Abstract
The predictions of two viscoelastic constitutive models: one in an integral form and the other with a differential form, are compared with the experimental results presented in Part I and in Ref. 3. The experimental data include the stress-strain response ofthe epoxy resin under various loading paths with different strain combinations, and the stress envelopes of the same octahedral shear strain amplitude but with different strain rates and a cyclic ratcheting strain test. The results of this investigation indicate that while both n~nlinear viscoelastic constitutive models predict the general trend of the experimental behaviour, the quantitative comparison is not accurate enough, especially when a high hydrostatic stress component is present or under cyclic loading. It is found that the stress envelopes predicted by a modified von Mises (Stassi) criterion have a better correlation with the test results.