配合条件对C/SiC在线铆接单元的力学性能影响  

Effect of fit conditions on mechanical properties of C/SiC online riveting unit

作　　者：谭志勇 王捷冰 孟繁夫 李彦斌[2] 钱逸星 刘小冲[4] TAN Zhiyong;WANG Jiebing;MENG Fanfu;LI Yanbin;QIAN Yixing;LIU Xiaochong(Science and Technology on Space Physical Laboratory,Beijing 100076,China;School of Mechanical Engineering,Southeast University,Nanjing 211189,China;School of Aeronautic Science and Engineering,Beihang University,Beijing 100191,China;School of Material,Northwestern Polytechnical University,Xi'an 710072,China)

机构地区：[1]空间物理重点实验室,北京100076 [2]东南大学机械工程学院,南京211189 [3]北京航空航天大学航空科学与工程学院,北京100191 [4]西北工业大学材料学院,西安710072

出　　处：《复合材料学报》2023年第7期4270-4281,共12页Acta Materiae Compositae Sinica

基　　金：国家自然科学基金(U20 B2002;52175220);国防技术基础科研项目(JSZL2019203 B003;2021-JCJQ-ZD-054-11);江苏省自然科学基金(BK20211558);东南大学“至善青年学者”支持计划(2242021 R41109)。

摘　　要：针对化学气相沉积(CVI)工艺2D C/SiC材料制备热结构中大量采用的在线铆钉连接形式及地面试验中表现出的特点,研究了铆钉与平板开孔之间采用间隙或过盈配合不同形式对力学性能的影响。制备了典型含铆钉单元试件并进行了细观形貌观测,通过铆钉顶出试验得到了不同配合条件下顶出静强度及疲劳规律;通过不同配合条件下含铆钉试件与开孔试件的拉伸静强度试验,获得了C/SiC在线铆接导致的面内连接强度性能下降的规律;描述了纤维束变形和材料局部区域破坏的特点,并依据形貌观测开展了数值计算验证。在此基础上,针对C/SiC过盈配合铆接形式提出了考虑孔边应力集中影响的改进点应力失效准则。结果表明:过盈配合可以改善铆钉与平板之间的连接可靠性,显著提高铆钉顶出静强度和疲劳强度,但过盈配合铆接的工艺过程使得孔边局部碳布纤维产生挤压偏折变形并导致了孔边预应力。According to the on-line rivet connection forms widely used in chemical vapor infiltration(CVI)process 2D-C/SiC thermal structures and characteristics shown in ground tests,the effects of different forms of clearance or interference fit between rivets and flat openings on mechanical properties were studied.A typical test piece with rivets was prepared and the microscopic morphology was observed.Through rivet push-out test,the push-out static strength and fatigue rules under different matching conditions were obtained.By comparing the tensile static strength of the specimens with rivets and the specimens with holes under different matching conditions,the rule of in-plane strength performance degradation caused by C/SiC online riveting was obtained.The characteristics of fiber bundle deformation,hole edge pre-stress and local area damage of materials were analyzed,and numerical modeling calculation was carried out according to morphology observation.Then,an improved point stress failure criterion(PSC)considering the effect of stress concentration at the hole edge was proposed for C/SiC interference fit riveting.Research shows that interference fit can improve the connection reliability between rivet and hole,significantly improve the push-out static strength and fatigue strength of rivet.But the interference fit riveting process makes the local carbon fiber at the hole edge extrude and deform,which leads to the prestress at the hole edge.

关 键 词：C/SIC 在线铆钉连接 强度性能 疲劳试验 配合条件 

分 类 号：TB332[一般工业技术—材料科学与工程] V414.8[航空宇航科学与技术—航空宇航推进理论与工程]