Simulation of damage in composites by means of interface models: parameter identification

The problem of parameter identification in interface models, which are here conceived for the simulation of delamination and debonding in composites, is discussed in this paper. An elastic-damage time-dependent model for the interlaminar surfaces of layered composites is first presented and its main features are discussed through an extensive parametric study; this constitutive model can be used to simulate both pure-mode and mixed-mode crack propagation phenomena. An indirect identification procedure is then described: it is based on the use of the extended Kalman filter and on an approximate, simplified computation of the sensitivity of the structural response to model parameters. This identification procedure is used to identify the interface model parameters on the basis of the responses of standard interlaminar fracture tests.