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.

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.

Prediction of the critical stress intensity factor of single-lap adhesive joints using a coupled ratio method and an analytical model

2018 ◽  
Vol 233 (7) ◽  
pp. 1393-1403 ◽  
Author(s):  
S Rastegar ◽  
MR Ayatollahi ◽  
A Akhavan-Safar ◽  
LFM da Silva
Keyword(s):  
Stress Intensity Factor ◽  
Shear Stress ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Critical Stress ◽  
Critical Stress Intensity Factor ◽  
Lap Joints ◽  
Factor H ◽  
Ratio Method ◽  
Single Lap Joints

The ratio method coupled with the analytical Volkersen model is proposed for the prediction of critical stress intensity factor ( H c) in adhesively bonded single-lap joints. Based on the ratio method, it was shown that despite the singularity of the stress intensity factor ( H) near the bonding end, the ratio of H ( H c) for two single-lap joints with different substrate thicknesses is almost equal at singular and nonsingular regions. It was also found that for joints with different substrate thicknesses, the ratio of H based on the interface shear stress obtained by finite element method is almost equal to the ratio of H obtained using the Volkersen model based on the shear stress along the adhesive mid-plane. The proposed method was applied on single-lap joints with different substrate thicknesses and bonding lengths. According to the experimental results, it was shown that, despite the considerable errors which exist in the stress prediction using the Volkersen model, a combination of Volkersen model and the ratio method could predict the H c of the tested single-lap joints very well. Also using the obtained H c, failure loads of the tested joints were predicted. A good correlation was found between the experimental data and the theoretical predictions.

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.

Application of Extended Finite Element Method (XFEM) to Stress Intensity Factor Calculations

2015 ◽  
Author(s):  
Do-Jun Shim ◽  
Mohammed Uddin ◽  
Sureshkumar Kalyanam ◽  
Frederick Brust ◽  
Bruce Young
Keyword(s):  
Finite Element Method ◽  
Stress Intensity Factor ◽  
Finite Element ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Degrees Of Freedom ◽  
Extended Finite Element Method ◽  
Partition Of Unity ◽  
Extended Finite Element ◽  
Element Method

The extended finite element method (XFEM) is an extension of the conventional finite element method based on the concept of partition of unity. In this method, the presence of a crack is ensured by the special enriched functions in conjunction with additional degrees of freedom. This approach also removes the requirement for explicitly defining the crack front or specifying the virtual crack extension direction when evaluating the contour integral. In this paper, stress intensity factors (SIF) for various crack types in plates and pipes were calculated using the XFEM embedded in ABAQUS. These results were compared against handbook solutions, results from conventional finite element method, and results obtained from finite element alternating method (FEAM). Based on these results, applicability of the ABAQUS XFEM to stress intensity factor calculations was investigated. Discussions are provided on the advantages and limitations of the XFEM.

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