Finite Element Calculation about Stress Concentration Coefficient of Welded Butt Joints Based on the ABAQUS

2011 ◽  
Vol 80-81 ◽  
pp. 807-811 ◽  
Author(s):  
Bo Lin He ◽  
Xiao Dong Zhang

Stress concentration coefficient of welded joints has a crucial influence on mechanical properties of welded structures. Geometrical parameters of welded joints seriously affect the stress concentration coefficient. In order to increase the mechanical properties and using safety of welded structures, it has great significance for reducing stress concentration coefficient and improving the mechanical properties of welded structures by researching and improving the geometry of welded joints . In this paper, the effect of weld toe inclination angle θ and weld edge transition arc radius r on the stress concentration coefficient of welded butt joints were analyzed by using ABAQUS finite element program, and the change rule of stress concentration coefficient with the variation of the two parameters was also researched. The calculation results indicate that reducing weld toe inclination angle or increasing transition arc radius can effectively decrease the stress concentration coefficient of welded butt joints, so as to improve the mechanical properties of welded structures. For the safe use of welded structures, the true weld edge transition arc radius r should be greater than 3mm, and weld toe inclination angle θ should be smaller than 30°.

2014 ◽  
Vol 989-994 ◽  
pp. 935-938
Author(s):  
Ying Xia Yu ◽  
Bo Lin He ◽  
Xiao Dong Zhang ◽  
Si Yong Lei

Geometrical parameters of welded joint affect the stress concentration coefficient seriously. In order to increase the fatigue property of welded structure, it has great significance to reduce stress concentration coefficient of welded structures by researching and improving the geometry of welded joints. In this paper, the effects of weld toe inclination angle θ and weld edge transition arc radius r on the stress concentration coefficient of welded butt joints of magnesium alloy were analyzed by using ABAQUS finite element program, and the change rule of stress concentration coefficient with the variation of the two parameters was also researched. The calculation results indicate that reducing weld toe inclination angle or increasing transition arc radius can effectively decrease the stress concentration coefficient of welded butt joints, so as to improve the fatigue property of welded structures. For the safe use of welded structures, the true weld edge transition arc radius r should be greater than 3mm, and weld toe inclination angle θ should be smaller than 30°.


2012 ◽  
Vol 189 ◽  
pp. 350-354
Author(s):  
Ying Xia Yu ◽  
Bo Lin He ◽  
Xiao Dong Zhang

Stress concentration coefficient of welded joints has a crucial influence on mechanical properties of welded structures. Geometrical parameters of welded joints seriously affect the stress concentration coefficient. In order to increase the mechanical properties and safety of welded structures, it has great significance for reducing stress concentration coefficient and improving the mechanical properties of welded structures by researching and improving the geometry of welded joints. In this paper, the effect of stress concentration coefficient on the fatigue properties for welded cruciform joints of 16MnR steel was analyzed by using ABAQUS finite element and MSC.Fatigue programe, and the change rule of stress concentration coefficient with the variation of the parameter was studied and the fatigue life changed with the stress concentration coefficient was also researched. The calculation results indicate that reducing the weld tangent line angle θ can effectively decrease the stress concentration coefficient of welded cruciform joints, and the fatigue life of welded cruciform joints can be improved succesfully. In order to obtain the safety welded structures, the true weld tangent line angle θ should be controlled in the angle smaller than 20o.


2013 ◽  
Vol 456 ◽  
pp. 451-455
Author(s):  
Jun Yang ◽  
Bo Li ◽  
Qiang Jia ◽  
Yuan Xing Li ◽  
Ming Yue Zhang ◽  
...  

Fatigue test of the welded joint of 5083 aluminum alloy with smooth and height of specimen and the weld zone than the high test measurement and theoretical stress concentration coefficient calculation, the weld reinforcement effect of stress concentration on the fatigue performance of welded joints. The results show that: Smooth tensile strength of specimens for 264MPa, fatigue strength is 95MPa, the tensile strength of the 36%. Higher tensile strength of specimens for 320MPa, fatigue strength is 70MPa, the tensile strength of the 22%. Higher specimen stress concentration coefficient is 1.64, the stress concentration to the weld toe becomes fatigue initiation source, and reduces the fatigue strength and the fatigue life of welded joints.


2014 ◽  
Vol 989-994 ◽  
pp. 931-934 ◽  
Author(s):  
Bo Lin He ◽  
Ying Xia Yu ◽  
Xiao Dong Zhang ◽  
Song Song Xia

Geometrical parameters of welded joint affect the stress concentration coefficient seriously. In order to increase the fatigue property of welded structure, it has great significance to reduce stress concentration coefficient of welded structures by researching and improving the geometry of welded joints. In this paper, the effects of weld tangent line angle θ on the stress concentration coefficient of welded cruciform joints of magnesium alloy were analyzed by using ABAQUS finite element program, and the change rule of stress concentration coefficient with the variation of the parameter was also researched. The calculation results indicate that reducing the weld tangent line angle θ can effectively decrease the stress concentration coefficient of welded cruciform joints, so as to improve the fatigue property of welded structures. In order to have high reliability and safety of welded structures of magnesium alloy, the true weld tangent line angle θ should be controlled less than 25°.


