Data Processing Procedure for Fatigue Life Prediction of Spot-Welded Joints Using a Structural Stress Method

2017 ◽  
pp. 198-211 ◽  
Author(s):  
Hong-Tae Kang ◽  
Xiao Wu ◽  
Abolhassan K. Khosrovaneh ◽  
Zhen Li
Keyword(s):  
Fatigue Life ◽  
Data Processing ◽  
Welded Joints ◽  
Life Prediction ◽  
Fatigue Life Prediction ◽  
Structural Stress ◽  
Processing Procedure ◽  
Data Processing Procedure ◽  
Spot Welded

scholarly journals A notch stress method for fatigue life prediction of spot-welded joints

2019 ◽  
Vol 300 ◽  
pp. 19003
Author(s):  
Changjian Wei ◽  
Hong Tae Kang
Keyword(s):  
Fatigue Life ◽  
Welded Joints ◽  
Life Prediction ◽  
Structure Design ◽  
Fatigue Life Prediction ◽  
Local Geometry ◽  
Structural Stress ◽  
Lap Shear ◽  
Notch Stress ◽  
Spot Welded

Spot-welded joints are widely used in the construction of vehicle structures and frequently become critical locations for fatigue failure. Hence, it is essential to have reliable fatigue life prediction method for the spot-welded joints during vehicle structure design. In this paper, a new notch stress approach is developed for fatigue life prediction of the spot-welded joints. Currently, structural stress methods are widely used in automotive industry for fatigue life prediction of spot-welded joints. However, these methods are not well considering local geometry information. This paper introduces a notch stress based method to overcome the limitation of the structural stress methods. In the notch stress method, stress concentration factors for spot-welded joints are calculated from stress intensity factor equations. Then, the notch stress method is validated with fatigue test results of lap-shear and coach peel specimens.

Structural Stress Correction Methods for Linear Elastic Finite Element Analysis of Spot Welded Joints

2016 ◽  
Author(s):  
Hong-Tae Kang ◽  
Xiao Wu
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Fatigue Life ◽  
Welded Joints ◽  
Life Prediction ◽  
Structural Stress ◽  
Test Results ◽  
Element Analysis ◽  
Linear Elastic ◽  
Spot Welded

Structural stress concepts are widely used in fatigue life prediction of spot welds and seam welds in vehicle structures. For fatigue life prediction of welded joints based on the structural stress methods, it is necessary to obtain applied force ranges versus fatigue life of the welded specimens. Then, the force ranges versus fatigue life information is converted to structural stress ranges versus fatigue life (S-N) of the joints. The structural stress ranges versus the fatigue life curve of the welded specimens becomes the material fatigue property of the welded joints to predict fatigue life of joints in vehicle structures. While converting the applied load ranges to the structural stress ranges, linear elastic finite element analysis (FEA) is used. Therefore, the applied load ranges are considered as the responses of linear elastic deformation even though the load ranges consist of the linear elastic deformation and plastic deformation. As results the structural stress ranges of the welded joints are reduced in S-N curve. This study introduces simple techniques for spot welded joints to include the plastic deformation effect on the structural stress calculation without performing elastic-plastic finite element analysis. Fatigue test results of spot welded joints for lap-shear and coach peel specimens of advanced high strength steels (AHSS) and mild steels were used. The corrected structural stress methods showed better correlation with the test results.

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