A variational approach to brittle fracture and cohesive delamination:modelling and technological applications

A new computational model is used for the study of fracture phenomena in homogeneous and composite materials. The computational model is based on the coupling between the phase field model and the cohesive zone model within the framework of the finite element method. This model is adopted from literature and consistently extended. The enhancements enclose the combination of the model with plasticity and its extension to the 3D finite elasticity framework. This extension is formulated in a consistent way by means of the variational approach. The model is validated through numerical examples mostly based on experimental results. The experiments are designed and performed by means of experimental facilities suitable for micro testing. The numerical simulations comprehend problems at different scales of homogeneous and composite materials in the bi-dimensional and three-dimensional space. The model results particularly appropriate for many technological applications. Among the different applications, the following cases are analysed: the competition between crack propagation and plasticity; the adhesive wear phenomenon considering the fracture of the micro asperities of two surfaces in contact; the mechanical behaviour of a nanolaminate and a microlaminate; the interaction between crack propagation and delamination. In the latter application is where the model shows its strength. The competition between crack propagation and delamination in composite materials is simulated without the necessity of remeshing or crack tracking algorithms. The model is particularly suitable for the exploitation in many engineering industrial fields.