الفهرس 
CHAPTER 1: Review and Literature SurveyOnly 14 pages are availabe for public view
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Abstract
In last decades, hybrid composite materials play a competitive role in many industrial applications such as electrical and electronic industries. Copper/Glass-Reinforced epoxy laminate is a hybrid composite that is used in almost all electronic devices. Since these elements undergo different stress amplitudes under different working conditions, therefore the fracture toughness of such material is important to understand the failures occurred under different operating conditions.
Micro-electrical-mechanical systems (MEMS) are made of components in the range of 1 to 100 micrometers. These systems have a large application in electrical and electronic devices. The manufacturing of MEMS is categorized under semiconductor device branch fabrication. The performance of such precision material very strongly depended on the mechanical and fracture properties of the composite material they get fabricated from. A MEMS thin strips are manufactured by bonding a thin copper film on a substrate of glass-reinforced laminated fabric with an epoxy resin binder. Generally, the tested samples are glass fiber laminates with a 1.5mm thickness having 35-micron copper layer.
The present work aims to investigate the fracture behavior of copper/epoxy composites by experimentally measuring and predicting their fracture toughness and by numerically building the model. At the first stage, a center-notched tensile specimen is used to measure fracture toughness in mode I at room temperature. The results showed that, an average fracture toughness of with SDV 0.5556 is found. At the second stage, X-FEM is implemented to a simple numerical model to predict the fracture toughness of such a material and to measure stresses induced through the specimen during applied stress. The variation of both, predicted fracture toughness and cohesive stress at the crack face with crack opening displacement, shows that by using finite element method results are in good agreement with the experimental results.
On the other hand, the essential work of fracture for these composite is investigated. At this end, two sets of samples were cut; first ones are in the form of a flat specimen with a small hole at the center for size effect tests. Whereas, the second ones are double edge notch (DENT) specimens for essential work of fracture tests. The fracture toughness of such material is measured using essential work of fracture tests. These types of material are considered a quasi-brittle material which mainly anisotropic material, therefore, the size effect is tested over this material. The results showed that the essential work of fracture for this MEMS material is measured as 72.883 kJ/mm2 and is subjected to size effect which maked a reduction in nominal strength namely 15%.