STRESSES DURING THERMOSET CURE

Production problems attributed to excessive stresses generated during the cure of epoxies led us to develop a formalism to predict these str esses. In our first studies, we developed a fundamental understanding of the complex evolution of viscoelasticity as the cure progresses. We then incorporated these results into a proper tensorial constitutive equation that was integrated into our finite element codes and validat ed using more complicated geometries, thermal histories, and strain pr ofiles. The formalism was then applied to the original production prob lem to determine cure schedules that would minimize stress generation during cure. During the pursuit of these activities, several interesti ng and puzzling phenomena were discovered that have stimulated further investigation.