Comparison of the constraint parameters in elastic-plastic fracture mechanics

Yury Matvienko

doi:10.3221/igf-esis.49.04

Abstract

To describe the effect of crack-tip constraint on the stress field for finite cracked bodies, the following most widely used constraint parameters can be employed in elastic-plastic fracture mechanics, namely, local triaxiality parameter, constraint parameter Q, the second fracture mechanics parameter A using a three-term elastic-plastic asymptotic expansion. To establish the relationship between different constraint parameters, the crack-tip stress fields are employed. Relationship between the crack-tip constraint parameters A, A2, Q and of elastic-plastic fracture mechanics is investigated.

Highlights

To describe the effect of crack-tip constraint on the stress field for finite cracked bodies, the following most widely used constraint parameters can be employed in elastic-plastic fracture mechanics, namely, local triaxiality parameter, constraint parameter Q, the second fracture mechanics parameter A using a three-term elastic-plastic asymptotic expansion
A t present time, it becomes obvious that classical one-parameter fracture mechanics based on traditional parameters, such as the stress intensity factor, the J-integral, etc., is not sufficient for describing the stress field in the vicinity of the crack tip for finite cracked bodies
To describe the effect of crack-tip constraint in elastic-plastic two-parameter fracture mechanics, the following possible constraint parameters should be introduced into basic equations and criteria of fracture mechanics in the case of small scale yielding and large scale yielding conditions, namely, local triaxiality parameter [1], constraint parameter Q [2, 3], the second fracture mechanics parameter A of a three-term elastic-plastic asymptotic expansion [4,5,6]

Summary

Introduction

A t present time, it becomes obvious that classical one-parameter fracture mechanics based on traditional parameters, such as the stress intensity factor, the J-integral, etc., is not sufficient for describing the stress field in the vicinity of the crack tip for finite cracked bodies. To describe the effect of crack-tip constraint on the stress field for finite cracked bodies, the following most widely used constraint parameters can be employed in elastic-plastic fracture mechanics, namely, local triaxiality parameter, constraint parameter Q, the second fracture mechanics parameter A using a three-term elastic-plastic asymptotic expansion. To establish the relationship between different constraint parameters, the crack-tip stress fields are employed.

Results

Conclusion