Modello coesivo per l'avanzamento di fratture mediante rilascio nodale di strutture discretizzate con elementi finiti.

High speed MODE I crack growth in elastic-plastic materials, involving large scale plasticity and dynamic effects connected to rapid propagation, is faced through a cohesive model to compute force nodal release. As it is well known, the search of a maximum stress in the crack tip is not worthwhile in the elastic case, only field factors may be used instead. In the elastic-plastic case, hardening and softening due to geometric reasons or due to local damaging have a deep influence on the exponential behaviour of the measured stress field. However, it is possible to introduce a reference value (finite), which is the stress at the beginning of the softening zone. This entity is taken as a scale factor for cohesive force evaluation that is necessary for the accounting of the dissipated energy. In the present work a procedure to compute this reference value by stress-strain field is presented, for a variety of T-stress conditions. [ABSTRACT FROM AUTHOR]