Path‐dependent multiaxial fatigue prediction of welded joints using structural strain method

2021 ◽  
Author(s):  
Qinghua Han ◽  
Peipeng Wang ◽  
Yan Lu
Keyword(s):  
Welded Joints ◽  
Multiaxial Fatigue ◽  
Path Dependent ◽  
Structural Strain ◽  
Strain Method

A Comprehensive Structural Strain Method Incorporating Strain-Hardening Effects: From LCF to Ratcheting Evaluations

2018 ◽  
Author(s):  
Xianjun Pei ◽  
Pingsha Dong ◽  
Shaopin Song ◽  
David Osage
Keyword(s):  
Low Cycle Fatigue ◽  
Numerical Algorithms ◽  
Complex Stress ◽  
Structural Effect ◽  
Complex Stress State ◽  
Material Nonlinearity ◽  
Strain Behavior ◽  
Nonlinear Stress ◽  
Structural Strain ◽  
Strain Method

As a further extension to the structural strain method first introduced by Dong et al [1], this paper presents an enhanced structural strain method which incorporates material nonlinearity and for two typical weld structures, i.e. weldment with plate sections (e.g. gusset weld or cruciform weld etc.) and weldment with beam sections. (e.g. pipe structures). A modified Ramberg-Osgood is introduced to capture nonlinear stress strain behavior of the material. A set of numerical algorithms is used to deal with complex stress state induced by structural effect such as beam section and plane strain condition. The proposed structural strain method is then applied to analysis of fatigue data of weldment made from different materials including steel, aluminum and titanium. It is shown that the enhanced structural strain method provides a unified way to correlate fatigue life of weldment in both high cycle and low cycle fatigue regime. The method is also used to study ratcheting problem raised up by Bree. A modified Bree diagram is given by considering material nonlinearity.

scholarly journals Extremely-Low-Cycle Fatigue Damage for Beam-to-Column Welded Joints Using Structural Details

Materials ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1768
Author(s):  
Lizhen Huang ◽  
Weilian Qu ◽  
Ernian Zhao
Keyword(s):  
Fatigue Damage ◽  
Welded Joints ◽  
Low Cycle Fatigue ◽  
Damage Model ◽  
Multiaxial Fatigue ◽  
Fatigue Properties ◽  
Cycle Fatigue ◽  
Butt Weld ◽  
Damage Models ◽  
Structural Details

The multiaxial fatigue critical plane method can be used to evaluate the extremely-low-cycle fatigue (ELCF) damage of beam-to-column welded joints in steel frameworks subjected to strong seismic activity. In this paper, fatigue damage models using structural detail parameters are studied. Firstly, the fatigue properties obtained from experiments are adopted to assess ELCF life for steel frameworks. In these experiments, two types of welded specimens, namely, plate butt weld (PB) and cruciform load-carrying groove weld (CLG), are designed according to the structural details of steel beam and box column joints, in which both structural details and welded factors are taken into account. Secondly, experiments are performed on three full-scale steel welded beam-to-column joints to determine the contribution of stress and/or strain to damage parameters. Finally, we introduce a modification of the most popular fatigue damage model of Fatemi and Socie (FS), modified by us in a previous study, for damage evaluation, and compare this with Shang and Wang (SW) in order to examine the applicability of the fatigue properties of PB and CLG. This study shows that the modified FS model using the fatigue properties of CLG can predict the crack initiation life and evaluate the damage of beam-to-column welded joints, and can be subsequently used for further investigation of the damage evolution law.

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