Step pressure and blast responses of clamped orthotropic hemispherical shells

Abstract

This work is concerned with studies on the axisymmetric free vibration and dynamic response of polar orthotropic clamped hemispherical shells subjected to suddenly applied loads, including idealized step pressure, a rectangular pressure impulse of finite duration and realistic blast pressure over the total or partial area. The mathematical model is formulated in terms of the mid-surface displacements and cross-section rotation with effects of transverse shear strain and rotary inertia taken into account. The Rayleigh-Ritz method is employed to solve the hemispherical shell vibration problem by assumed modes in Legendre polynomials, and the normal mode superposition is used in the analysis of its dynamic response. Numerical results for the natural frequencies, mode shapes, structural deformation and dynamic stresses are obtained with the fiber orientation parallel or perpendicular to the meridian direction as a design guide.