抄録
A computer program of three-dimensional intelligent finite element method by using shell elements has been developed in order to obtain the optimum fiber orientation and the optimum stacking sequence of laminate composites. The developed computer program can treat a balanced symmetric laminate composites. The design object to determine the fiber orientation and the stacking sequence is the strength of laminate. The strength is evaluated by the F-value of each lamina based on Hoffman's failure criterion. And the optimum fiber orientation and the optimum stacking sequence are determined by the minimum thickness with the F-value satisfying the allowable value. As the numerical examples for actual structures, the determination of fiber orientation in each layer for a cylindrical pipe and a T-type structural component under combined load has been carried out. In the case of cylindrical pipe under three loading conditions such as the combined internal pressure and tensile load, the only torsion load and the combined torsional and tensile load, the optimum laminates to withstand hoop stress, axial stress and shearing stress for each loading condition were obtained. Then, the optimum laminates of T-type structural component for each loading condition were estimated by using the initial fracture load. As the result, it is recognized that the proposed method is very useful for the structural design of composites.
