二维叠层C/SiC复合材料低能量冲击损伤实验

C/SiC复合材料是航空航天器中的耐高温材料，其服役环境存在低能量冲击源且关于此类冲击事件的研究相对较少。本文主要采用落锤冲击系统性地揭示2D叠层C/SiC复合材料平板的抗低速低能量冲击性能，通过改变冲击能量考核不同单层厚度和平板厚度的抗冲击性能变化，并利用CT技术进行冲击后无损检测，分析结构内部细观损伤。结果表明：冲击载荷下，C/SiC复合材料按冲击载荷变化可分为线性、屈服和回弹3个阶段；典型冲击损伤形式包含局部压溃、分层、纤维断裂及基体微裂纹；同等结构厚度，单层厚度越大C/SiC复合材料平板冲击变形和冲击损伤越小，冲击阻抗值越高；同等单层厚度下，结构总厚度较大的C/SiC复合材料平板冲击损伤较小，冲击阻抗较大。因此，C/SiC复合材料的预制体层数与结构厚度对低能量冲击源较为敏感，且减小单层厚度及增加结构总厚度可明显提高其抗冲击性能。

Low energy level impact damage on 2D C/SiC composites: Experimental study

C/SiC composites as high-temperature resistant materials in the fields of aeronautics and astronautics will encounter low-energy impact sources in their service environment. This paper systematically reveals the impact resistance performance of 2D laminated C/SiC composite materials using drop-weight impact equipment. We study the impact resistance with different prefab thickness and structure thickness under different impact energy conditions. The structure damage is analyzed by the CT nondestructive testing technology, showing that the impact load can be divided into three stages: linear elasticity, yield, and rebound. Typical forms of impact damage include matrix crushes, delamination, fiber fractures and matrix microcracks. With the same structure thickness, C/SiC composites with larger ply thickness have less impact deformation, less impact damage and higher impact impedance. For the same ply thickness, C/SiC composites with larger total thickness have less impact damage and larger impact impedance. Therefore, the number of prefabricated layers and structural thickness of C/SiC composites are sensitive to low energy impact sources. Thus, we can improve the impact resistance of C/SiC composites by reducing the thickness of the prefab and increasing the total thickness of the structure.