Use of hybrid composites for the reduction of hygroscopic stresses at the edges of plates exposed to the symmetrical environmental conditions

The aim of this work is the reduction of the hygroscopic stresses at the edges of the hybrid composite for the symmetrical and constant environmental conditions. We noted during our search that the hygroscopic stresses calculated by the analytical method are maximum at both the edges of the laminated composite, in particular at the first times of the moisture diffusion. Therefore, a probable degradation of the laminated plates can be produced at the two edges. In this context and in order to limit these maximum stresses, we made some applications on hybrid composites in graphite/epoxy with polymer matrix. Firstly, we carried out a calculation of the moisture concentration from the initial until the saturation time, for two applications suggested A and B, of a hybrid composite. Secondly, we calculated the hygroscopic stresses for each application (cases A and B). An appropriate choice of the stacking hybrid sequences [θ/−θ] will be useful considerably in the reduction of these hygroscopic stresses.