Mechanical Behavior of Resin Hybrid Braided Composites Considering Micro Fractures
Kentaro SAKODA, Amane KITAYAMA, Akio OHTANI and Asami NAKAI
Abstract:Hybrid composite materials are the material consists of more than two kinds of components. In hybrid composite materials, we have extended the concept of fiber hybrid and proposed resin hybrid and interphase hybrid. Resin hybrid composite materials mean that some types of matrix resin are used in one composite material. In this study, the concept of resin hybrid composites was applied to braided composites and the fracture mechanism was clarified. At first, the effects of position and the number of fiber bundle impregnated with flexible resin on the fracture mechanism, tensile properties and three point bending impact properties were investigated. Next, finite element analysis considering micro fracture such as fiber fracture, matrix crack inside the fiber bundle and delamination between two fiber bundles was proposed. By combining the experimental results and finite element analysis, the material constants such as Weibull modulus and interfacial shear strength of fiber bundle impregnated with normal and flexible resin were identified. Then, the prediction of stress-strain curve of resin hybrid composites became realized by considering geometry of textile and micro fractures. The fracture mechanism was different by changing position and the number of fiber bundle impregnated with flexible resin. Finally, some kinds of design guides were proposed. It was considered that these techniques are useful for control of the fracture and the optimization of the material design of resin hybrid composites in which the progress of micro fractures became more complex. Key Words:Hybrid composite materials, Resin hybrid composites, Fiber bundle impregnated with flexible resin, Finite element analysis, Micro fracture, Prediction of stress-strain curve, Fracture mechanism, Design guides