These materials are visco-elastic in nature and thus, over time, may undergo creep and stress relaxation even at ambient temperatures. For many applications, service stresses are low compared to ultimate values and the effects are limited. However, for applications involving adhesive bonding and other load bearing applications, the consequences may have to be considered. Thus, it may be necessary to determine the limiting stress level below which creep rupture does not occur for applications such as anchoring. In complex loading systems such as shrinkage or differential thermal expansion and contraction, stress relaxation may alleviate stress concentrations. The extent of these effects is governed by factors such as degree of cross-linking in the resin and the type/level of filler, see for example (Mays, 1992).
