Hot spot stress and fatigue behavior of bird-beak SHS X-joints subjected to brace in-plane bending

2020 ◽  
Vol 150 ◽  
pp. 106701
Author(s):  
Bin Cheng ◽  
Fenghua Huang ◽  
Chen Li ◽  
Yinghao Duan ◽  
Xiao-Ling Zhao
Keyword(s):  
Hot Spot ◽  
Fatigue Behavior ◽  
Hot Spot Stress ◽  
Bird Beak ◽  
Plane Bending

Numerical Investigation on the Fatigue Behavior of the Multi-Planar Tubular DX-Joint under Combined Loads

2014 ◽  
Vol 1006-1007 ◽  
pp. 11-17
Author(s):  
Gui Jie Liu ◽  
Yu Zhang ◽  
Basit Farooq
Keyword(s):  
Finite Element ◽  
Hot Spot ◽  
Fatigue Behavior ◽  
Combined Loading ◽  
Element Analysis ◽  
Hot Spot Stress ◽  
Bending Load ◽  
Weld Toe ◽  
Plane Bending ◽  
Stress Concentration Factors

The stress concentration factors (SCFs) is used in the fatigue design for calculating hot-spot stress. However a major issue can be noted that the majority of research results are focused on the SCF distribution of uni-planar tubular joints subjected to the single basic load. By aiming to find the solution of this problem, the distribution of SCFs at the weld toe of a multi-planar tubular DX-joint which is subjected to the two set of the balanced combined loading components at the end of in-plane braces is studied by the finite element method. Thus it is concluded that for the axial plus in-plane bending load case, hot-spot stress location varies between saddle and crown position; while the location is invariably at the saddle position under combined axial plus out-of-plane bending loads. At last the API RP2A equation for predicting hot-spot stress is used for comparison with the finite element analysis results. Meanwhile the distribution of SCFs is also provided, that information indicates the-hot spot location along the weld toe affects the crack initiation.

A Comparative Study on the Fatigue Evaluation for Weldments under Out-of Plane Bending Load Using Structural Stress and Hot Spot Stress

2006 ◽  
Vol 326-328 ◽  
pp. 995-998
Author(s):  
Myung Hyun Kim ◽  
Chung In Ha ◽  
Sung Won Kang ◽  
Jeong Hwan Kim ◽  
Jae Myung Lee
Keyword(s):  
Fatigue Strength ◽  
Hot Spot ◽  
Mesh Size ◽  
Structural Stress ◽  
Hot Spot Stress ◽  
Strength Assessment ◽  
Bending Load ◽  
Load Carrying ◽  
Out Of Plane ◽  
Plane Bending

Fatigue strength assessments with two types of load carrying fillet weldment under out-of-plane bending load have been carried out by using both hot spot stress and structural stress methods. Basis for the derivation of structural stress method is discussed in detail. Finite element analyses using shell elements models have been performed for the fatigue strength assessment of weldments. As a result of the fatigue strength evaluation for load carrying transverse fillet weldment, hot spot stress method is found to be consistent with structural stress method as well as measurement. Hot spot stress, however, estimated for the load carrying longitudinal fillet weldment exhibit large variation with respect to mesh size and element type while the calculated structural stress for the longitudinal fillet weldment is relatively independent of mesh size. The fatigue life estimation according to structural stress has been introduced with the master S-N curve.

Low Cycle Fatigue of T-Tubular Joints With In-Plane Bending Loading

2005 ◽  
Author(s):  
Jo̸rn Waalen ◽  
Stig Berge
Keyword(s):  
Low Cycle Fatigue ◽  
Hot Spot ◽  
Fatigue Loading ◽  
Hot Spot Stress ◽  
Tubular Joints ◽  
Fatigue Design ◽  
R Ratio ◽  
Plane Bending ◽  
Number Of Cycles ◽  
Bending Loading

Tubular T-joints were fatigue tested with in-plane bending loading. Six models were tested, three models with R-ratio of 0 and three with R = −1. Hot spot stress was measured for the brace and for the chord using the ECSC linear extrapolation procedure. Fatigue loading was applied in load control, to obtain through thickness cracking at a number of cycles in the range 3 000–64 000 cycles. The data were analysed and compared with the current fatigue design criteria for tubular joints.

Hot spot stress parametric equations for three-planar tubular Y-joints subject to in-plane bending moment

2020 ◽  
Vol 149 ◽  
pp. 106648 ◽  
Author(s):  
Shiliu Bao ◽  
Wenhua Wang ◽  
Y.H. Chai ◽  
Xin Li
Keyword(s):  
Hot Spot ◽  
Bending Moment ◽  
Hot Spot Stress ◽  
Plane Bending

Hot-spot stress caused by out-of-plane bending moments of three-planar tubular Y-joints

2020 ◽  
Vol 100 ◽  
pp. 102179
Author(s):  
Shiliu Bao ◽  
Wenhua Wang ◽  
Xin Li ◽  
Haisheng Zhao
Keyword(s):  
Hot Spot ◽  
Bending Moments ◽  
Hot Spot Stress ◽  
Out Of Plane ◽  
Plane Bending

scholarly journals SIZE EFFECT OF WELDED THIN-WALLED TUBULAR JOINTS

2007 ◽  
Vol 07 (01) ◽  
pp. 101-127 ◽  
Author(s):  
FIDELIS RUTENDO MASHIRI ◽  
XIAO-LING ZHAO ◽  
MANFRED A. HIRT ◽  
ALAIN NUSSBAUMER
Keyword(s):  
Size Effect ◽  
Wall Thickness ◽  
Hot Spot ◽  
Fatigue Behavior ◽  
T Joints ◽  
Hot Spot Stress ◽  
Tubular Joints ◽  
Thin Walled Tube ◽  
Simple Extrapolation ◽  
Thin Walled

This paper clarifies the terminologies used to describe the size effect on fatigue behavior of welded joints. It summarizes the existing research on size effect in the perspective of newly defined terminologies. It identifies knowledge gaps in designing tubular joints using the hot spot stress method, i.e. thin-walled tubular joints with wall thickness less than 4 mm and thick-walled tubular joints with wall thickness larger than 50 mm, or diameter to thickness ratio less than 24. It is the thin-walled tubular joints that are addressed in this paper. It is found that thin-walled tube-plate T-joints do not follow the conventional trend: the thinner the section is, the higher the fatigue life. It is also found that simple extrapolation of existing fatigue design curves may result in unsafe design of thin-walled tube–tube T-joints. The effect of chord stiffness on fatigue behavior of thin-walled tubular T-joints is also discussed.

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