Bi-modal buckling of optimised truss-lattice shear panels

A truss-lattice panel is modeled under shear loading, up to and beyond the critical buckling load. Nondimensional buckling loads and corresponding buckling mode shapes are obtained for such panels with increasing numbers of diagonally placed internal struts. A method for minimum-mass optimization of the truss lattice is given, based upon simultaneous in-plane and out-of-plane buckling. The finite element method is applied to examine the buckling performance and postbuckling stability. The postbuckling response of the optimized truss lattice is shown to be stable in all cases. The advantages of using the truss-lattice structure are demonstrated by comparing the volume requirements with those of a conventional continuous shear panel, based on the load carried and the buckling capabilities. It is shown that although the continuous shear panel is more efficient for heavy load applications, the truss lattice offers potential weight savings when lighter loads are applied.