is arranged along the width direction of the installation groove 111. The two sides of the limiting member 41 are abutted against the side walls on both sides of the installation groove 111. A threaded rod 42 is vertically arranged at its top. The lower end of the threaded rod 42 is rotatably connected to the limiting member 41 around its own center. The upper end of the threaded rod 42 passes through the fixed section 11 and is threadedly connected to the side wall of the fixed section 11. And a screwing part 43 is fixed at the upper end of the threaded rod 42. The screwing part 43 is in the shape of a nut, which is convenient for direct rotation by hand and also convenient for fastening with clamping tools.

[0031] An arc-shaped groove matching with the circumferential side of the limiting roller 3 is formed on the lower surface of the limiting member 41. Thus, when the limiting member 41 and the limiting roller 3 are in contact with each other, on the one hand, the contact area with the limiting roller 3 is increased, making the force on the limiting roller 3 more stable; on the other hand, the friction force between the limiting member 41 and the flexible friction part 32 is increased, thereby restricting the rotation of the limiting roller 3.

[0032] When the fixing head 1 and the thin plate specimen 2 are fixed to each other, first, the fixed end 22 of the thin plate specimen 2 is inserted into the installation groove 111 of the fixed section 11 of the fixing head 1. As the thin plate specimen 2 is inserted, the limiting roller 3 is driven to slide in the slideway 112, and the limiting roller 3 is closely abutted against one side of the thin plate specimen 2, and the thin plate specimen 2 is closely attached to the bottom wall of the installation groove 111. Then, the screwing part 43 at the end of the threaded rod 42 is rotated to drive the limiting member 41 to slide towards the limiting roller 3, and the limiting roller 3 is closely attached to the side wall of the thin plate specimen 2. As the limiting member 41 and the flexible friction part 32 on the circumferential side of the limiting roller 3 are mutually attached, the friction force between the limiting member 41 and the flexible friction part 32 is increased, restricting the rotation of the limiting roller 3, and further increasing the friction force between the limiting roller 3 and the fixed end 22 of the thin plate specimen 2, ensuring the tightness and stability of the connection between the fixing head 1 and the thin plate specimen 2.

[0033] In some embodiments, the bottom wall of the installation groove 111 can be subjected to roughening treatments such as grooving and frosting, or an anti-slip pad can be fixed on the bottom wall of the installation groove 111, so as to increase the unevenness of the bottom wall of the installation groove and improve the friction coefficient of the bottom wall of the installation groove.

[0034] Figure 6 The cross-sectional structural schematic diagram of the limiting roller in a low-damage thin plate tensile test device according to an embodiment of the present invention is shown. Refer to Figure 6As shown, in some embodiments, the rotating part 31 includes a metal support shaft 311 with a cylindrical middle part, and a plastic sleeve 312 coaxially and fixedly connected to the circumferential side of the metal support shaft 311. The flexible friction part 32 is coaxially and fixedly connected to the circumferential side of the plastic sleeve 312, and the limiting shaft 33 is coaxially and fixedly connected to both ends of the metal support shaft 311. The metal support shaft 311 ensures the overall strong support strength of the limiting roller 3. The plastic sleeve 312 can be a tube made of polyamide or a tube made of polyoxymethylene. Polyamide forms hydrogen bonds through amide bonds, has high crystallinity, high strength, wear resistance and self-lubrication, and at the same time has a certain elasticity; while the polyoxymethylene material has both high strength, high rigidity and excellent elasticity; when the plastic sleeve 312 is stressed and extruded, it can bear a large pressure by itself and deform to a certain extent. Under the extrusion of the limiting part 41, the plastic sleeve 312 deforms itself, thereby driving the flexible friction part 32 to spread, further increasing the contact area between the limiting roller 3 and the thin plate specimen 2, and then improving the friction between the limiting roller 3 and the thin plate specimen 2, ensuring the fastening and limiting effect of the limiting roller 3 on the thin plate specimen 2.

[0035] In some embodiments, a plurality of deformation grooves 3121 are uniformly formed on the outer circumferential side of the plastic sleeve 312 along the length direction of the plastic sleeve 312, and an elastic diffusion strip 6 made of rubber material is filled in each deformation groove 3121. On the one hand, under the extrusion of the limiting part 41 on the limiting roller 3, the plastic sleeve 312 is easily deformed and expanded at the edge of the deformation groove 3121, further increasing the overall contact area between the limiting roller 3 and the thin plate specimen 2, and the elastic diffusion strip 6 can fill the gap in the deformation groove 3121, ensuring the uniformity and stability of the pressure on the thin plate specimen 2.

[0036] Furthermore, the cross-section of the deformation groove 3121 is an arc-shaped groove, so that when the plastic sleeve 312 is stressed, the stress transfer in each area is more uniform, and the plastic sleeve 312 is not easily damaged when working under reciprocating pressure.

