Papers by Author: M. Chabaat

Abstract: In this study, interaction between a main crack and a surrounding layer of micro cracks is considered. A stress field distribution induced during these interactions is obtained using Muskhelshvili’s complex variables formalism which relies on the Green's functions. The effect of amplification and shielding on the resulting stress field is shown, herein, through a study of mode I Stress Intensity Factor (SIF). To quantify these effects, orientations as well as positions of microcracks with respect to the main crack is taken into consideration. Obtained results are compared and agreed with those of other researchers.

Abstract: The present paper investigates interactions between a main crack and a surrounding layer of crazing patterns. Analysis of the stress field distribution as well as the energy induced during these interactions is based on the resolution of some equations along with appropriate boundary conditions and the use of a numerical approach. The effect of amplification and shielding on the resulting stress field is shown through a study of mode I Stress Intensity Factor (SIF). Besides, to quantify the effects of this damage on the main crack, it is shown that the Energy Release Rate (ERR) is defined as being a superposition of the energy released due to the linear propagation of the main crack as well as the one due to the translational change in the growth of the damage. It is also proven that crazes closer to the main crack dominate the resulting interaction effect and reflect an anti-shielding of the damage while a reduction constitutes a material toughness.

Abstract: The present paper deals with the interactions between a main crack and a surrounding layer of crazing patterns. Analysis of the stress field distribution as well as the energy induced during these interactions is based on damage criteria through the resolution of some differential equations conditions and the use of a numerical approach. The effect of amplification and shielding on the resulting stress field is shown through a study of mode I. It is proven, herein, that crazes closer to the main crack dominate the resulting interaction effect and reflect an anti-shielding of the damage while a reduction constitutes a material toughness.

Abstract: In this study, interactions between a main crack and a surrounding layer of crazing patterns are considered. Analysis of the stress field distribution induced during these interactions is based on the resolution of some differential equations along with appropriate boundary conditions and the use of a numerical approach. These equations are established according to Mohr’s criteria since the craze growth occurs along directions parallel to the minor principal stress axis. Because this damage can constitute an important toughening mechanism, the mode I stress intensity factor (SIF) is employed to quantify the effects on a crack of the damage consisting of crazing patterns. It is proven, herein, that crazes closer to the main crack dominate the resulting interaction effect and reflect an antishielding of the damage while a reduction constitutes a material toughness.

Abstract: In this study, interaction of a main crack with its surrounding damage, which consists of continuous lines of discontinuities, is analysed. To solve this complex problem, a Semi-Empirical Approach (SEA), which relies on experimentally measured crack opening displacements as the solution to this multiple crack interaction problem is suggested. The solution procedure is illustrated, first, for a particular case of the interaction of an array of horizontal and vertical crazes with a main crack, and second, for the generalized case to include the whole damage of crazing patterns surrounding the main crack. The results show that the crack Damage Zone (DZ) or the socalled Process Zone (PZ) interaction may either amplify or suppress the resulting stress field depending on the crack damage configuration. Green’s function for the Stress Intensity Factor (SIF) is employed to quantify the effects on a crack of the damage of continuous patterns of discontinuities. It follows from the analysis that an increase in the number of crazing patterns will amplify the stress at the main crack. It is also shown throughout this study that the overall effect of the damage is identified, as being an amplifying one and that the resulting local stress field would direct the propagation of the main crack since there is no toughening.