Impact Load-induced Fibre Reinforced Composite Material Delamination Growth Behavior

Continuous fibre-reinforced composite laminates have been become one of the most evolutive potential materials due to their excellent capabilities and have been used in many important structures.The composite materials frequently engender different mode damage when they have been used, such as landscape orientation matrix fracture, interface damage, fibre fracture and delamination. In the recent researches indicate that the strength of laminates in the direction along thickness is much lower than that along fibers. So delamination is a serious failure mode which can lead to premature failure of the composite laminates because of stiffness degradation. Delamination is a main hidden trouble in the structure of the composite materials. Hence, delamination mechanism, delamination effect have been discussed in a great amount of literatures in recent years, the research of improving its toughness and anti-delamination capability become more significance and valuable. In this paper several major problems about delamination growth with impact load have been studied thoroughly in theoretical and numerical analysis.In this paper, base on composite materials mechanics and fracture mechanics theory, a nonlinear finite element program is developed with the mode of secondary development of ANSYS software to study geometric nonlinearity, material nonlinearity, contact nonlinearity and delamination growth of composite laminates.Energy release rate is used to be the criterion of the delamination growth, the model can simulate crack growth by relieving the nodes coupling restriction, activate the spring element and contact element to simulate the short-fiber bridging force and the unpenetrability of the materials.Energy release rate and the stability of laminates in different impact energy have been studied in this paper, and compare with that not has interlaminar short-fiber. Result indicates that short-fiber can reduce energy release rate in crack tip, reduce the velocity of the crack growth, improve the stability.