The expanded metal sheets were folded with 11% work-hardening. These were subsequently used with resistance welding to construct X-type lattice truss sandwich panels having a core relative density of 0.17. The sandwich panels were tested in uniaxial compression and, for comparison, the method of finite elements was employed to simulate the measured compressive stress-strain curves. The peak compressive strength was 32% higher than that of pyramidal core sandwiches. The enhanced mechanical properties of the work-hardened X-Type lattice structures mainly originate from the contribution of straight struts with low degree of curvature and work hardening, rather than the two-dimensional staggered nodes.
Wave propagation in infinitely long hollow sandwich cylinders with prismatic cores is analyzed by the extended Wittrick-Williams(W-W) algorithm and the precise integration method(PIM). The effective elastic constants of prismatic cellular materials are obtained by the homogenization method. By applying the variational principle and introducing the dual variables, the canonical equations of Hamiltonian system are constructed. Thereafter, the wave propagation problem is converted to an eigenvalue problem. In numerical examples, the effects of the prismatic cellular topology, the relative density, and the boundary conditions on dispersion relations,respectively, are investigated.
