Thermomechanical coupling

In the aerospace industry, composite laminates made of unidirectional plies of continuous fibers and polymer resin are widely used, thanks to their good specific mechanical properties and excellent fatigue resistance. However, the thermoelastic properties of fibers and matrix, on the one hand, and unidirectional plies, on the other, are very different and highly anisotropic. As a result, temperature variations induce, through prevented differential thermal expansion, intra- and inter-laminar stresses that can be significant. The first consequence of this thermomechanical coupling is the creation of thermally-induced residual stresses when the parts cool down from their consolidation temperature, residual stresses that manufacturers seek to minimize, in particular by optimizing manufacturing cycles. The higher the baking temperature, the greater these stresses will be, as is the case for...