Mehdi Fakoor - Assistant Professor
Mohammad Hossein Sabour - Assistant Professor
Nabi Mehri Khansari - Assistant Professor, ۳MSc. Student Department Of Aerospace Engineering, Faculty of New Sciences and Technologies, University Of Tehran, Tehran, Iran

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.

Viscoelasticity Model, Fracture Process Zone (FPZ), Orthotropic Materials, Micro-crack