Damaged Zone Behavior Investigation Using Viscoelastic Models

In failure of orthotropic materials, there is a fracture zone devastated by the effects of the stress field at the crack tip. This region includes congeries of Micro-cracks and causes improving materials‟ properties against the failure by energy dissipation, but the failure analysis process is very difficult. So far, only the radius of this region has been investigated and to obtain the mechanical properties, less effort has been made. In this research, new approach, called “FPZ viscoelastic model” is proposed for accurate modeling of the crack tip local damage zone. This method incorporates numerical model, based on the viscoelasticity theory due to the growth of micro cracks, can accurately estimate mechanical properties of FPZ for orthotropic materials.