On stiffness properties of square honeycombs and other unidirectional composites

In this paper we consider stiffness properties of square symmetric unidirectional two-phase composites with given volume fractions. First, we compare the effective moduli of the stiffest possible (or softest possible) of such materials which satisfy transverse isotropy or square isotropy with that of materials satisfying 3D-isotropy. Next, we present some numerical FEM computations of in-plane stiffness properties of square honeycombs. Our results are compared with the effective moduli of the stiffest possible square symmetric composites. The numerical results are used to optimize the directions of square prisms in the core of sandwich plates with respect to stiffness. Our calculations can therefore be useful in connection with optimization of structural topology. (C) 2001 Published by Elsevier Science Ltd.