The mechanics of pyramids

The elastostatic fields and free-vibration characteristics are studied for a class of continuous solids in the shape of homogeneous or layered pentahedral pyramids. The pyramids possess an arbitrary number of linear elastic layers containing dissimilar elastic constants. The layers are assumed to be perfectly bonded in the out-of-plane direction of the pyramid. The change in elastic stiffness across each interface requires a model that allows for a jump in displacement gradient at these location. A discrete-layer representation is used that combines the Ritz method with polynomial in-plane approximations with one-dimensional Lagrangian interpolation polynomials in the thickness direction. The free-vibration characteristics are examined for a variety of isotropic and anisotropic materials and representative bulk stiffness estimates are given for homogeneous pyramids under static deformation.