scholarly journals Stress Intensity Factor Evaluation for Large Scale Finite Element Analyses (Virtual Crack Closure-Integral Method (VCCM) for Mixed Mode/Complex Shaped Crack Using Tetrahedral Finite Element)

2007 ◽  
Vol 73 (733) ◽  
pp. 997-1004 ◽  
Author(s):  
Hiroshi OKADA ◽  
Kosuke ARAKI ◽  
Hiroshi KAWAI
Keyword(s):  
Stress Intensity Factor ◽  
Finite Element ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Integral Method ◽  
Mixed Mode ◽  
Large Scale ◽  
Finite Element Analyses ◽  
Shaped Crack ◽  
Factor Evaluation

Study on the Stress Intensity Factor for Mixed Mode Surface Crack under Three Point Bending

2008 ◽  
Vol 33-37 ◽  
pp. 85-90
Author(s):  
Wei Xie ◽  
Qi Qing Huang ◽  
Masanori Kikuchi
Keyword(s):  
Stress Intensity Factor ◽  
Finite Element ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Energy Release Rate ◽  
Crack Closure ◽  
Release Rate ◽  
Mixed Mode ◽  
Three Point Bending ◽  
Closure Method

In the virtual crack closure method (VCCM), the energy release rate is computed based on the results of finite element calculation, and the stress intensity factor (SIF) is computed from the energy release rate. In this paper, the stress intensity factor of mixed-mode surface cracks under three point bending is studied by using the three dimensional modified virtual crack closure method (MVCCM). The modified virtual crack closure method is required to open one element face area whose shape is arbitrary and finite element widths are unequal across the crack front. The effect of the distance between the location of load and crack face, crack shape and crack depth to the stress intensity factor is also discussed, along with practical results and conclusions.

Finite Element Fracture Mechanics Study of Pre-Northridge Connections

2006 ◽  
Vol 324-325 ◽  
pp. 1007-1010 ◽  
Author(s):  
Hong Bo Liu ◽  
Chang Hai Zhai ◽  
Yong Song Shao ◽  
Li Li Xie
Keyword(s):  
Stress Intensity Factor ◽  
Finite Element ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Fracture Behavior ◽  
Integral Approach ◽  
J Integral ◽  
Finite Element Analyses ◽  
Element Analysis ◽  
Weld Root

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.

Effects of Weld Geometry on Stress Intensity Factor Solutions for Laser Welds in Lap-Shear Specimens

2011 ◽  
Author(s):  
Kulthida Sripichai ◽  
Kamran Asim ◽  
Jwo Pan
Keyword(s):  
Stress Intensity Factor ◽  
Finite Element ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Analytical Solutions ◽  
Finite Element Analyses ◽  
Weld Geometry ◽  
Lap Shear ◽  
Laser Welds ◽  
Beam Bending

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.

scholarly journals Influence of Reinforcement Length on Singularity of Single-Lap Joints

2018 ◽  
Vol 2018 ◽  
pp. 1-8
Author(s):  
Yuqi Wang ◽  
Yanhui Li ◽  
Kaixuan Zhou
Keyword(s):  
Stress Intensity Factor ◽  
Finite Element ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Lap Joints ◽  
Finite Element Analyses ◽  
Singular Behavior ◽  
Singular Stress ◽  
Single Lap Joints ◽  
Singularity Point

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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