Abstract:

In the paper, room-temperature shape of unsymmetrically laminated composites is studied using finite element method. This is a nonlinear finite element problem with multiple equilibrium states. A degenerated three-dimensional shell element is adopted and the incremental Newton-Raphson method is used to silve the nonlinear equilibrium equation. The different eqilibrium states are obtained by prespecifying initial deflection. The tangential stiffness matrix is decomposed into [L] [D] [L] to determine the stability of equilibrium. Experiment is also done and the numerical results poncide on the whole with the experimental results.