玻璃纤维增强型复合材料圆筒高温高压动态冲击断口形貌分析

Fracture analysis of glass fiber reinforced composite material under high temperature and pressure

为了探究埋头弹火炮所用的玻璃纤维增强型(GFR)复合材料药筒在高温高压瞬态冲击条件下的结构强度,分别开展了圆筒静态整体拉伸和动态高温高压冲击实验,从拉伸/瞬态超高压破坏试样断口部分截取断口样品,在扫描电子显微镜下观察断口形貌,得到GFR复合材料在两种不同受力情况下的失效模式。结果表明:室温整体单轴拉伸断裂时,GFR复合材料的断面与轴线夹角接近45°,失效模式为环氧树脂基体破坏和纤维拔出;在高压瞬态冲击作用下,试样主要失效模式为纤维的脆性断裂,同时由于火药燃烧产生的高温燃气使部分环氧树脂基体碳化,纤维与基体界面结合力降低,少数纤维熔融或软化附着在断口上,部分软化的纤维因瞬态超高压被拉细。

In this study we carried out an static overall tensile experiment at room temperature and a transient blast experiment under ultra high pressure to investigate the structural strength of glass fiber reinforced（ GFR）composite cartridge of CTA gun with transient impulse under high temperature and pressure. The fracture surfaces of the specimens were cut from the tensile/transient ultra high pressure failure samples,and the fracture morphology was observed under the scanning electron micro scope. The results show that the main failure modes of GFR composites are matrix failure and fiber pulling-out when the uniaxial overall tensile fracture occurs at room temperature with the intersection between the GFR composites section and the axis close to 45°;the main failure mode of the specimen under transient ultra high pressure is the brittle fracture of the fiber and,due to the a portion of substrate’s carbonization resulting from the high temperature heat produced by the ignited gun powder,the fiber matrix interface’s binding force is reduced and a few fibers either melt or soften,becoming attached to the fractured surface,thereby attenuating part of the softened fibers due to the transient super high pressure.