Snap-through of unsymmetric fiber-reinforced composite laminates

An approximate theory based on assumed strain and displacement fields, the Rayleigh-Ritz technique, and virtual work is used to predict the snap-through forces and moments for three families of unsymmetric fiber-reinforced composite laminates. Unsymmetric laminates generally have two stable equilibrium configurations when cooled from their elevated cure temperature, and it is the moment required to snap the laminate from one stable configuration to the other that is the subject of this paper. A simple force-controlled experiment is described which is used to measure the snap-through moment and the characteristics of the configuration change, by way of strains, in four laminates. The correlation between predicted results and experimental measurements is quite good, both in terms of moment levels and in terms of strain response. (C) 2001 Elsevier Science Ltd. All rights reserved.