Influence of the degree of stress triaxiality and the lode angle on the fracture behavior of window frames

Abstract

The validity of the fracture models, based on plastic strain tensor invariants, is limited to predicting failure under specific stress states. The models can be made more general by including two additional characteristics of the stress state – the stress triaxiality and the Lode angle. In the present work, these characteristics are used in identifying the type of stress state and expected type of failure during the opening of a corner joint of a window frame, made of UPVC profiles. The characteristics are calculated from the principal and the equivalent (von Mises) stresses, obtained by numerical simulation with Ansys Mechanical. The obtained results for the type of stress state and expected type of failure can be used in the selection of a model for the analysis of crack formation processes and fracture of window- frame corner joints.