Deformation and stress build-up in bi-material beam specimens with a curing FM300 adhesive interlayer

A dynamic mechanical analyzer was used to measure warpage of bi-material beam specimens with a curing adhesive interlayer during the cure cycle. Specimens consisting of a steel substrate, a curing FM300 adhesive layer, and a pre-cured composite substrate were subjected to a variety of cure cycles to determine the effect of cure time, cure temperature, and ramp rate in single- and multi-hold cycles on the development of warpage and residual stress. Experiments and a developed mathematical model showed that warpage and residual stress can be reduced if cure cycles are carefully chosen with respect to the cure kinetics and property evolution of the adhesive.