| In Part I, a literature review of theories and experimental studies of the effects of high strain rates and temperature on the fracture, yield, and energy absorption capabilities of epoxy polymer materials has been presented. The objective was to summarize the likely influence of temperature and strain rate in automotive applications, especially in the cases of crash and environmental temperature differences. Theories on the yield of glassy polymer epoxies have been presented in Mathcad 8 computer programs, which are supported by the available experimental results for modified and un-modified epoxies at different temperatures. It was shown that the failure criteria working under static conditions work well under high strain rates.;In Part II, a series of peel tests with different configurations has been conducted with a new epoxy adhesive, representing the application of the adhesives in conditions in which both adhesive and adherend undergo plastic deformations. Failure criteria were investigated using a model that treats adherends as bi-linear, but the adhesive can be any type of nonlinear format; in this thesis, a discrete set of uniaxial stress-strain data. Plane stress, plane strain and uniaxial conditions were considered separately for both adhesive and adherends. Two major failure criteria were considered; i.e. critical Von Mises strain energy and critical fracture energy. |
