Abstract: Finite element analysis (FEA) of filamentwound composites is the foundation of mechanical research and application of these materials. In this article, a finite element method (FEM) of filamentwound composites is developed which is based on the micro stiffness model of a filamentwound composite. The micro stiffness model is based on Fourier series. The micro stiffness is brought into FEM through a mapping relation between the micro stiffness field and macro structure. Anisotropic element is used in this method. No complicated treatment on geometrical modeling and meshing is needed. The flow chart of this method is first established, and MATLAB is used for developing a program for the micro stiffness model. The APDL language is used for developing the program of geometrical modeling, meshing, and inputting material properties, etc. Finally a numerical example is analyzed. The result of the example shows that the stress and strain of every layer is in periodical distribution, and that the local stress is amplified by the undulation of the fiber. Direction shifting of the fiber causes shear stress shifting, and the reduction of local stiffness causes the local strain to be larger than the average strain. Compared with traditional methods, the application of micro stiffness in FEM can better indicate the effect of micro structure on stress and strain.

Key words: filament, composites, finite element method, micro stiffness, structural analysis