ECCM16 - 16 TH EUROPEAN CONFERENCE ON COMPOSITE MATERIALS, Seville, Spain, 22-26 June 2014 1 AN INVESTIGATION OF THE EFFECT OF THE MACHINING PROCESSES OF CIRCULAR HOLES ON THE MECHANICAL BEHAVIOUR OF FLAX FIBER REINFORCED POLYMER I. El Sawi a , Z. Fawaz b , Redouane Zitoune c , Habiba Bougherara a * a Department of Mechanical and Industrial Engineering, Ryerson University, Toronto, ON, Canada b Department of Aerospace Engineering, Ryerson University, Toronto, ON, Canada c Institut Clément Ader (INSA, UPS, Mines Albi, ISAE), Université de Toulouse, Toulouse, France *e-mail address: habiba.bougherara@ryerson.ca Keywords: Fatigue testing, Flax fiber, Machining, IR Thermography Abstract In this work we investigated the influence of the machining quality on the mechanical behavior of natural fiber reinforced composite material selected for manufacturing bone fracture plates. The material used in this study is a Flax Fiber Reinforced Polymer (FFRP). Two types of composite lay-up were used to conduct this study: [0] 16 and [±45] 16 laminates. The experimental study was carried out on several composite plates drilled with a Conventional Machining (CM) process using a cutting tool and an abrasive water jet machining (AWJM) process. In order to study the impact of the process of machining on the mechanical behavior of the composites, infrared thermography coupled with fatigue cyclic tests were performed to assess the temperature and the damage evolution in these FFRP plates. 1. Introduction Polymer materials reinforced with plant based fibers such as flax, hemp, jute and sisal have been considered by numerous studies as potential alternative materials to glass-fiber reinforced plastics (GFRP) [1,2,3]. Like GFRP, natural fiber based composites are inherently more susceptible to variations in manufacturing processes. Besides, in structural applications, such materials are often subjected to cyclic loads which cause progressive damage and may lead to long term failure of the structure. The origin of the present work lies within the framework of an ongoing research program on the development of bio-based materials for use in orthopedic long bone fracture plates. The bone fracture plates are structures that contain machined holes that allow their fixation on the fractured bone. These holes induce a discontinuity and strength reduction in the composite structure, which happens due to the development of stress concentrations around the notched area. It is important to understand the sensitivity of composite laminates to the machined edges and notches. Machined edges sensitivity has been influenced by many factors such as laminate (thickness, ply number, and lay-up), notch (dimension/diameter and shape), and material’s properties [4, 5, 6].