The prediction of the elastic critical load of submerged eccentric cylindrical shell based on vibro-acoustic model

An effective new approach to nondestructively predict the elastic critical hydrostatic pressure of a submerged eccentric cylindrical shell is presented in this paper. According to the geometry characteristic of the cross section of eccentric cylindrical shell, the eccentric problem is transformed into the problem of variable thickness in the circumferential direction. The vibration equations considering hydrostatic pressures of outer fluid are written in the form of a matrix differential equation which is obtained by using the transfer matrix of the state vector of the shell. Depending on wave propagation approach, the data of the fundamental natural frequencies of the shell with various eccentricities under different hydrostatic pressure and boundary conditions are obtained by solving the frequency equation with a Lagrange interpolation method. The curve of the fundamental natural frequency squared versus hydrostatic pressure is then drawn with the data, which is approximately straight line or parabola that depends on the eccentric value. The elastic critical hydrostatic pressure is therefore obtained while the fundamental natural frequency is assumed to be zero according to the curve. The results obtained by the present approach show good agreement with published results and finite element results.