Study On Structure And Mechanical Performance Of Three-dimensional Orthogonal Woven Composites

Since 1960s, the advanced composite, especially the advanced resin matrix composites, has been greatly developed in the world for its unique characteristic, and it has been one of the most important materials of modern aerospace industry. Because of the whole woven of introducing Z-direction, three-dimensional woven composite materials overcome the defects of the traditional laminate composite and improve the whole performance in each direction, and will widely apply in many industries, such as aerospace industry etc.In this paper, the woven technique, molding technics of three-dimensional woven composite and mechanics-performance study method are summarized. Based on experience study on composite molding technics and performance testing of 3D orthogonal woven composite with different structure parameters, including performance after impact, a unit cell structural geometrical analysis model of three dimensional woven perform is established, analyze the linear-elasticity mechanical performance using averaging stiffness approach and discuss the effect principle of 3D orthogonal woven structural parameters to its composites' fiber volume fraction.Experimental study on performance after impact to the three-dimensional orthogonal woven composite using drop hammer lacquer film impact machine, including impact damnification area, residual stress and the tensile strength of 0°,30°,45°,60°,90°etc. The result indicates that damnification area increases with the addition of impact energy, and they have a direct ratio relation. The tensile strength after impact decreases with the rise of impact energy, and when impact energy reach a specific value, the increase of impact energy almost has no effect with residual strength.According to the micrograph of the composite cross-section, the basic hypothesis related to the yarns configuration is presented. Based on the structural parameters of the three-dimensional woven structure, a unit cell structural geometrical analysis model is built up, and analyzes the linear-elasticity mechanical performance using averaging stiffness approach. The theoretical predictions of thickness of the woven structure, fiber volume fraction, and module are compared with the testing results and it shows a very good agreement. It proves the microcosmic structural geometrical analysis model's correctness, and can be use to predict fiber volume fraction of 3D orthogonal woven composites.We can find the effect principle of 3D orthogonal woven structural parameters to its composites' fiber volume fraction by studying on the unit cell structural geometrical analysis model.