Effect of fit conditions on mechanical properties of C/SiC online riveting unit
-
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。Abstract: 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.
-
Key words:
- C/SiC /
- online rivet connection /
- strength character /
- fatigue test /
- fitting condition
-
图 2 C/SiC在线铆接部位在振动和强度试验中的破坏现象
Figure 2. Failure phenomenon of C/SiC online rivet connection part in vibration and strength test
图 3 典型铆钉单元试件的设计(a)及实物图(b)
Figure 3. Design (a) and physical drawings (b) of typical unit specimen with rivets
Φ—Diameter
图 4 C/SiC铆接局部的微型计算机断层扫描(µCT)图像
Figure 4. Partial computed tomography (µCT) images of C/SiC rivet specimen
图 5 C/SiC铆钉顶出强度试验的设计(a)及现场情况(b)
Figure 5. Design (a) and field situation (b) of C/SiC rivet push-out strength test
图 6 C/SiC试件的铆钉顶出静强度载荷-位移曲线对比
Figure 6. Comparison of static strength load-displacement curves of rivet push-out test pieces of C/SiC
图 7 C/SiC铆钉单元试件的顶出静强度破坏形貌对比
Figure 7. Comparison of push-out static strength failure morphology of C/SiC test units with rivets
图 8 C/SiC铆钉顶出疲劳强度试验测试结果及拟合曲线
Figure 8. Test results and fitting curves of rivet push-out fatigue strength test of C/SiC
图 9 C/SiC开孔试样的试验状态和拉伸破坏形态
Figure 9. Experimental state and tensile failure morphology of C/SiC specimen with opening-hole
图 10 C/SiC单独开孔及铆钉单元试件的拉伸测试性能比较
Figure 10. Comparison of tensile test performance between opening-hole and rivet-test units of C/SiC
图 11 C/SiC铆钉单元试件拉伸破坏形貌
Figure 11. Tensile failure morphology of C/SiC test units with rivets
图 12 C/SiC单独开孔与铆钉过盈装配试件的拉伸应力-应变曲线
Figure 12. Tensile stress-strain curves of samples with opening-hole and interference fitting test units with rivets of C/SiC
图 13 过盈装配C/SiC铆钉在静载荷顶出试验时的破坏局部特征
Figure 13. Local failure characteristics of interference-fitting C/SiC rivet in static push-out test
la—Width of the fiber bundle
图 14 铆钉过盈装配的几何关系以及纤维偏折/材料破坏的绕中心轴分布示意图
Figure 14. Geometry relation of rivet interference fit and fiber deflection/material failure distribution around central axis
d—Magnitude of interference; r—Distance from center of rivet hole; ra—Theoretical radius of rivet; θ—Angle with the direction of carbon cloth layer
图 15 不同厚度位置孔边纤维偏折计算及与实测对比
Figure 15. Calculation of fiber deflection at different thickness positions and comparison of measured results
图 16 采用虚拟纤维的铆钉装配数值建模
Figure 16. Numerical simulation of rivet assembly using virtual fiber
v—Deformation
图 17 采用虚拟碳纤维和SiC实体建模的铆钉装配模型
Figure 17. Rivet assembly model based on virtual carbon fiber and SiC solid
图 18 仅考虑虚拟纤维不同几何状态的C/SiC铆钉顶出计算结果
Figure 18. C/SiC rivet push-out calculation results only considering different geometric states of virtual fiber
图 19 铆钉过盈装配的C/SiC孔边预应力数值模拟结果
Figure 19. Numerical simulation results of pre-stress around hole in C/SiC rivet interference fitting model
S—Stress (Pa)
图 20 C/SiC开孔和含铆钉试样的孔边拉伸应力分布
Figure 20. Tensile stress distribution near hole edge of opening-hole and rivet fitting C/SiC specimen
W—Plate width; σθ—Circumferential stress; σr—Radial stress; σy—Tensile stress at the edge of the hole; da—Distance from hole edge
表 1 C/SiC材料及组分材料力学性能
Table 1. Mechanical properties of the C/SiC and component materials
Property Value Elastic modulus Ex(Ey) of C/SiC/GPa 115 Elastic modulus Ez of C/SiC/GPa 35 Poisson's ratio μxy of C/SiC 0.05 Poisson's ratio μxz(μyz) of C/SiC 0.01 Shear modulus Gxy of C/SiC/GPa 35 Shear modulus Gxz(Gyz) of C/SiC/GPa 32 Elastic modulus E1 of carbon fiber/GPa 124 Elastic modulus E2(E3) of carbon fiber/GPa 14 Shear modulus G23 of carbon fiber/GPa 18 Shear modulus G12(G13) of carbon fiber/GPa 20 Poisson's ratio μ12(μ13) of carbon fiber 0.17 Poisson's ratio μ23 of carbon fiber 0.01 Elastic modulus E of SiC matrix with voids/GPa 150 Shear modulus G of SiC matrix with voids/GPa 70 Poisson's ratio μ of SiC matrix with voids 0.08 
下载: 导出CSV
表 2 C/SiC单独开孔状态下的强度特征长度
Table 2. Strength characteristic length of C/SiC under the condition of opening
Hole radius
ra/mmTensile strength
σN/MPaσN/σ0 Characteristic
length da/mm0 212.0 1 — 1.0 186.0 0.877 1.38 1.75 159.3 0.751 1.32 2.0 152.0 0.717 1.32 2.75 136.1 0.642 1.39 Note: σ0—Tensile failure stress of no opening-hole.
