Damage assessment of GFRP pultruded structural elements

This study shows a procedure for the identification of the mechanical characteristics and dynamic parameters of glass fiber-reinforced polymer (FRP) pultruded elements. The matching between analytical model and experimentally acquired modal and natural frequency data is used to investigate the homogeneity of materials (resin and fibers) and the mechanical characteristics variation for pultruded profile with different cross sections, also in presence of induced damage. The experimental results are given primacy, and then the model must be modified by trial and error methodologies of model updating approach. This work depicts the sensitivity analysis based FE model updating procedure and its application to mechanical characteristics and damage assessment of different GFRP members from modal parameters. The accuracy analysis, that relies upon the relative confidence between the results (exp. and analytical) features a FE model of pultruded composite profiles with orthotropic behavior. The same structures were subjected to damage and their identification is based on dynamic response through the curvature mode shapes. This approach allows to know the location and size of damage, the change in dynamic characteristics and thus the decrease in strength and stiffness. The damage identification was carried out also with FE analysis by updating the undamaged beam model.