NUMERICAL EVALUATIONS AND THERMOMECHANICAL MEASUREMENTS FOR VISCOELASTIC AND NONLINEAR FRACTURE-MECHANICS BEHAVIOR OF POLYMERIC MATERIALS

Preliminary investigations and extended convergence analyses, performe d by using FE techniques to evaluate fracture parameters - stress inte nsity factor, J integral and energy release rate - in LEFM, are presen ted. Interesting information about mesh density related to computation al efforts, especially useful in non-linear problems, has been obtaine d from the analysis of results. Coupled thermoviscoelasticity based an alytical and numerical evaluations, concerning thermal field and dissi pation effects in stressed polypropylene specimens, together with ther mographical measurements are shown and compared. Furthermore, a thermo mechanical approach to EPFM is presented and evaluated by means of num erical simulations and experimental tests on polypropylene.