Correlation of accelerated aging test to natural aging test on graphite-epoxy composite materials

In order to evaluate the degradation of the mechanical and physical properties of composites under ground environments, T300/AD6005 graphite-epoxy composite specimens were exposed to natural environments for 5 years and accelerated environmental conditions including ultraviolet radiation, temperature and moisture for 2000 h. It was found that transverse flexural properties were more sensitive to environmental damage in a composite than other properties. Matrix cracking and matrix loss were observed at the surface of aged specimens by using scanning electron microscope. In order to achieve the same effect on the material in a shorter time period, the accelerated factor, a, was introduced and determined for several mechanical properties by using proposed degradation equations of material properties and linear relationship between the natural and accelerated aging time.