The aim of this work is to study the effect of hygrothermal aging on mechanical
properties of two composite materials (carbon fiber / epoxy and glass fiber E / vinylester). Two
stratifications are studied for each material. Both materials are exposed to two different
environments, the sea water and the deionized water at a temperature of 40°C. The kinetic of
material absorption is plotted. We see an irreversible degradation of material caused by exposure
time. The characterization of samples in the virgin state and the aged condition is achieved with
three points bending tests. We can see significant loss of mechanical properties due to
hygrothermal aging.