二维C/SiC复合材料低速冲击损伤特性的表征研究

DAMAGE CHARACTERISTICS OF 2D C/SiC COMPOSITES UNDER LOW VELOCITY IMPACT

为研究二维C/SiC复合材料的低速冲击损伤性能,采用落锤式冲击试验机进行低速冲击试验,并利用声发射技术对试验进行动态监测以及冲击后试样的检测。结果表明:冲击能量的大小是造成C/SiC复合材料损伤模式不同的主要因素,同时,声发射参数可以很好地表征C/SiC复合材料的损伤模式和损伤演化过程。在较低冲击能量下(3 J以下),材料的低速损伤主要是基体开裂;介于3 J到9 J之间的冲击作用下,基体开裂和分层是材料损伤的主要模式;冲击能量一旦超过9 J,材料中出现大量纤维断裂。

To study low velocity impact （LVI） damage of 2D C/SiC composite materials, a free-drop impact experiment was carried out. Non-destructive testing （NDT） techniques： acoustic emission （AE）, ultrasonic C-scan technique and scanning electron microscope were employed to monitor the experiment and detect the specimens after LVI. The results showed that： the impact energy resulted in the main damage modes of C/SiC composites under LVI load. Meanwhile, NDT could well characterize the damage of materials. When impact energy was lower, matrix cracking was the main damage mode; when impact energy was between 3 J and 9 J, matrix cracking and delamination were the main damage modes ; once impact energy exceeding 9 J, fiber fracture became the main damage mode.