Effect of Yield Strength Distribution Welded Joint on Crack Propagation Path and Crack Mechanical Tip Field.

Yueqi Bi,Jishuang Lv,Rehmat Bashir,Shuai Wang,Xiaoming Yuan,He Xue

doi:10.3390/ma14174947

Abstract

Due to the particularity of welding processes, the mechanical properties of welded joint materials, especially the yield strength, are unevenly distributed, and there are also a large number of micro cracks, which seriously affects the safety performance of welded joints. In this study, to analyze the effect of the uneven distribution of yield strength on the crack propagation path of welded joints, other mechanical properties and residual stresses of welded joints are ignored. In the ABAQUS 6.14 finite element software, the user-defined field (USDFLD) subroutine is used to define the unevenly distributed yield strength, and extended finite element (XFEM) is used to simulate crack propagation. In addition, the static crack finite element model of the welded joint model is established according to the crack propagation path, which is given the static crack model constant stress intensity factor load, and the influence of an uneven yield strength distribution on mechanical field is analyzed. The results show that the crack length of welded joints as well as the plastic deformation range of the crack tip in high stress areas can be reduced with the increase of yield strength along the crack propagation direction. Moreover, the crack deflects to the low yield strength side. This study provides an analytical reference for the crack path prediction of welded joints.

Highlights

Material properties have a vital role for the selection of material and the life of a component
To express the mechanical heterogeneity of the welded joint is of great significance for calculating and predicting the crack propagation direction and the stress and strain field at the crack tip, considering the safety evaluation of the welded joint
Fan et al [10,11,12] used this method to evaluate the safety of welded joints, established a finite element model of welded joints with dual material sandwich structure, and analyzed the effects of work hardening, initial crack location, and yield strength mismatch on fracture toughness and the crack propagation path

Summary

Introduction

Material properties have a vital role for the selection of material and the life of a component. Fan et al [10,11,12] used this method to evaluate the safety of welded joints, established a finite element model of welded joints with dual material sandwich structure, and analyzed the effects of work hardening, initial crack location, and yield strength mismatch on fracture toughness and the crack propagation path. Zhao et al [15,16] added a heat affected zone when establishing the finite element model of a sandwich structure-welded joint, analyzed the differences of a stress corrosion cracking mechanical field in a heat affected zone under constant load and constant stress intensity factor load, and discussed the influence of yield strength mismatch on a driving force for crack growth. The stress–strain field of the finite element model of the welded joint was discontinuous at the material interface, which seriously affected the accuracy of the safety evaluation of the welded joint

Methods

Results

Conclusion