A three-dimensional elastoplastic analysis of mixed-mode KI/KII around the crack front

Luiz Fernando Nazaré Marques,Jaime Tupiassú Pinho De Castro,Luiz Fernando Martha,Marco Antonio Meggiolaro,T Palin-Luc,F Morel,A Carpinteri

doi:10.1051/matecconf/201930011002

Luiz Fernando Nazaré Marques, Jaime Tupiassú Pinho De Castro + Show 5 more

Open Access

https://doi.org/10.1051/matecconf/201930011002

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Abstract

Engineering problems that involve fatigue crack growth and fracture frequently can be studied by taking into account only mode-I features. However, many important problems that involve combined mode I and II loadings cannot be properly analyzed by a pure mode-I approach, which in particular may not be sufficient to estimate fracture toughness for practical purposes in such cases. Such mixed-mode problems involve crack orientation and/or load conditions that lead to combined local Stress Intensity Factors (SIFs) KI/KII around the crack front. Using multiaxial crack tip condition characterized by the crack inclination angle βin a mixed-mode KI/KII modified single edge tension SE(T) specimen, such mixed-mode effects on plastic zone shapes, volumes and plastic work UPL are taken into account to evaluate problems that involve fatigue and fracture.

Highlights

Elastoplastic (EP) stress/strain fields around crack tips are most important in structural integrity evaluations
Multiaxial loading conditions are considered by varying the crack inclination angle in a modified mixed-mode KI/KII single edge tension SE(T) specimen [9], see Fig. 1
A modified SE(T) specimen is considered in this study to simulate mixed mode I–II loading conditions by varying the crack angle, as depicted in Fig. 1.The specimen width is W, its height is 2L, the thickness is B, and the crack length is a

Summary

Introduction

Elastoplastic (EP) stress/strain fields around crack tips are most important in structural integrity evaluations. A pure mode-I approach may not be sufficient to estimate fracture toughness for practical purposes in such cases Such mixed-mode problems involve crack orientation and/or load conditions that lead to non-negligible combined local Stress Intensity Factors (SIFs) KI/KII around the crack front. This work describes and uses an improved methodology for evaluating 3D pz volumes around crack fronts based on 3D EP submodeling finite element (FE) techniques proposed and detailed studied elsewhere [6] Multiaxial loading conditions are considered by varying the crack inclination angle (in radians) in a modified mixed-mode KI/KII single edge tension SE(T) specimen [9], see Fig. 1

Finite Element Analysis

FE Model

Results

Conclusions