有横向纤维搭桥的脱层扩展稳定性分析

本文利用von Karman 非线性薄板理论, 求解了复合材料中有横向纤维搭桥作用的圆形薄膜脱层的后屈曲问题, 获得了桥联脱层均匀扩展的能量释放率和断裂韧性。通过大量的计算和分析得到一个重要结论: 搭桥纤维的存在不仅对脱层的初始扩展起到了增韧作用, 而且避免了脱层扩展的灾难性。同时定量地给出了搭桥作用对脱层初始扩展的增韧程度, 并且确定了桥联脱层扩展稳定与不稳定的分区, 对不稳定脱层还给出了失稳扩展的范围及动态效应的估计。 

ANALYSIS ON STABILITY CHARACTERISTICS OF QUASI STATIC GROWTH OF A BRIDGED DELAMINATION IN COMPOSITES

In this paper, some new results of axisymmetric post buckling and stability characteristics of growth of a thin film delamination bridged by through thickness fiber tows in a 3D composites are presented. An iterative procedure combined with Taylor's series expansion is used to generate a family of nondimensionalized post buckling solutions of the thin film delamination based on von Karman's nonlinear plate theory. The energy release rate G and the fracture toughness Γ ( ψ , Δ c 1) associated with uniform propagation of a circular delamination are obtained. An important conclusion that the bridge force not only increases the initial growth strain ε * 0 but also obstructs the catastrophic growth of the delamination is drawn from numerical results. In addition, quantitatively the following results are derived: (1) the effect of bridge force on the initial growth of the delamination during post buckling phase, and (2) the regions of stable and unstable growth of the bridged delamination, and (3) the assessment of the range and the dynamic effect of unstable growth for the delamination propagating from unstable to stable.