Issue 13

Ahanchian Mohammad et alii, Frattura ed Integrità Strutturale, 13 (2010) 31-35; DOI: 10.3221/IGF-ESIS.13.04 31 Investigation of crack propagation in single optical fiber composite with thermal influence by finite element method Ahanchian Mohammad Ph.D. Candidate of Mechanical Engineering, De La Salle University Arzumanyan Hovhannes, Verlinski Sergey Assistant Professor of Department of Mechanics and Machine Sciences, State Engineering University of Armenia A BSTRACT . Two parallel comparative ‘Conventional Method and Computer Simulation using ANSYS software’ for prediction of crack growth and its behavior in optical fiber are studied and presented in this work. Corresponding finite element analysis was performed to determine the evolution of stress and strain states. The method is developed and combined with the modified J-integral theory to deal with this problem. The effects of crack length, temperature and mechanical forces are investigated by Finite Element Method in the cracked body. The conditions where the Mode I stress intensity factor motivate fracture occurrence is investigated and variations of the different cases are discussed. The most deleterious situation is found to be that wherein the entire model reaches rupture at some stage. The accuracy of the method is investigated through comparison of numerical results with computerized simulation using commercial ANSYS software. K EYWORDS . Crack propagation; Fracture; Temperature loading; Stress intensity factor; Breaking force. I NTRODUCTION ecently, an increasing attention is attracted by a new development of microstructure optical fibers in telecommunication systems. An optical fiber is a single, hair-fine filament drawn from molten silica glass [1] which is widely used in communication systems. Optical fibers are going to be employed as a replacement of metal wires as the transmission medium in high-speed, high-capacity communication systems and are superior to that of conventional copper cable. In this design data is converted into light then transmitted via fiber optic cables with less loss. One of the most important usages of optical fibers is to transfer data sometimes in very long distance s [2]. This duty could not be performed with physical failure and if the fiber core transpires fracture the data would not be transmitted properly. Since the main failure mode of fracture in optical fiber is mechanical fracture [3] more consideration is needed regarding the strength and associated reliability [4] of optical fibers which are major technical concerns before they can reach the full potential for telecommunication industry. Inevitable presence of sub micro cracks, flaws and hollows in the intersection of materials as a result of manufacturing and further processe s [5] or on the surface of glass under either tension or bending [6] play a significant role for concentrating stress near the crack tip which decrease the strength of the material. Nevertheless, unfortunately, very few investigations have been conducted on their mechanical and fracture behavior of microstructure optical fibers [4]. These studies were conducted without considering temperature impacts. The goal of the current study is to investigate the fracture behavior of microstructure optical fibers containing surface cracks and environmental effects like temperature. Therefore, finite R