A unified visco-plastic model for the stress analysis of adhesively bondedstructures

Previous work has identified the need for a multiaxial visco-plastic model that can be used in the stress analysis of adhesively bonded structures. Su ch a model should also be capable of reflecting the hydrostatic sensitivity displayed by such polymeric systems. This paper outlines the development o f an appropriate uniaxial model, discusses the role of the various paramete rs, and outlines methods of fitting actual experimental data derived from c reep, relaxation, recovery, and constant strain rate tests on two different adhesive systems. Two different schemes are then discussed to extend the m odel for multiaxial conditions. These have been integrated into a finite el ement code as user routines and derails of the tangential modulus matrix ar e briefly presented. Following benchmark testing, these models have been us ed to predict the rate-dependent response of an adhesively bonded structure with considerable success.