Test piece for fracture toughness of III type cracks

Abstract

The invention discloses a test piece for fracture toughness of III type cracks. The test piece is a rectangular flat-plate test piece; the length of the broad edge is more than the thickness and less than the length of the long edge; initial cracks are symmetrically arranged on the two sides in the broad edge direction of a flat plate; symmetric V-shaped edge cutting grooves are formed in the two sides in the thickness direction of the flat plate. According to the test piece, the fracture toughness of the III type cracks of a plastic material can be effectively and stably tested and a test can be finished on a universal test machine.

Description

technical field [0001] The invention belongs to the field of testing basic mechanical properties of solid mechanics, in particular to a test piece for fracture toughness of type III cracks. Background technique [0002] Material fracture toughness is a basic parameter of fracture mechanics, which is a measure of the ability of a material to prevent the expansion of macroscopic crack instability, and it is also a toughness parameter for a material to resist brittle failure. It has nothing to do with the size and shape of the crack itself and the magnitude of the applied stress. It is an inherent characteristic of the material, which is only related to the material itself, heat treatment and processing technology. is the critical value of the stress intensity factor. It is commonly used to express the energy absorbed by the object before the fracture or the work done by the outside world on the object. [0003] The basic fracture modes are Type I, Type II, and Type III. Ty...

AI Technical Summary

Problems solved by technology

Some are limited by the characteristics of the test piece and the material itself, and type I and type II fractures occur during the experiment, resulting in a low success rate of the experiment

Or the experiment requires proprietary experimental equipment, which cannot be completed on the universal testing machine

Literature "Design and analysis of a new six-point edge crack torsion (6ECT) specimen for mode III interlaminar fracture characterization" (A.B.Pereira, A.B.de Morais, M.F.S.F.de Moura, Composites Part A: Applied Science and Manufacturing, Volume42, Issue2, February2011, Pages131–139), proposed a 6-point boundary loading test for strip-shaped specimens. There are many loading points in the test, and it is not conducive to symmetrical loading. method to improve

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