In this paper the experimental study of the fragility, ductility fracture and the mechanical behavior of high-density polyethylene pipe cracked is subject with know the damage law taken account of the deformation velocity which related to the cracking speed. The ductile fracture of HDPE pipes is characterized by a short crack that propagates rapidly perpendicular to the direction of stretching. The tests were carried out on different specimens cracked and uncracked taken from high density polyethylene (HDPE). The main aim of this study is studied the damage and material HDPE with two cases cracked and uncracked specimens of HDPE and knowing the physical quantities and the understanding of the effect of the deformation velocity on the mechanical behavior.