Identification of the strain rate parameters for structural adhesives
Résumé
Structural adhesives are frequently used for applications (mostly in the automotive field) in which they are exposed to dynamic loads at high strain rates, that can cause plastic straining. Thus, such plastic behavior must be included and correctly reproduced by finite element simulations, for instance, to predict the worthiness of the structure against crash conditions. This work makes use of a recently developed general framework for non-linear constitutive models, based on a variational formulation in which, at every load increment, the updates satisfy a minimum principle. The problem is faced in general terms, operating on potentials from which the constitutive equations are obtained; thus different behaviors can be treated by the specific models which are implemented in the potentials. This paper describes the application of this approach to the case of a structural bi-component epoxy adhesive, with the aim of describing its behavior under compression at different test velocities. A widely available data set on compression tests (at strain rate up to 103 s−1) has been utilized to identify the parameters of the potentials and to evaluate the capability of the models to reproduce the measurements.
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