3-D Finite Element Analysis Of Embedded Delamination Growth In Composite Panels

Continuous fiber-reinforced composite laminates have been used in many important structures. The properties of high ratio strength and modulus to weight make it become one of the most evaluative potential materials. But the strength of laminates along thickness is much lower than that of laminates along fibres. This disadvantage has seriously limited its development. Delamination is a main failure and a seriously hidden danger of the composites. How to improve its toughness and anti-delamination capability has become the focus of researches which scholars of the world carry out. Therefore, a simulation on delamination growth in composite panels has theoretical and practical significance.In this paper, a three-dimensional finite element model is established to simulate composite laminates with embedded delamination.The process of delamination growth is 'studied by using geometrically and contactually nonlinear and three-dimensional FEM code. The delamination growth is performed, based on the virtual crack closure technique and the current fracture criterion in mixed mode.Discrete crack model is used to simulate delamination. The method of nodes coupling is used to simulate delamination growth. First, the energy release rate along the front delamination area is calculated during numerical analysis. When it achieves the delamination growth criterion, the nodes coupling constrain are released and short-fiber bridging force is added. The short-fiber is simulated by a nonlinear spring element. Short-fiber bridging force is changed by the stiffness of the spring. In the way, redundant iteration is avoided.The GAP element method is used to compute contact question, used for to simulate that materials can not penetrate with each other. The convergence of the model can be enhanced, and redundant iteration is also avoided.Delamination growth in composite panels with interlaminar short-fiber is studied in this paper. Compared with delamination growth in composite panels without interlaminar short-fiber, the conclusion can be drawed that short-fiber can effectively enhance interlaminar toughness.