I. Introduction
The interaction between the semi-infinite crack and a neighboring micro-crack has been studied by several researchers [1-3]. In this paper, based on the strain energy, this study is devoted to determining the influence of microcrack on the semi-infinite crack. During the propagation of semi-infinite crack, the strain energy is mainly based on the stress field found by H. Hamli benzahar [4]. The problem is formulated by a brittle material of a thin thickness, cracked at the end, having a microcrack varies around itself by an angle α and around d the semi-infinite crack by an angle (see Figure 1). The cracked model is subjected to a uniform load making opening of semi-infinite crack according to the first mode of rupture (Mode I). Using the mathematical approaches, the constraints and strains fields of a micro-crack and semi-infinite crack are formulated by using of the complex potentials theory [5]. The strain energy rate is defined as the energy released during the cracking of a brittle or ductile material [6]. To determine the evolution of the semi-infinite crack, several researchers used the principle of J-integral [7-8]. Experimental and numerical results show that macroscopic specimens which contain microscopic defects producing local stress concentrations [9-10]. In brittle materials, the failure is considered to be an energy-consuming phenomenon, taking into account the energy state of the atoms before and after cracking. [11]. This study is divided to two parts;
According strain energy results, the positioning of the microcrack can amplify, reduce and sometimes stop the propagation of the semi-infinite crack.