Formulation and implementation of hybrid-Trefftz stress elements for cohesive fracture

The hybrid-Trefftz stress finite element model is formulated to implement the fracture analysis of quasi-brittle materials using a cohesive model. The response is assumed to be geometrically linear and the bulk material to respond elastically. A discontinuous cohesive fracture model is used for tension dominant processes. Besides the derivation of the hybrid-Trefftz stress model, the approximation basis is defined and the procedure to detect and to implement the onset and propagation of damage and fracture through the domain of the element is outlined.