Towards the design of sandwich panel composites with enhanced mechanical and thermal properties by variation of the in-plane Poisson's ratios

The finite element (FE) method has been used to study the mechanical and thermal properties of both conventional and re-entrant (i.e. negative Poisson's ratio) honeycombs, which may be used as the cores of sandwich panel composites. Failure of the honeycomb structures was simulated using a crack propagation method developed in-house. The cell-wall stress build up in the conventional honeycomb was calculated to be significantly reduced relative to the re-entrant honeycomb under (2D) hydrostatic loading, implying that the conventional core will undergo significantly less internal damage than the re-entrant core. Conversely, the re-entrant honeycomb performs better than the conventional honeycomb under thermal loading conditions. The size and pathway of the crack formed during the simulation is dependent on the failure stress distribution used in the crack propagation routine. (C) 2003 Elsevier Science Ltd. All rights reserved.