Abstract: The method developed in this paper is inspired hy the viewpoint in ref. [1] that sufficient attention has not been paid to the value of the generalized varialional principle in dealing with the boundary conditions in the finite element method. This, method applies the generalized varialional principle and chooses the series constituted by spline junction multiplied by sinusoidal junction and added by polynomial as the approximate deflection of plates and shells. By taking the deflect ion problem of thin plate, it shows that this method can solve the coupling problem in the finite element-semianalytical method. Compared with the finite elementt method and finite stripe method, this method has much fewer unknown variables and higher precision. Hence, it proposes an effective way to solve this kind of engineering problems by minicomputer.

Key words: Duffing-van der Pol system, two parameters, singularity analysis