Abstract: The calculation of elastic deformations of corrugated diaphragms was given by orthogonal anisotropy plate theory[1], and its result agrees with the experimental results. But it has never been discussed seriously how the number and form of convolutions affect the elastic deformations and stress distributions of anisotropy plate. As a result, adaptable limits of orthogonal anisotropy plate theory cannot be indicated when it is used to calculate diaphragms. It is said that the theory is fairly good for calculating elastic deformations of the diaphragms which have more convolutions. It is also said that the error in calculating stresses is rather large. This paper, by using the toroidal shell theory, presents the calculation of deformations and stresses of three-convolution circular arc corrugated diaphragms both. symmetrical and unsymmetrical, compares its result with that of the orthogonal anisotropy plate theory and gives definite adaptable limits of the latter theory.

Key words: Good" Boussinesq equation, multi-symplectic, conservation law