Device and method for testing shear strength of layered composite plate material

Abstract

The invention discloses a device and a method for testing the shear strength of a layered composite material. The device comprises an upper die, a lower die, a gland, a punch carrier, a punch, positioning pins, a fastening spring, a gasket and fastening bolts. The punch carrier, the punch and the gland are elliptic cylinders; two bolt holes and two positioning pin holes are formed in the same position of each of the punch carrier, the punch and the gland; through alignment fixation of the positioning pins, the bolts and the fastening spring, the punch carrier, the punch and the gland are combined into a punch die; a sample is arranged between the punch and the gland; and the edge of the punch is a cutting edge. Compared with an existing device for the shear strength of the layered composite plate material, the device has the advantages that the preparation of the sample is simple; the application range of the thickness of the sample is wide; the shear strength of different thicknessescan be accurately measured; the assembling of the dies is relatively convenient; and meanwhile, due to the fact that a base is omitted, the cost and the material are saved.

Description

technical field [0001] The invention belongs to the technical field of mechanical properties of layered composite boards, and is applicable to the shear strength test of double-layer metal composite boards and the shear strength of three-layer or even multi-layer metal composite boards. Background technique [0002] There are many indicators to measure the quality of layered composite panels. The common indicators include shear strength, bond strength, bending, peeling strength, etc. These indicators can effectively reflect the interface bonding quality of layered composite panels. Among them, the shear strength can effectively explain the interfacial bonding strength of the layered composite plate, and it is also easy to measure, so it is widely used. [0003] The shear strength is calculated according to the formula (1): [0004] [0005] In the formula: τ is the shear strength (MPa); F is the shear force (N); S is the shear area (mm 2 ), in this right refers to the t...

AI Technical Summary

Problems solved by technology

However, these two shear strength test methods and test devices have certain limitations. The compression shear test method is generally only suitable for relatively thick substrates. If the substrate is relatively thin, under pressure, the substrate will Bending deformation will occur, which will affect the test accuracy, and even the shear strength value cannot be measured at all, and the preparation of the test sample is more troublesome.

Therefore, when the thickness of the composite board is relatively thin (the standard stipulates that it is less than or equal to 10mm), it is necessary to use the tensile shear test method, but the tensile shear test method is only suitable for relatively thick cladding. When the cladding thickness is thinner , it is easy to neck and break at the weakest position of the cladding, which affects the test accuracy and even makes the test fail. The preparation process of the tensile-shear sample of the thin composite sheet is also difficult and cumbersome. At the same time, no matter it is a thick composite sheet It is still a thin composite sheet, and the preparation according to the national standard cannot avoid the generation of microcracks at the interface. Based on these shortcomings, many people have proposed different improvement schemes. Among them, a patent (CN 102654440 A) pointed out that the preparation of the sample into a long Strip shape, material A is clamped by one part of the mold, and material B is clamped by the other part, but this patent does not take into account that part of the sample may be bent or compressed during the shearing process or the sample may be loosened, resulting in inaccurate measurement. At the same time, because the fixed thread of the die is in the middle of the punch, the length of the sample is limited. Therefore, it is necessary to develop a method that is not only suitable for thinner composite panels, but also suitable for thicker composite panels. The preparation must also be convenient and efficient, avoid the influence of microcracks on the shear strength, and at the same time be able to accurately evaluate the composite quality of the laminated composite board

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