High cycle fatigue assessment of steel load-carrying cruciform welded joints: an overview of recent results

Song Wei,Xuesong Liu

doi:10.3221/igf-esis.46.10

Abstract

In this paper, high cycle fatigue failure behavior of Load-carrying Cruciform Welded Joints (LCWJ) is assessed using Strain Energy Density (SED) approach. Different analytical solutions are proposed and applied to illustrate the effects of LCWJ geometry under cycle tension and bending according to Finite Element (FE) calculation. The Notch Stress Intensity Factors (NSIF) according to the proposed analytical solutions are validated by comparing finite element data from several simulations in terms of LCWJ models, resulting in a good agreement. A bulk of experimental data taken from tests and the literature is assessed by the proposed solutions as the forms of SED, NSIF and peak stress. The results show that the SED-based analytical solutions for steel LCWJ are effective for high cycle fatigue failure analyses.

Highlights

A s one of the most typical connection types in shipbuilding or ocean engineering structures, the Load-carrying Cruciform Welded Joints (LCWJ) is widely used
Effective Traction Stress (ETS) and Equivalent Effective Traction Stress (EETS), which were based on structural mechanics theory, were employed to illustrate the weld toe and weld root failures as fillet weld size varies by Xing [17]
If the SED values are determined from Notch Stress Intensity Factors (NSIFs) analytical solutions, the Peak Stress Method (PSM) values can be calculated from Eqn 9

Summary

INTRODUCTION

A s one of the most typical connection types in shipbuilding or ocean engineering structures, the Load-carrying Cruciform Welded Joints (LCWJ) is widely used. Due to large numbers of complicated FE models are required to be created, it is cumbersome and time-consuming process for serving the needed results To simplify this procedure of creating models, an analytical formulation based on NSIFs is extended to calculate the fatigue life indicator of local approaches considering different joints geometry and cyclic loading modes. Qian et al [19] and Saiprasertkit et al [20] provided explicit parametric expressions for non-load-carrying fillet welded joints and LCWJ considering different loading conditions and material properties based on a fictitious notch rounding concept. These analytical researches give us some inspiration to extend corresponding functions. Such simple analytical equations allow a direct estimation of NSIF, SED and PSM values at weld toe or weld root in LCWJ by the available experimental data from fatigue tests and literature

NOTCH MECHANICS THEORY

It should be noted that the

EXPERIMENTAL VERIFICATION

Weld root Weld root

Tension p h t L

CONCLUSION