Non-local constitutive modelling by the Boundary Element Method

The conventional (local) constitutive modelling of materials exhibiting strain softening behaviour is suceptive to a spurious mesh dependence caused by numerically induced strain localization. Also, for very refined meshes, numerical instabilities may be verified, mainly if the simulations are performed by the boundary element method. An alternative to overcome such difficulties is the adoption of the so called non-local constitutive models. In this approach, some internal variables of the constitutive model in a single point are averaged considering its values of the neighbouring points. In this paper, the implicit formulation of the boundary element method for physically non linear problems is used with non-local isotropic damage models. It is shown that the analysis become more stable in comparison to the case of a local application of the same models and that the results recover the desired objectiveness to mesh refinement.