Mechanics and Mechanical Engineering Vol. 20, No. 3 (2016) 331–345 c ⃝ Lodz University of Technology Comparative Studies by a Genetic Algorithm on the Mechanical Properties of PLA and Expoxy Biocomposite Materials Reinforced with Alfa Natural Fiber Samir Tadjedit Lahouari Temimi Ahmed Boutaous Faculty of Physics, U.S.T.O BP 1505 Oran, Algeria mokaddem.allel@gmail.com Allel Mokadem Faculty of Physics, Department of Materials and Components U.S.T.H.B, Algiers,Algeria Bendouma Doumi Faculty of Sciences, Department of Physics University of Moulay Tahar, Saida,Algeria Nadir Beldjoudi Faculty of Physics, Theoretical Physics Laboratory U.S.T.H.B, Algiers, Algeria Received (15 January 2016) Revised (27 January 2016) Accepted (28 May 2016) The natural fibers are indeed a renewable resource, biodegradable and naturally with technical qualities and very high mechanical properties. The mechanical properties of reinforcement biocomposites as alfa / polylactic acid (PLA) are largely conditioned by the interfacial bond between the two materials (fiber and matrix). To characterize this link and locate damage to the fiber-matrix interface, we used a genetic approach based on the Cox model and formalism of Weibull. This model taking into account the micro- mechanical behavior of the three composite and biocomposites materials: Glass/epoxy, alfa / epoxy and alfa / PLA. The results of this simulation show that the damage level of the interface is related to the nature of the materials used and the applied mechanical stress, and has shown that the green material alfa / PLA is stronger than the biomaterial alfa / epoxy. The results of this modeling are in agreement with those obtained experimentally by Antoine et al. So the natural fibers have a very important role in enhancing the mechanical strength of composite and biocomposites materials. Keywords : glass, interfaces, biocomposites, PLA, alfa, epoxy.