2018 ◽  
Vol 89 (5) ◽  
pp. 782-790
Author(s):  
Shanshan He ◽  
Longdi Cheng ◽  
Wenliang Xue ◽  
Zhihong Hua ◽  
Liguo Chen ◽  
...  

This paper argues that the groove-wound licker-in racks’ spiral mounting leads teeth with an inclination angle to the rotating direction. Theoretical analysis of forces on the fibers is carried out when the inclination angle is 0 and θ: when the teeth enter the fiber layer, the inclination angle makes the pressure on fibers increases rapidly and leads to a stronger friction force on fibers. It also leads to increases in both contact area and the wrap angle of the fiber around the teeth. This article also uses ANSYS Explicit Dynamics to simulate the fiber assembly carded by a tooth, when the inclination angle is 0°, 1° and 2°. When the inclination angle of the model is 1°, its fiber deformation is 1.35 times that of 0°; its elastic strain and stress concentration coefficient are 1.40 times than that of 0°; when the inclination angle of the model is 2°, its fiber deformation is 1.72 times than that of 0°; its elastic strain and stress concentration coefficient are 2 times than that of 0°. As with the inclinations increasing, the fiber deformations increase in time grow from 0.0634 and 0.08477 to 0.10584. The simulation also shows that when the tooth works on the fibers, there is a sudden compressive stress on fibers and then this pressure transfers with time. From all of the above, the inclination angle on licker-in teeth results in larger strain and deformation on fibers, so that this inclination angle should be decreased as much as possible in practice.


2014 ◽  
Vol 633-634 ◽  
pp. 659-664 ◽  
Author(s):  
Zong Tao Fang ◽  
De Yu Tang ◽  
Yan Hua Hu ◽  
Hu Li Niu

This paper focus on fatigue problem of submarine pipelines, four points bending full scale fatigue experiment were conducted on X65 pipelines butt joints specimens, utilizing pipeline full scale fatigue test machine developed by CNPC. Meanwhile contrast test was also carried out on small specimens. The results show that the fatigue strength of full scale welded joints is lower than the small scale joints. Owing to having no regard for the influence of residual stress and size effect, the small test would provide dangerous results. The fatigue property of full scale welded joints only meets the requirement of DNV C203 W3 curve, and meets the needs of DNV C203 F3 curve basically while not meet BS 7608 F2 curve’s requirements which relatively demand higher. Weld toe and geometric discontinuous near weld root is the weak point for the whole welded joints.


Author(s):  
E.E. Deryugin ◽  

The article considers a crack in the form of a narrow cut with a certain cfn at the cut out in an unbounded plate. The characteristics of the mechanical state of this system under uniaxial loading are determined: the stress concentration coefficient, the crack-driving force, and the energy of a solid with a crack. The elastic energy expenditure during crack propagation is determined. The general regularities of the mechanical state of a solid with a crack, not necessary having the form of an ellipse, are revealed. An important parameter of a crack is the curvature at the tip. It is shown that the Griffiths crack does not actually have a singularity at the tip. The stress strain state of the plate with an elliptical crack is identical to the same of the plate with a focus of homogeneous plastic deformation.


2012 ◽  
Vol 12 (01) ◽  
pp. 179-194 ◽  
Author(s):  
TAO CHEN ◽  
QIAN-QIAN YU ◽  
XIANG-LIN GU ◽  
XIAO-LING ZHAO

This paper reports an experimental study on the use of carbon fiber-reinforced polymer (CFRP) sheets to strengthen non-load-carrying cruciform welded joints subjected to fatigue loading. Failure modes and corresponding fatigue lives were recorded during tests. Scatter of test results was observed. Thereafter, a series of numerical analyses were performed to study the effects of weld toe radius, the number of CFRP layers and Young's modulus of reinforced materials on local stress concentration at a weld toe. It was found that fatigue life of such welded connections can be enhanced because of the reduction of stress concentration caused by CFRP strengthening. Parametric study indicates that the weld toe radius and the amount of CFRP are the key parameters influencing the stress concentration factors and stress ranges of the joint. Enhancement of modulus for adhesive and CFRP sheets can also be beneficial to the fatigue performance to some extent.


2012 ◽  
Vol 28 (6) ◽  
pp. 436-440
Author(s):  
Krzysztof Kwieciński ◽  
Robert Jachym ◽  
Krzysztof Krasnowski

2010 ◽  
Vol 654-656 ◽  
pp. 2560-2563 ◽  
Author(s):  
Kalenda Mutombo ◽  
Madeleine du Toit

Semi-automatic and automatic pulsed gas metal arc welding (GMAW) of aluminium alloy 5083 with ER5356 filler wire causes considerable softening in the weld. The tensile strength of dressed automatic welds approaches that of the base metal, but the stress concentration caused by the weld toe in undressed semi-automatic welds reduced the tensile strength significantly. Fully automatic welds displayed improved fatigue properties compared to semi-automatic welds.


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