Analytical Prediction of Indentation Response of an In-Plane Prestressed Cylindrical Composite Sandwich Shell Indented by a Rigid Blunted Indenter

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

Keywords:

cylindrical composite sandwich shell , indentation response