Identification and measurement of ductile damage parameters

The possibility of extending fracture mechanics concepts and design criteri a to ductile failure is an issue that has attracted the attention of many r esearchers. Many models that address this are available nowadays. For these , two kinds of approach are widely used: the porosity-based model proposed by Gurson and the continuum damage mechanics (CDM) approach. Any new user t hat has to deal with these models for the first time is often hindered by t he difficulty of finding in the literature, or measuring, the material para meters necessary. In addition, the use of these models, which are often ava ilable already built into commercial finite element codes, requires great e xperience and attention in order to avoid the danger of 'numerical traps an d tricks'. Here, constitutive models based on the plasticity criterion for porous media given by Gurson, and the CDM framework proposed by Lemaitre ar e reviewed, giving attention to identification procedures for the damage pa rameters.