Test piece for fracture toughness of III type cracks

A technology of fracture toughness and test pieces, which is applied in the field of testing the basic mechanical properties of solid mechanics, can solve the problems of unfavorable symmetrical loading, low experimental success rate, and many loading points, etc., and achieve less experimental expenses, simple experiments, and easy operation and processing Effect

Inactive Publication Date: 2013-12-25
NANJING UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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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

Method used

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  • Test piece for fracture toughness of III type cracks
  • Test piece for fracture toughness of III type cracks
  • Test piece for fracture toughness of III type cracks

Examples

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Effect test

Embodiment 1

[0029] The test piece of fracture toughness of type III crack of the present invention is applied to the measurement of fracture toughness of type III crack of double-base propellant, and the test piece of fracture toughness of flat type III crack of double-base propellant is produced. In order to ensure the validity of the test, according to the description of the claims in the present invention, the test piece is 100mm long and 80mm wide. Due to the low material density and relatively high stiffness, the thickness can be taken as 8mm, and the initial crack length is taken as 10mm. Because the modulus of the double-base propellant is small and the toughness is small, the depth of the V-shaped groove is taken as 1mm. Practice has proved that the invention of the test specimen for the fracture toughness of the mode III crack can be well applied to the measurement of the fracture toughness of the mode III crack of the double-base propellant. Shear strain.

Embodiment 2

[0031] The test specimen of the mode III crack fracture toughness of the present invention is applied to the measurement of the fracture toughness of the mode III crack of No. 45 steel, and the test specimen of the flat mode III crack fracture toughness of the No. 45 steel is produced. In order to ensure the validity of the test, according to the description of the claims in the present invention, the test piece is 100mm long and 80mm wide. Due to the high density of steel, the test results are easily affected by the weight of the material, so the thickness of the test piece is 8mm, and the initial crack length is 10mm. Because the modulus and toughness of the steel are large, the depth of the V-shaped groove is 2mm. Practice has proved that the invention of the test specimen for the fracture toughness of the mode III crack can be well applied to the measurement of the fracture toughness of the mode III crack of No. 45 steel. strain.

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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...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N3/24
Inventor 胡少青陈雄鞠玉涛郑健周长省许进升王鸿丽周清春韦震
Owner NANJING UNIV OF SCI & TECH
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