Stiffness design, failure modes, and lightweight design of truss-lattice with filler sandwich plate under thermal loading

A homogeneous stiffness equation of a lattice with a filler has been obtained by the conservation of strain energy. Using this equation, the relationships between the physical and geometric factors of the truss, filler, and homogeneous stiffness were derived, and stiffness design criteria were obtained. The relationships between different thermal failure modes of the truss-lattice with the filler sandwich plate and its physical and geometric parameters were discussed, including their effects on global plate buckling, local plate buckling, truss buckling, and yielding. Strength improvement measures have been obtained. Failure maps with three geometric ratios and different physical ratios were obtained by failure mode analysis. Finally, a lightweight design method that achieves the strength and stiffness requirements was obtained based on four independent variables.