Composites, in the past, have been mainly used for savings in secondary structures. With several advances made in understanding the behavior of composite materials, many fiber-reinforced polymer composite materials are finding increasing use as primary load-bearing structures and also in a wide range of high-technology engineering applications. The ability to tailor composites, in addition to their attributes of high stiffness-to-weight and strength-to-weight ratios, fatigue resistance, corrosion resistance, and lower manufacturing costs, makes them very attractive when compared with conventional metals. Of late there has been a trend towards lean weight vehicle structures that has paved the way for increased utilization of polymer composite materials in the automobile industry. The main drawback of composite systems is their inability to resist defect initiation and propagation when compared with metallic systems. Investigation in the past has shown that even low-energy impacts are capable of generating enough damage to cause significant reductions in their load-bearing capacity. [George C. Jacob et al, 2005]
The ability to resist defect propagation is characterized by the fracture toughness of the material. Fracture mechanics gives us a quantitative handle on the process of fracture in materials. Its approach is based on the concept that the relevant material property, fracture toughness, is the force necessary to extend a crack through a structural member. Under certain circumstances, this crack extension force (or an equivalent parameter) becomes independent of the dimensions of the specimen. The parameter can then be used as a quantitative measure of the fracture toughness of the material. [Marc Meyers, 2009]
Fracture toughness of fiber reinforced composite material is of great interest as well as its strength, because it is essentially important when fracture behavior of composites was investigated. For example, fracture mode of brittle matrix composites are strongly affected by the fiber fracture toughness as well as its interface toughness [David Arenc?n, 2009].
While many scientists have investigated the fracture toughness properties in various continuous fiber-reinforced composite materials there is no literature available on the fracture toughness properties dependent on impact test for carbon or glass fiber-reinforced composite materials, which can consider serious problem in a wide range of load-bearing engineering and industrial process applications primarily. Therefore, in this study, an attempt is made to determine the fracture toughness of continuous carbon and glass woven fibers composite material systems based on Polyphenylene sulfide as matrix as laminated composite materials with different fibers orientation and different number of layers experimentally and numerically by using finite element program code called [ANSYS 12.1].