Estimation of model parameters in nonlocal damage theories by inverse analysis techniques

The parameters identification problem of the gradient-enhanced continuum damage model is examined by means of an inverse analysis. Different related issues are analyzed: (i) the investigation of the limits of applicability and predictability of the adopted numerical model and (ii) the problem of objectively extracting material properties from a structural response.A necessary condition for an adequate identification of the model parameters is the well-posedness of the inverse problem. The results show that this requirement is obtained only if additional averaged local experimental information is involved in the inverse procedure, in addition to the global structural force–deformation response. Moreover, the adopted numerical model reveals limitations in predicting the entire size effect curve of tensile tests on dog-bone-shaped concrete specimens.