Finite Element Analyses of Stress Intensity Factor Solutions for Discontinuous Gas Metal Arc Welds under Lap-Shear Loading Conditions

2017 ◽  
Vol 10 (2) ◽  
pp. 160-166
Author(s):  
Catherine Amodeo ◽  
Jwo Pan
Author(s):  
Kulthida Sripichai ◽  
Kamran Asim ◽  
Jwo Pan

In this paper, the effects of weld geometry on the stress intensity factor solutions for laser welds in lap-shear specimens are investigated. Analytical stress intensity factor solutions for laser welded lap-shear specimens based on the beam bending theory are derived and compared with the analytical solutions for two semi-infinite solids with connection. Finite element analyses of laser welded lap-shear specimens with different weld widths were also conducted to obtain the stress intensity factor solutions. Approximate closed-form stress intensity factor solutions based on the results of the finite element analyses in combination with the analytical solutions based on the beam bending theory and Westergaard stress function for a full range of the normalized weld widths are developed for use with the stress intensity factor solutions for kinked cracks to correlate and estimate fatigue lives of laser welded lap-shear specimens. The effects of the weld protrusion on the stress intensity factor solutions for the pre-existing cracks in lap-shear specimens are also investigated. The presence of the weld protrusion decreases the stress intensity factor solutions for the pre-existing crack near the weld protrusion for the load carrying sheets and the lower stress intensity factor solutions can be used to explain more favorable conditions for kinked fatigue crack propagation from the other pre-existing crack tip and to estimate fatigue lives of laser welded lap-shear specimens under high cycle loading conditions as observed in experiments.


2006 ◽  
Vol 324-325 ◽  
pp. 1007-1010 ◽  
Author(s):  
Hong Bo Liu ◽  
Chang Hai Zhai ◽  
Yong Song Shao ◽  
Li Li Xie

The objective was to quantify the variation of stress intensity factor to weld root flaw sizes in steel frame connections. Finite-element analyses were used to study fracture toughness in welded beam-column connections. Investigations of fracture behavior mainly focused on the standard pre-Northridge connection geometry. Finite element analysis was performed using the ANSYS computer program. Stress intensity factor was calculated through a J-integral approach. Results show that stress intensity factor is not uniform and is largest in the middle of beam flange. Stress intensity factor increases nearly linear with the increase of flaw size. Backing bars have little effect on weld fractures.


1977 ◽  
Vol 99 (4) ◽  
pp. 324-328 ◽  
Author(s):  
Y. Urabe ◽  
A. S. Kobayashi ◽  
A. F. Emery ◽  
W. J. Love

A dynamic finite element code was used to compute the dynamic stress intensity factors and crack arrest stress intensity factor which are related to the crack run-arrest response in a tapered double cantilever beam (DCB) specimen machined from A533B steel. Measured crack velocities of a fracturing tapered DCB specimen were used to prescribe a crack motion under both fixed grip and variable loading conditions at the two loading pins. Numerically and experimentally determined dynamic strains were compared at three locations on the fracturing tapered DCB specimen. This comparative study showed that the fixed grip condition modeled the actual dynamic state well and that the crack arrest stress intensity factor, KIa, computed on the bases of fixed grip and variable loading conditions differed by a factor of approximately 0.6.


2018 ◽  
Vol 2018 ◽  
pp. 1-8
Author(s):  
Yuqi Wang ◽  
Yanhui Li ◽  
Kaixuan Zhou

In order to enhance the strength of single-lap joints, the single-lap joints with reinforcements were proposed. The influence of reinforcement length on the singular behavior near to the interface point of single-lap joints was investigated theoretically and numerically. The theoretical strength of singularity point was calculated by Bogy determinant. Stresses along the interface close to the singularity points were calculated with finite element analyses (FEAs). Results showed that the singular stress intensity factor of single-lap joints can be decreased by the reinforcement. However, the singular stress intensity factor of single-lap joints with reinforcements was decreased slightly with increasing reinforcement length.


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