Free vibration analysis of a hermetic capsule by pseudospectral method

A pseudospectral method is applied to the axisymmetric free vibration analysis of a hermetic capsule. The displacements and the rotation of a hermetic capsule are expressed by the Chebyshev expansions. The equations of motion are collocated to yield the system of equations in the hemispherical regions and the cylindrical region separately. The numbers of collocation points are chosen to be less than those of the expansion terms. The continuity conditions of deformations and stress resultants at the junctions serve as the constraints of the expansion coefficients. The set of algebraic equations is condensed so that the total number of the expansion terms matches the total number of degrees of freedom of the problem. Present method might be useful in the analyses of composite shell structures where different types of shells are joined together.