A multi-scale analysis of composite structures: Application to the design of accelerated hygrothermal cycles

Hygrothermal cycles are known to cause degradation of fiber-reinforced polymer composite materials due to moisture uptake and thermal expansion. The knowledge of internal stresses due to cyclic environmental conditions is necessary to forecast a possible damage occurrence in the material during its service life. The accelerated cycles are studied so as to define the material geometry and environmental conditions to reproduce the in-service material state in a shorter time. In the present work, a self-consistent (SC) model is used in order to predict the stress state at the microscopic scale (fiber and matrix) induced by the real and accelerated cycles. The main aim is to compare the local states induced by the real and accelerated cycles in particular near to the edges where hold periodic conditions.