Clamp for testing high-speed tensile mechanical property of connecting thin plate

Abstract

The utility model discloses a high-speed tensile mechanical property test fixture for a connecting thin plate, which comprises an upper chuck and a lower chuck which are oppositely arranged, sinking tables are arranged in the middle positions of the end surfaces of the upper chuck and the lower chuck, sample fixing bolt holes are formed in the upper chuck and the lower chuck, and the upper chuck and the lower chuck are arranged in a complete set; the upper clamping head and the lower clamping head are clamped and installed on respective tool clamping pieces through connecting rods, and the clamping parts of the connecting rods are taper shafts matched with the tool clamping pieces. A matched clamp is machined according to a scale factor of a tension-shear combination, one set of clamp corresponds to a joint under one working condition to perform mechanical property testing, the influence caused by excessive clearance fit can be avoided, and the problem that a test tool cannot be effectively fixed, so that errors are generated in a test is solved; by matching with a wedge-shaped clamping block of a high-speed tensile testing machine, the round bar part of the chuck is processed into a taper shaft, and the translation of the clamp in the axis direction in the tensile process is limited, so that the rigid displacement of the clamp in the high-speed tensile process is avoided.

Description

Technical Field

[0001] The utility model relates to the technical field of dynamic mechanical performance testing, in particular to a clamp for connecting thin plates for high-speed tensile mechanical performance testing. Background Art

[0002] In the automotive, aerospace and other manufacturing industries, a variety of processes are used to connect thin plates, such as resistance spot welding, laser welding, stir friction welding, bolting, riveting, hot melt self-tapping, self-piercing riveting, adhesive bonding, etc. When selecting a connection process, parameters such as economy and mechanical properties are crucial. Therefore, testing the mechanical properties of connected thin plates through experiments has become one of the important means to evaluate the performance of different connection processes. As a means of mechanical property testing, high-speed tensile testing can effectively evaluate the dynamic mechanical performance response of different connection processes under high-speed conditions, including coefficients, strength, stiffness, and fracture mode. This provides an important reference for selecting a connection process.

[0003] At present, the common mechanical properties test fixture design usually only considers quasi-static loading conditions, and has limitations in its application under dynamic conditions: the connected thin plates usually show obvious strain rate effect under dynamic conditions, that is, the connection strength increases with the increase of tensile rate. Conventional measurement fixtures only rely on the wedge block of the tensile tester to clamp the round bar part of the fixture, which cannot effectively fix the test fixture, and thus easily produce errors in obtaining the response of the joint mechanical properties. Fig.10 , Fig.11 The fixture shown can perform tensile, shear and combined tensile and shear tests on the connected thin plates under various scale factors by adjusting the fixture's installation position on the angle plate. The assembly process of the fixture is relatively cumbersome, and each test requires disassembly of the middle part of the fixture and bolt tightening. In addition, the clearance fit of the fixture angle plate introduces additional failure displacement, which is coupled with the actual deformation of the joint, affecting the measurement accuracy. If there are too many clearance fit holes, the connection stiffness shown in the joint mechanical property test may be less than the actual stiffness. Utility Model Content

[0004] In view of the defects of the above-mentioned prior art, the technical problem to be solved by the utility model is to provide a corresponding chuck made according to different working conditions, so as to solve the problem of being unable to effectively fix the test tooling, while avoiding the influence of excessive clearance fit, and limiting the translational movement of the fixture in the axial direction during the stretching process. A high-speed tensile mechanical properties test fixture for connecting thin plates.

[0005] In order to solve the above technical problems, the utility model adopts the following technical solutions: a high-speed tensile mechanical property testing fixture for connecting thin plates, comprising an upper chuck and a lower chuck arranged relatively to each other, and a sinking platform is arranged at the center position of the end faces of the upper chuck and the lower chuck, and a sample fixing bolt hole is arranged on the upper chuck and the lower chuck, and the upper chuck and the lower chuck are provided with a set of at least four sets, and the working surfaces of the four sets are respectively 0°, 30°, 60°, and 90° to the horizontal plane, and are respectively used to test the mechanical properties of the connected thin plates under 90° tensile conditions, 60° tension-shear combined conditions, 30° tension-shear combined conditions, and 0° shear conditions; the upper chuck and the lower chuck are both clamped and installed on their respective tooling clamps through a connecting rod, and the clamping portion of the connecting rod is a tapered shaft matching the tooling clamp, and the end of the tapered shaft close to the tooling clamp is the large diameter.

[0006] Preferably, a pair of sample fixing bolt holes are provided on the upper chuck and the lower chuck.

[0007] Preferably, the upper chuck and the lower chuck are "L"-shaped chucks in the 0° shear condition.

[0008] Preferably, the connecting rod is a cylindrical rod.

[0009] Preferably, the upper clamp, the lower clamp and their corresponding connecting rods are integrally formed and cut to ensure overall structural strength.