[0037] In some embodiments, a rigid support bar 7 is embedded on the side of each elastic diffusion bar 6 facing away from the metal support shaft 311. The rigid support bar 7 can be made of metal or rigid plastic material. When the limit roller 3 is stressed, the plastic sleeve 312 deforms under extrusion. Due to the material factor of the rigid support bar 7, it is not easy to deform, and it displaces inward toward the deformation groove 3121 under pressure, causing the excess elastic diffusion bar 6 to overflow from the deformation groove 3121, restricting the deformation angle of the deformation groove 3121 to ensure the service life of the plastic sleeve 312. Moreover, the rigid support bar 7 also indirectly increases the pressure intensity of the contact area of the thin plate specimen 2, thereby increasing the friction force between the limit roller 3 and the thin plate specimen 2. And due to the barrier of the flexible friction part 32, the pressure change in the compressed area of the thin plate specimen 2 is smoother, ensuring the clamping strength and stability between the fixed head 1 and the thin plate specimen 2.

[0038] Further, the cross-section of the rigid support bar 7 is elliptical spherical, such that the thickness of the middle structure is much larger than the thickness of the two side edges. When the plastic sleeve 312 is stressed, the two side edges of the rigid support bar 7 are compressed and deformed, thereby increasing the contact area between the rigid support bar 7 and the thin plate specimen 2, making the pressure received by the thin plate specimen 2 more balanced.

[0039] In some embodiments, an arc-shaped elastic keel 8 is further provided between each deformation groove 3121 and the metal support shaft 311. The bending direction of the elastic keel 8 is the same as the radian direction of the deformation groove 3121, thereby increasing the resilience force of the deformation groove 3121 and further increasing the service life of the plastic sleeve 312.

[0040] In the description of this specification, terms such as "connection", "installation", "fixation" should all be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0041] The above are only the preferred embodiments of this application and are not used to limit this application. For those skilled in the art, this application can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of this application shall be included in the protection scope of this application.

Claims

1. A low-damage thin plate tensile test device, characterized in that, Comprising: Two fixed heads (1) are provided and are used for clamping the two ends of a thin plate specimen (2). An installation groove (111) for placing the thin plate specimen (2) is formed therein. At least two limiting rollers (3) are provided. They are located in the installation groove (111) of the fixed head (1) and are rotatably connected to the fixed head (1). Both ends thereof are slidably connected to the inner wall of the installation groove (111). A limiting assembly (5) is fixed to both ends of the limiting roller (3) and drives the limiting roller (3) to abut against the side wall of the thin plate specimen (2). A pressing assembly (4) includes a limiting member (41) which is installed in the installation groove (111), and further includes A driving assembly which is connected to the limiting member (41), drives the limiting member (41) to slide towards the limiting roller (3), makes the thin plate specimen (2) closely abut against the bottom wall of the installation groove (111), and restricts the rotation of the limiting roller (3).

2. The low-damage thin plate tensile test device according to claim 1, characterized in that, The limiting roller (3) includes a middle rotating portion (31), a flexible friction portion (32) sleeved on the periphery of the rotating portion (31), and limiting shafts (33) coaxially fixed to both ends of the rotating portion (31).

3. The low-damage thin plate tensile test device according to claim 2, characterized in that, The limiting assembly (5) includes A spring (51) whose one end is fixedly connected to the inner wall of the installation groove (111); A pressing block (52) which is fixedly connected to the other end of the spring (51) and abuts against the limiting shaft (33), driving the flexible friction portion (32) to abut against the bottom wall of the installation groove (111).

4. The low-damage thin plate tensile test device according to claim 3, characterized in that, The rotating portion (31) includes A metal support shaft (311), and the limiting shafts (33) are coaxially fixed to both ends of the metal support shaft (311); and further includes A plastic sleeve (312) which is coaxially fixed to the periphery of the metal support shaft (311), and the flexible friction portion (32) is coaxially fixed to the periphery of the plastic sleeve (312).

5. The low-damage thin plate tensile test device according to claim 4, characterized in that, A plurality of deformation grooves (3121) are uniformly formed in the periphery of the plastic sleeve (312) along its length direction, and elastic diffusion strips (6) are filled in the deformation grooves (3121).

6. The low-damage thin plate tensile test device according to claim 5, wherein, A rigid support strip (7) is embedded on the side of the elastic diffusion strip (6) away from the metal support shaft (311).

7. A low-damage thin plate tensile test device according to claim 6, characterized in that, The cross section of the rigid support strip (7) is elliptical spherical.

8. A low-damage thin plate tensile test device according to claim 7, characterized in that, An elastic keel (8) is provided between each deformation groove (3121) and the metal support shaft (311), and the elastic keel (8) is fixed in the plastic sleeve (312).

9. The low-damage thin plate tensile test device according to claim 1, characterized in that, The driving assembly includes A threaded rod (42) whose one end is rotatably connected to the limiting member (41), and the other end is threadedly connected to the fixed head (1) and penetrates through the side wall of the fixed head (1); and further includes A screwing portion (43) which is fixed to the end region of the threaded rod (42) outside the fixed head (1).

10. A low-damage thin plate tensile test device according to claim 5, characterized in that, The cross section of the deformation groove (3121) is an arc-shaped groove.

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