Creep instability analysis of viscoelastic sandwich shell panels

Abstract

This paper considers the creep instability analysis of time-dependent sandwich cylindrical and spherical shell panels of quadrilateral planforms having elastic faces and viscoelastic cores according to the first-order shear deformation theory. The viscoelastic properties of the core are extracted based on the Boltzmann integral law. The equilibrium equation is expressed utilizing the virtual work principle. The space and time parts of the displacement vector are approximated using the simple HP-cloud mesh-free method (which has H refinement and P enrichment properties), and the exponential time function, respectively. The stiffness and geometry matrices are constructed in the Laplace–Carson domain. Finally, the time behavior of viscoelastic sandwich shell panels under in-plane compressions is predicted by solving the eigenvalue problem in the Laplace–Carson domain. Also, the maximum compressive load is determined which can be applied to the time-dependent sandwich shell panels without any creep instability. This critical compression is less than the buckling load of the viscoelastic sandwich shell panel at time zero.