ABSTRACT
The constitutive equations of resins that take into account viscoelasticity and damage are of paramount importance. Particularly when considering the durability of CFRP, since the fibers exhibit no temperature and time dependence, and the interface exhibits no temperature and time dependence, ultimately the temperature and time dependence of the resin governs that of CFRP. It is noteworthy that although the fibers, which bear almost all the load, exhibit no time dependence, they do not degrade over time. However, since the resin exhibits temperature and time dependence, its strength decreases, ultimately leading to the overall failure of the CFRP. In other words, the resin should not be underestimated in terms of its degradation, even though it does not share the load. The durability of CFRP is still dominated by the resin. Therefore, it is extremely important to understand the viscoelastic and damage properties of the resin. This chapter introduces various insights into this topic from multiple perspectives, in order to elucidate this important issue.
