Effects of Thickness on Mechanical Properties of 2D C/SiC Torque Tube

Different failure modes and morphologies were found in the chemical vapor infiltration(CVI) 2D C/SiC torque tubes with different thickness. To characterize the density and porosity of the ceramic matrix composite(CMC) torque tube, a CT test was conducted. The archimedes drainage method was used to measure the density and porosity, and by adopting FEM software, the stress distribution and failure strength of the ceramic matrix composite torque tubes were calculated. A universal material test machine was used to implement torsional tests. Different torsional behaviors of CMC torque tubes with two different thicknesses were showed in the stress-strain curves. To analyze the predominant failure factors, SEM was used to observe the failure morphologies and cracks. 5 mm thickness CMC torque tube has reasonable fracture morphologies and a higher maximum shear strength and modulus.

C/SiC复合材料钻削工具载荷及磨损研究

采用HAM PCD焊刃麻花钻、KENNA CVD涂层麻花钻、金刚石套料钻(普通钻削与超声辅助钻削两种方法)三种工具对C/Si C复合材料进行了钻削试验,并对工具磨损情况、钻削力及扭矩进行了对比分析。结果表明:累计钻削深度lT=160mm后,套料钻普通钻削、超声辅助钻削磨损程度较轻,而HAM PCD焊刃麻花钻,KENNA CVD涂层麻花钻磨损严重。不同工具钻削加工时钻削力及扭矩随着工艺条件的变化呈现不同的变化趋势;采用套料钻加工时,与普通钻削相比,超声辅助钻削可有效降低钻削力及扭矩,最大降低幅度分别达到23%、56%。整体而言,套料钻超声辅助钻削加工时钻削力及扭矩较小、工具磨损较轻,是一种适合于C/Si C复合材料制孔的工艺方法。

一种典型C/SiC构型件的热噪声适应性试验研究

航天器结构用新型C/SiC复合材料在飞行过程中会承受气动加热和噪声复合环境,容易出现疲劳破坏,需要进行地面热噪声试验考核。针对一种典型的C/SiC蒙皮骨架构型件,利用行波管开展热噪声试验研究,对试验件、试验装置和试验方法等进行介绍。利用试验获得的有效数据揭示热噪声复合环境下该C/SiC构型件的失效模式,验证其热噪声环境适应性。