In order to obtain the strength design equations for internally ring-stiffened circular hollowsection tubular DT（ double tee）-joints subjected to brace axial compression or tension, theoretical and numerical studies...In order to obtain the strength design equations for internally ring-stiffened circular hollowsection tubular DT（ double tee）-joints subjected to brace axial compression or tension, theoretical and numerical studies on 800 stiffened joints were conducted. Based on the failure mechanism of the stiffened joints, four theoretical models and corresponding equations for predicting the strength of the stiffeners are proposed. Combined with existing unstiffened DT-joint design equations, a design equation for the stiffened joints is proposed. The finite element analysis shows that the failure of the stiffened joints under brace axial loads can be characterized by plastic hinges forming in the stiffener and chord wall yielding in the vicinity of the brace-chord intersection. The reliability of the proposed stiffener strength equations is demonstrated by a reliability analysis. Good agreement is achieved between the stiffened joint strength calculated from the proposed joint strength equation and that obtained from finite element analysis.展开更多
The fatigue life evaluation of the girth butt weld within the welded cast steel joint was studied based on the extrapolation notch stress method.Firstly,the mesh sensitivity of the finite element model of the welded c...The fatigue life evaluation of the girth butt weld within the welded cast steel joint was studied based on the extrapolation notch stress method.Firstly,the mesh sensitivity of the finite element model of the welded cast steel joint was analyzed to determine the optimal mesh size.Based on the stress field analysis of the finite element model of the welded cast steel joint at the weld toe and weld root,the sharp model of the extrapolation notch stress method was applied to derive the effective notch stress of the rounded model belonging to the effective notch stress method,in which the key problem is to calculate the extrapolation point C,and the extrapolation point C has an exponential function relationship with the geometric parameters of the welded cast steel joint.By setting different values of geometric parameters,the corresponding value of parameter C is calculated,and then the functional relationship between the extrapolation point C and the geometric parameters can be obtained by the multiple linear regression analysis.Meanwhile,the fatigue life evaluation of the girth butt weld within welded cast steel joints based on the effective notch stress was performed according to the guideline recommended by the IIW(International Institute of Welding).The results indicate that the extrapolation notch stress method can effectively simplify the process of calculating the effective notch stress and accurately evaluate the fatigue life of the girth butt weld within welded cast steel joints.展开更多
基金The Open Project of State Key Laboratory of Subtropical Building Science,South China University of Technology(No.2014KB29,2015ZB30)
文摘In order to obtain the strength design equations for internally ring-stiffened circular hollowsection tubular DT（ double tee）-joints subjected to brace axial compression or tension, theoretical and numerical studies on 800 stiffened joints were conducted. Based on the failure mechanism of the stiffened joints, four theoretical models and corresponding equations for predicting the strength of the stiffeners are proposed. Combined with existing unstiffened DT-joint design equations, a design equation for the stiffened joints is proposed. The finite element analysis shows that the failure of the stiffened joints under brace axial loads can be characterized by plastic hinges forming in the stiffener and chord wall yielding in the vicinity of the brace-chord intersection. The reliability of the proposed stiffener strength equations is demonstrated by a reliability analysis. Good agreement is achieved between the stiffened joint strength calculated from the proposed joint strength equation and that obtained from finite element analysis.
基金The National Key Research and Development Program of China(No.2017YFC0805100),the National Natural Science Foundation of China(No.51578137)the Priority Academic Program Development of Jiangsu Higher Education Institutions,the Open Research Fund Program of Jiangsu Key Laboratory of Engineering Mechanics.
文摘The fatigue life evaluation of the girth butt weld within the welded cast steel joint was studied based on the extrapolation notch stress method.Firstly,the mesh sensitivity of the finite element model of the welded cast steel joint was analyzed to determine the optimal mesh size.Based on the stress field analysis of the finite element model of the welded cast steel joint at the weld toe and weld root,the sharp model of the extrapolation notch stress method was applied to derive the effective notch stress of the rounded model belonging to the effective notch stress method,in which the key problem is to calculate the extrapolation point C,and the extrapolation point C has an exponential function relationship with the geometric parameters of the welded cast steel joint.By setting different values of geometric parameters,the corresponding value of parameter C is calculated,and then the functional relationship between the extrapolation point C and the geometric parameters can be obtained by the multiple linear regression analysis.Meanwhile,the fatigue life evaluation of the girth butt weld within welded cast steel joints based on the effective notch stress was performed according to the guideline recommended by the IIW(International Institute of Welding).The results indicate that the extrapolation notch stress method can effectively simplify the process of calculating the effective notch stress and accurately evaluate the fatigue life of the girth butt weld within welded cast steel joints.