[0010] The beneficial effects of the utility model are as follows: a matching fixture is processed according to the proportional factor of the tension-shear combination, and a set of fixtures is used to test the mechanical properties of a joint under one working condition, which can avoid the influence of excessive clearance fit and solve the problem of being unable to effectively fix the test fixture, thereby causing errors in the test; in conjunction with the wedge-shaped clamp block of the high-speed tensile testing machine, the round rod part of the clamp is processed into a tapered shaft to limit the translational movement of the fixture in the axial direction during the stretching process, so as to avoid the rigid displacement of the fixture during the high-speed stretching process. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a structural schematic diagram of a high-speed tensile testing machine;

[0012] Figure 2 It is a schematic diagram of the structure of the chuck in the 90° tensile working condition;

[0013] Figure 3 It is a schematic diagram of the overlap of the specimen under 90° tensile condition;

[0014] Figure 4 It is a schematic diagram of the structure of the chuck for 60° tension-shear composite working condition;

[0015] Figure 5 This is a schematic diagram of the overlap of the 60° tension-shear composite working condition specimen;

[0016] Figure 6 It is a schematic diagram of the structure of the chuck for 30° tension-shear composite working condition;

[0017] Figure 7 This is a schematic diagram of the overlap of the specimen under 30° tension-shear composite working condition;

[0018] Figure 8 It is a schematic diagram of the structure of the chuck in 0° shearing condition;

[0019] Fig. 9 It is the schematic diagram of the overlap of the specimen under 0° shear condition;

[0020] Fig.10 It is a schematic diagram of the structure of a conventional measuring fixture;

[0021] Fig.11 is the schematic diagram of the overlap of the specimen;

[0022] In the figure: 1- tooling clamp, 2- upper chuck, 3- specimen fixing bolt hole, 4- lower chuck, 5- connecting rod, a- sinking table. DETAILED DESCRIPTION

[0023] In order to better understand the improvements made by the present invention relative to the prior art, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments.

[0024] like Figure 1 As shown, a high-speed tensile mechanical property test fixture for connecting thin plates is mainly composed of an upper clamp 2 and a lower clamp 4 that are arranged opposite to each other.

[0025] A sink a is provided at the center of the end surface of the upper chuck 2 and the lower chuck 4. When the connecting thin plates are connected by a riveted joint, the riveted joint is located in the sink a. At the same time, a pair of sample fixing bolt holes 3 are provided on the upper chuck 2 and the lower chuck 4.

[0026] The thin plate sample is fastened to the corresponding upper clamp 2 or lower clamp 4 by bolts.

[0027] like Figure 2 As shown in FIG. 9 , the upper chuck 2 and the lower chuck 4 are provided as a set, and chucks with different working surface angles can be processed according to the proportional factor of the tension-shear combination, so as to avoid the influence of excessive clearance fit as much as possible. In the high-speed tensile mechanical property test, at least four sets are provided, and the working surfaces of the four sets are 0°, 30°, 60°, and 90° to the horizontal plane, respectively, and are used to test the mechanical properties of the connected thin plates under 90° tensile conditions, 60° tension-shear combined conditions, 30° tension-shear combined conditions, and 0° shear conditions, respectively. The upper chuck 2 and the lower chuck 4 are "L"-shaped chucks under the 0° shear condition.

[0028] The upper chuck 2 and the lower chuck 4 are clamped and installed on their respective tooling clamps 1 through a connecting rod 5, and the connecting rod 5 is a cylindrical rod. In order to ensure the overall structural strength of the clamp, the upper chuck 2, the lower chuck 4 and the corresponding connecting rod 5 are all integrally formed and cut, and the connection between the connecting rod 5 and the chuck is provided with a rounded corner to reduce stress concentration. In order to limit the translation of the clamp in the axial direction during the stretching process, the clamping part of the connecting rod 5 is a tapered shaft that matches the tooling clamp 1, and the end of the tapered shaft close to the tooling clamp 1 is a large diameter, which can avoid the rigid displacement of the clamp during high-speed stretching.

[0029] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes within the technical scope disclosed by the present invention according to the technical scheme and the utility model concept of the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A clamp for testing the mechanical properties of a connecting plate under high-speed tensile stress, comprising an upper clamp (2) and a lower clamp (4) arranged opposite to each other, wherein a sink (a) is arranged at the center of the end surface of the upper clamp (2) and the lower clamp (4), and a sample fixing bolt hole (3) is arranged on the upper clamp (2) and the lower clamp (4), wherein: The upper chuck (2) and the lower chuck (4) are arranged in a set, and at least four sets are arranged. The working surfaces of the four sets are respectively 0°, 30°, 60°, and 90° to the horizontal plane, and are respectively used to test the mechanical properties of the connected thin plates under 90° tensile conditions, 60° tension-shear combined conditions, 30° tension-shear combined conditions, and 0° shear conditions; the upper chuck (2) and the lower chuck (4) are both clamped and installed on their respective tooling clamps (1) through a connecting rod (5), and the clamping portion of the connecting rod (5) is a tapered shaft matching the tooling clamp (1), and the end of the tapered shaft close to the tooling clamp (1) has a large diameter.

2. A high-speed tensile mechanical properties test fixture for connecting thin plates according to claim 1, characterized in that: A pair of sample fixing bolt holes (3) are provided on the upper clamp (2) and the lower clamp (4).

3. A high-speed tensile mechanical properties test fixture for connecting thin plates according to claim 1, characterized in that: The upper chuck (2) and the lower chuck (4) are "L"-shaped chucks in a 0° shearing condition.

4. A high-speed tensile mechanical properties test fixture for connecting thin plates according to claim 1, characterized in that: The connecting rod (5) is a cylindrical rod.

5. The high-speed tensile mechanical properties test fixture for connecting thin plates according to claim 1, characterized in that: The upper clamp (2), the lower clamp (4) and the corresponding connecting rods (5) are all integrally formed and cut.

6. A high-speed tensile mechanical property test fixture for connecting thin plates according to claim 5, characterized in that: The connection between the connecting rod (5) and the clamp is provided with a rounded corner to reduce stress concentration.

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