冰球高速钝性冲击载荷作用下复合材料蜂窝夹层板的动态力学响应

Aircraft structure under hail ice attract is a typical high velocity blunt impact behavior. The theoretical analysis, experimental research and numerical simulation methods have been employed to investigate the dynamic response of composite honeycomb sandwich panel under ice sphere impact. The failure modes, damage distribution and form of face-sheet, cohesive zone and honeycomb core of the panel have been studied by ice sphere impact experiments with different impact velocities, incidence angles and characteristic parameters of the panels. Contrasting by 3-point bending tests and low velocity pendulum Impact tests, the different of damage form and failure modes results between them and ice impact tests have studied. The stress transfer path and damage propagation path in the panel when it under ice sphere impact have been simulated by FEM. The failure sequence, deformation evolution and failure modes conversion also been researched with impact energy varying. The impact energy threshold of initial BVID damage and failure mode changing have been obtained and the relationship between impact energy and damage degree has been studied. A damage evolution model of it under ice sphere impact has been established. The residual compressive strength and bending strength have been tested and the residual strength theory of it has also been established.

飞机机体遭受冰雹袭击是一种典型的高速钝性冲击载荷下结构动态响应行为。本项目采用理论分析，实验研究和数值模拟相结合的方法对冰球冲击载荷作用下复合材料蜂窝夹层板结构的动态响应进行研究。通过实验研究冰球冲击速度、入射角度和板材材料特征参数改变对其面板、粘接层和蜂窝夹层等构成元素的失效模式、损伤分布及截面变形形态的影响。通过准静态三点弯曲，低速摆锤撞击与冰球高速冲击该型板材的实验进行对比，研究其损伤形态和失效模式间的差异及机理。结合有限元仿真，明确冰球冲击时板材内部应力传递和损伤扩展路径，研究冲击能的变化对板材结构的失效次序、变形形态演化及失效模式转换的影响。寻找板材初始失效（面板无可视损伤但蜂窝局部塑形屈曲）和失效模式发生转换时的冲击能阈值，比较阈值前后冲击能与板材损伤程度间关系的变化情况，建立含多种失效模式的板材损伤演化模型。测试含有冰球冲击损伤板材的剩余强度，建立对应的该型板材剩余强度理论。

碳纤维复合材料曲面板结构在冰球冲击载荷下的破坏是一种典型的钝性冲击失效响应。本项目首先研究了轻质自然纤维增强复合材料的动态拉伸性能，并发现了其混杂纤维的不同比例对复合材料应变率效应的影响。同时，该研究还发现了宏观横向断裂的复合材料在微观上纤维为剪切破坏失效，并为相关混杂自然纤维增强复合材料的优化设计提供了理论支撑。其次，本项目研究了FEM，SPH和ALE等不同数值计算方法对冰冲击载荷的仿真模拟精度和效率的影响，并利用S-ALE算法实现了不同体积比的含随机分布气泡的冰材料数值建模和仿真模拟。该研究在研究了气泡含量对冰动态力学性能研究的基础上揭示了应变率提升会使得气泡分布规律对冰动态强度影响削弱的现象。在此基础上，本项目进而研究了冰球冲击碳纤维复合材料曲面蒙皮板结构的动态响应，并发现了其在冰球冲击蒙皮隔段中心位置时约束边界的远端首先发生基体脱胶失效的现象，以及冲击蒙皮隔段法兰处时失效存在临界冲击能的现象。同时，该研究还结合实验与仿真结果解释了在不同冲击位置时法兰界面处基体开裂起始位置不同的力学机理。该研究为改善相关复合材料曲面板材结构的抗冲击设计提供了理论指导和评估方法。