Theoretics Study And Design Method Of Fiber Enlaced Composite Materials Shell

The development of mechanical design and theory has a close connection with the invention and application of new materials, and the research about application of new materials and theory. The research work of this article is a part of the "reliability research of cylinders for compressed natural gas vehicles" project which was subsidized by ChongQing Scientific Committee, it aims to research the destructive theory and design theory and method for Fiber Enlaced Composite Materials shell, and synthetically use finite element optimal technology to set up composite materials CAD system. .Firstly, the interlaminar stresses of composite materials shell is analyzed, and the destructive influence of the actual structure of composite materials of distribution of composite materials shell's interlaminar stresses is raised in this paper. Fiber Enlaced Composite Materials is widely used in engineering project. The mechanics property of the shell is rather complicated when analyzing the affect of composite materials shell's interlaminar stresses. The result shows that the interlaminar stresses of composite materials shell will be changed much according to the change of the fiber direction, not only the distribution style, but also the Interface which the maxinal interlaminar shearing stresses belongs to.Secondly, the finite element analysis of composite materials interlaminar stresses is researched in this paper. The interlaminar stresses slightly influenced by the composite materials'lamella curvature, but not influenced by the distributing form of interlaminar stresses follow thickness are found. This paper also offers the methematics analyzing method of how to calculate interlaminar stressesaccording to the finite element analyzing method, it helps to do deeper research on composite materials shells. Composite materials shell's finite element analysis cites 3-D nonlinear finite element analysis theory to discuss the finite element interative calculate method . The convergence speed of this method is very fast. The result shows that material nonlinear will obviously lower the structural rigidity of [45 / 45] crossed angle ply shell, but the affect to the structural rigidity of perpendicularity symmetry ply shell is not so apparent.Thirdly, while analyzing composite materials shell structure, the structural pre-flection nonlinear equation and engenfunction for resolving flection load are separately simplified in the axis symmetry shell's flection finite element analysis. This method enhances the efficiency of solving but not the accuraty, it especially suits cylinders for compressed natural gas vehicles's finite element analysis under axis symmetry loads condition. A'method of analyzing the stresses of the lining of Fiber Enlaced Composite Cylindrical shell under internal pressure is raised through building the theory equation with putting the ring shaped stiffener on the point of enlancing fiber. The result is good fit with the traditional finite element analyzing system.Finally, the use of visualization technology in every aspect of the whole course of optimal design is expounded, and the computer aided design system of composite materials shell structure -CMFCAD system is set up in this paper. The .correctness of composite materials shell design theory in cylinders for compressed natural gas vehicles is tested and verified through experiment.