Method and device for three-point bending mechanical property test of small-sized sheet sample

Abstract

The invention relates to a method for testing the curvature physical property at three points of small sheet sample, wherein said method comprises: arranging preformed sheet sample with micro cracked surface deposit on the sample table; using force control method, to contact the compress head with the upper surface of sample; entering into testing conditions, to avoid high load at contact moment; connecting two electrodes of said sheet sample with voltage collecting system, and increasing load stepped, recording the maximum load, and detecting the voltage change at the crack moment of said micro crack, and converting the voltage and time data into the relationship between speed and time. Said device is formed by three-point curvature sample table, sample table support system, cooling system, heating system, loading system, and testing system. The invention can directly mount small sheet sample on the tester, to process three-point curvature test and process critical stress strength factor test of preformed micro cracked sample.

Description

technical field [0001] The invention belongs to a method and a device for testing the three-point bending mechanical properties of small-scale sheet-like samples, including the mechanical properties testing of sheet-like samples prepared with thin-film materials on the surface and the experimental research on high-speed cracking speed testing of prefabricated brittle materials with microcracks field. Background technique [0002] At present, in the research on the brittle-ductile transition of small-scale sheet samples of materials at home and abroad, the dislocation emission behavior at the crack tip, and the high-speed cracking behavior of prefabricated brittle materials with microcracks, the former generally adopts nanoindentation and bulk materials. In the latter study, the sample is usually fixed on a rigid elastic frame, and then the frame is loaded by a mechanical measurement system to achieve large-scale or high-speed crack cracking of bulk materials under the condit...

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Problems solved by technology

However, with the development of today's science and technology, relevant experiments on different materials, including polymer materials, single crystal materials, polycrystalline materials, thin film materials and amorphous materials, have been carried out in various fields. At the same time, it is required to avoid more external interference during the sample testing process, because the main concern in the study of crack tip and crack high-speed cracking behavior is the relationship between the material intrinsic structure and energy dissipation, although currently A lot of related work has been carried out, including the use of molecular dynamics simulation and finite element simulation to analyze the movement of the crack tip and the energy change of the crack tip, but the dynamic mechanism controlling the high-speed cracking of cracks is still not well understood. The scale, temperature effect, and control accuracy need to be further developed. However, the currently used method requires large samples, which cannot realize high-speed crack cracking research on small-scale samples. research cannot be performed

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