In this article a closed form solution is derived for the deformation response of a spherical composite sandwich shell subjected to static indentation of a rigid blunted cylindrical indenter. The facesheet deflection is several times the laminate thickness so that bending moments may be neglected and only membrane forces are considered in the facesheet. In contrast to the existing analytical model for the indentation of spherical composite sandwich shells, in the present model, the stacking sequence of the facesheets can be completely arbitrary, so that the shear-extension coupling terms, i.e. 16A and 26A, can also be included in the analysis. Furthermore, in the present model the effects of the initial in-plane normal and shear forces on the edges of the sandwich shell are also considered. An improved contact law is derived based on the minimum total potential energy principle. The elastic strain energy, the plastic work dissipated in crushing the core and the external work are calculated using an appropriate shape function for the facesheet deflection. The relation between the indentation load and the transverse deflection is obtained by minimization of the total potential energy. Analytical predictions of the load-indentation response compare well with FEM results. The effects of ply thickness, stacking sequence, radius of the spherical shell and initial in-plane forces on the load-indentation response are studied and discussed.
