Failure analysis of railway draw-hook coupler was carried out.The nondestructive testing method was undertaken on some failed couplers in service to designate critical areas of a coupler.Draw-Hook coupler is used to c...Failure analysis of railway draw-hook coupler was carried out.The nondestructive testing method was undertaken on some failed couplers in service to designate critical areas of a coupler.Draw-Hook coupler is used to connect with the same hook coupler or automatic coupler.The influence of each connection types on the coupler strength in this study was discussed.A numerical stress analysis using FEM was performed,and many approaches including critical plane approach were carried out on fatigue life prediction of coupler under different conditions.The results of the proposed fatigue criterion and fatigue life predictions,as well as static numerical analysis,are validated with experimental results.展开更多
Shape optimization of mechanical components is one of the issues that have been considered in recent years. Different methods were presented such as adaptive biological for reducing costs and increasing accuracy. The ...Shape optimization of mechanical components is one of the issues that have been considered in recent years. Different methods were presented such as adaptive biological for reducing costs and increasing accuracy. The effects of step factor, the number of control points and the definition way of control points coordinates in convergence rate were studied. A code was written using ANSYS Parametric Design Language (APDL) which receives the studied parameters as input and obtains the optimum shape for the components. The results show that for achieving successful optimization, step factor should be in a specific range. It is found that the use of any coordinate system in defining control points coordinates and selection of any direction for stimulus vector of algorithm will also result in optimum shape. Furthermore, by increasing the number of control points, some non-uniformities are created in the studied boundary. Achieving acceptable accuracy seems impossible due to the creation of saw form at the studied boundary which is called "saw position".展开更多
Increasing the trains’ speed has always been one of the goals of any railway industry and train manufacturers. Also, the influence of the train speed on bogie’s dynamics has an immense importance. Therefore, it is i...Increasing the trains’ speed has always been one of the goals of any railway industry and train manufacturers. Also, the influence of the train speed on bogie’s dynamics has an immense importance. Therefore, it is important to analyze the effect of train speed on the stress distribution in different parts of train structure. In this study the result of the increasing speed on the applied stresses of a biaxial bogie frame has been examined. For this purpose, a biaxial bogie frame has been modeled using finite element analysis. Static and dynamic forces applied on the bogie with biaxial frame have been obtained for different speeds and rail roughness. The Von Mises stresses are adopted as equivalent stresses in the strength calculation. The results show that maximum stress always has been induced in the bogie bowl also the increase in bogie’s speed has remarkable effect on the increment of applied stresses in the bogie frame.展开更多
文摘Failure analysis of railway draw-hook coupler was carried out.The nondestructive testing method was undertaken on some failed couplers in service to designate critical areas of a coupler.Draw-Hook coupler is used to connect with the same hook coupler or automatic coupler.The influence of each connection types on the coupler strength in this study was discussed.A numerical stress analysis using FEM was performed,and many approaches including critical plane approach were carried out on fatigue life prediction of coupler under different conditions.The results of the proposed fatigue criterion and fatigue life predictions,as well as static numerical analysis,are validated with experimental results.
文摘Shape optimization of mechanical components is one of the issues that have been considered in recent years. Different methods were presented such as adaptive biological for reducing costs and increasing accuracy. The effects of step factor, the number of control points and the definition way of control points coordinates in convergence rate were studied. A code was written using ANSYS Parametric Design Language (APDL) which receives the studied parameters as input and obtains the optimum shape for the components. The results show that for achieving successful optimization, step factor should be in a specific range. It is found that the use of any coordinate system in defining control points coordinates and selection of any direction for stimulus vector of algorithm will also result in optimum shape. Furthermore, by increasing the number of control points, some non-uniformities are created in the studied boundary. Achieving acceptable accuracy seems impossible due to the creation of saw form at the studied boundary which is called "saw position".
文摘Increasing the trains’ speed has always been one of the goals of any railway industry and train manufacturers. Also, the influence of the train speed on bogie’s dynamics has an immense importance. Therefore, it is important to analyze the effect of train speed on the stress distribution in different parts of train structure. In this study the result of the increasing speed on the applied stresses of a biaxial bogie frame has been examined. For this purpose, a biaxial bogie frame has been modeled using finite element analysis. Static and dynamic forces applied on the bogie with biaxial frame have been obtained for different speeds and rail roughness. The Von Mises stresses are adopted as equivalent stresses in the strength calculation. The results show that maximum stress always has been induced in the bogie bowl also the increase in bogie’s speed has remarkable effect on the increment of applied stresses in the bogie frame.
