DETERMINATION OF RESIDUAL-STRESSES USING INCREMENTAL LINEAR ELASTICITY

An incremental linear elastic constitutive equation was used to calcul ate the residual stresses generated in polymer systems, with emphasis on thermosetting systems which are curing under dimensionally constrai ned conditions. The equations necessary to calculate the stress due to cure, shrinkage due to cure, thermal stress, glass transition tempera ture and thermal expansion coefficient as functions of the polymerizat ion history are derived. Residual stress data are presented for an epo xy cured under conditions of uniaxial (one-dimensional) and volumetric (three-dimensional) constraint. It was found that for anhydridecured epoxies the unaxial stresses due to cure are small, especially in comp arison to the residual uniaxial thermal stress. For conditions of volu metric constraint it was found that both cure stresses and thermal str esses are large in amine-cured epoxy resins.