In order to improve the strength and stiffness of shield cutterhead, the method of fuzzy mathematics theory in combination with the finite element analysis is adopted. An optimal design model of structural parameters ...In order to improve the strength and stiffness of shield cutterhead, the method of fuzzy mathematics theory in combination with the finite element analysis is adopted. An optimal design model of structural parameters for shield cutterhead is formulated,based on the complex engineering technical requirements. In the model, as the objective function of the model is a composite function of the strength and stiffness, the response surface method is applied to formulate the approximate function of objective function in order to reduce the solution scale of optimal problem. A multi-objective genetic algorithm is used to solve the cutterhead structure design problem and the change rule of the stress-strain with various structural parameters as well as their optimal values were researched under specific geological conditions. The results show that compared with original cutterhead structure scheme, the obtained optimal scheme of the cutterhead structure can greatly improve the strength and stiffness of the cutterhead, which can be seen from the reduction of its maximum equivalent stress by 21.2%, that of its maximum deformation by 0.75%, and that of its mass by 1.04%.展开更多
The fishtail in head and tail of the slabs was studied during V-H hot rolling process. With the application of ANSYS/LS-DYNA, simulation analysis was used to research this process. The various factors which have a gre...The fishtail in head and tail of the slabs was studied during V-H hot rolling process. With the application of ANSYS/LS-DYNA, simulation analysis was used to research this process. The various factors which have a great influence on fishtail shapes were analysed, such as initial width, initial thickness, radius of the edger roll and horizontal roll, edging draught,horizontal reduction rate, and friction coefficient of the surface. Then the curves that can describe the shapes were obtained. After a certain time of self-learning, the optimized curves were given out. At last, through the fitting of the simulation test results, the math models for the area of fishtail defect changing with the presented factors were received. The experimental results show that the accuracy of the prediction for the fishtail shapes is more than 95%. With the application of the prediction for the fishtail shapes and the area of the fishtail defect, the loss rate of the slab is decreased by about 0.1%.展开更多
This paper presents a methodology for analytical calculation and computational simulation using the finite element method for piezoresistive graphite sensor element on flexible polymer substrate,A4 paper.The computer ...This paper presents a methodology for analytical calculation and computational simulation using the finite element method for piezoresistive graphite sensor element on flexible polymer substrate,A4 paper.The computer simulation aims to find the region of greatest mechanical tension and deflection of the circular diaphragm set in the circumference edges.The steps for simulation are geometry definition,mesh generation,inclusion of material physical properties and simulation execution.The mathematical modeling of maximum mechanical stress and deflection is described analytically and computationally.The analytical calculations were compared with the computer simulation and presented a relative percentage error of 3.38%for the maximum deflection.The results show that the piezoresistor should be positioned at the edges of the circular diaphragm to take advantage of maximum mechanical stress by defining the best location for graphite film deposition for sensor device designs and fabrications.展开更多
基金Project(51074180) supported by the National Natural Science Foundation of ChinaProject(2012AA041801) supported by the National High Technology Research and Development Program of China+2 种基金Project(2007CB714002) supported by the National Basic Research Program of ChinaProject(2013GK3003) supported by the Technology Support Plan of Hunan Province,ChinaProject(2010FJ1002) supported by Hunan Science and Technology Major Program,China
文摘In order to improve the strength and stiffness of shield cutterhead, the method of fuzzy mathematics theory in combination with the finite element analysis is adopted. An optimal design model of structural parameters for shield cutterhead is formulated,based on the complex engineering technical requirements. In the model, as the objective function of the model is a composite function of the strength and stiffness, the response surface method is applied to formulate the approximate function of objective function in order to reduce the solution scale of optimal problem. A multi-objective genetic algorithm is used to solve the cutterhead structure design problem and the change rule of the stress-strain with various structural parameters as well as their optimal values were researched under specific geological conditions. The results show that compared with original cutterhead structure scheme, the obtained optimal scheme of the cutterhead structure can greatly improve the strength and stiffness of the cutterhead, which can be seen from the reduction of its maximum equivalent stress by 21.2%, that of its maximum deformation by 0.75%, and that of its mass by 1.04%.
基金Project(N100307002)supported by the Fundamental Research Funds for the Central Universities,ChinaProject(61174115)supported by the National Natural Science Foundation of China
文摘The fishtail in head and tail of the slabs was studied during V-H hot rolling process. With the application of ANSYS/LS-DYNA, simulation analysis was used to research this process. The various factors which have a great influence on fishtail shapes were analysed, such as initial width, initial thickness, radius of the edger roll and horizontal roll, edging draught,horizontal reduction rate, and friction coefficient of the surface. Then the curves that can describe the shapes were obtained. After a certain time of self-learning, the optimized curves were given out. At last, through the fitting of the simulation test results, the math models for the area of fishtail defect changing with the presented factors were received. The experimental results show that the accuracy of the prediction for the fishtail shapes is more than 95%. With the application of the prediction for the fishtail shapes and the area of the fishtail defect, the loss rate of the slab is decreased by about 0.1%.
文摘This paper presents a methodology for analytical calculation and computational simulation using the finite element method for piezoresistive graphite sensor element on flexible polymer substrate,A4 paper.The computer simulation aims to find the region of greatest mechanical tension and deflection of the circular diaphragm set in the circumference edges.The steps for simulation are geometry definition,mesh generation,inclusion of material physical properties and simulation execution.The mathematical modeling of maximum mechanical stress and deflection is described analytically and computationally.The analytical calculations were compared with the computer simulation and presented a relative percentage error of 3.38%for the maximum deflection.The results show that the piezoresistor should be positioned at the edges of the circular diaphragm to take advantage of maximum mechanical stress by defining the best location for graphite film deposition for sensor device designs and fabrications.