下载: 导出CSV
-
[1] 韩国凯, 解维华, 孟松鹤, 等. 防隔热一体化复合材料整体性能优化设计方法[J]. 复合材料学报, 2019, 36(2): 450-460.HAN Guokai, XIE Weihua, MENG Songhe, et al, Optimization design method of integrated thermal protection/insulation composite material[J]. Acta Materiae Compositae Sinica, 2019, 36(2): 450-460(in Chinese). [2] 张立同. 纤维增韧碳化硅陶瓷复合材料: 模拟、表征与设计[M]. 北京: 化学工业出版社, 2009.ZHANG Litong. Fiber-reinforced silicon carbide ceramic composites: Modelling, characterization and design[M]. Beijing: Chemical Industry Press, 2009(in Chinese). [3] 孟松鹤, 杨强, 霍施宇, 等. 一体化热防护技术现状和发展趋势[J]. 宇航学报, 2013, 34(10):1295-1302. doi: 10.3873/j.issn.1000-1328.2013.10.001MENG Songhe, YANG Qiang, HUO Shiyu, et al. State-of-arts and trend of integrated thermal protection systems[J]. Journal of Astronautics,2013,34(10):1295-1302(in Chinese). doi: 10.3873/j.issn.1000-1328.2013.10.001 [4] ZHANG Q M, LI G S. A review of the application of C/SiC composite in thermal protection system[J]. Multidiscipline Modeling in Materials and Structures,2009,5(2):199-203. doi: 10.1163/157361109787959903 [5] HUDSON L D, STEPHENS C A. X-37 C/SiC ruddervator subcomponent test program[C]//NASA 2009 Annual Meeting. Houston: NASA, 2009. [6] 杜善义. 先进复合材料与航空航天[J]. 复合材料学报, 2007, 24(1):1-11. doi: 10.3321/j.issn:1000-3851.2007.01.001DU Shanyi. Advanced composite materials and aerospace engineering[J]. Acta Materiae Compositae Sinica,2007,24(1):1-11(in Chinese). doi: 10.3321/j.issn:1000-3851.2007.01.001 [7] ZOU P, CHEN X M, CHEN H, et al. Damage propagation and strength prediction of a single-lap interference-fit laminate structure[J]. Frontiers of Mechanical Engineering,2020,15(4):558-570. doi: 10.1007/s11465-020-0591-5 [8] 邹鹏, 曲凡. 复合材料衬套螺栓干涉连接安装过程损伤机制[J]. 复合材料学报, 2022, 39(5):2449-2459. doi: 10.13801/j.cnki.fhclxb.20210616.007ZOU Peng, QU Fan. Damage mechanism of composite sleeve-type bolt interference fit structure during the installation process[J]. Acta Materiae Compositae Sinica,2022,39(5):2449-2459(in Chinese). doi: 10.13801/j.cnki.fhclxb.20210616.007 [9] 宋祚禹, 王西昌, 曹正华, 等. 碳纤维/聚脂亚胺树脂基复合材料开孔件的连接力学性能[J]. 航空制造技术, 2009(z1):139-140, 144. doi: 10.3969/j.issn.1671-833X.2009.z1.043SONG Zuoyu, WANG Xichang, CAO Zhenghua, et al. Joint mechanical properties of open-hole carbon fiber reinforced polyimide composites[J]. Aeronautical Manufacturing Technology,2009(z1):139-140, 144(in Chinese). doi: 10.3969/j.issn.1671-833X.2009.z1.043 [10] 赵丽滨, 徐吉峰. 先进复合材料连接结构分析方法[M]. 北京: 北京航空航天大学出版社, 2015.ZHAO Libin, XU Jifeng. Analysis method for advanced composite joints[M]. Beijing: Beihang University Press, 2015(in Chinese). [11] 张毅. CVI-2D C/SiC复合材料铆接单元的力学行为与失效机制[D]. 西安: 西北工业大学, 2017.ZHANG Yi. Mechanical behaviors and failure mechanisms of z-pinned joints for 2D C/SiC composite prepared by chemical vapor infiltration[D]. Xi'an: Northwestern Polytechnical University, 2017(in Chinese). [12] ZHANG Y, ZHANG L T, HE J Y, et al. Modelling shear behaviors of 2D C/SiC Z-pinned joint prepared by chemical vapor infiltration[J]. Ceramics International,2018,44(6):6433-6442. doi: 10.1016/j.ceramint.2018.01.038 [13] LEONE F A, DAVILA C G, CIROLAMO D G. Progressive damage analysis as a design tool for composite bonded joints[J]. Composites Part B: Engineering,2015,77:474-483. doi: 10.1016/j.compositesb.2015.03.046 [14] LI G D, WU X F, ZHANG C R, et al. Theoretical simulation and experimental verification of C/SiC joints with pins or bolts[J]. Materials & Design,2014,53:1071-1076. [15] HE Z B, ZHANG L T, ZHANG Y, et al. Microstructural characterization and failure analysis of 2D C/SiC two-layer beam with pin-bonded hybrid joints[J]. International Journal of Adhesion and Adhesives,2015,57:70-78. doi: 10.1016/j.ijadhadh.2014.10.008 [16] ZHANG X Y, SUO T, WANG B, et al. Fatigue behavior and residual strength evolution of 2D C/SiC Z-pinned joints prepared by chemical vapour infiltration[J]. Journal of the European Ceramic Society,2019,39:3575-3582. doi: 10.1016/j.jeurceramsoc.2019.04.051 [17] ZOU P, ZHANG K F, LI Y, et al. Bearing strength and failure analysis on the interference-fit double shear-lap pin-loaded composite[J]. International Journal of Damage Mechanics,2016,27(2):179-200. [18] ZOU P, LI Y, ZHANG K F, et al. Mode I delamination mechanism analysis on CFRP interference-fit during the installation process[J]. Materials & Design,2017,116:268-277. doi: 10.1016/j.matdes.2016.11.063 [19] LI Y, XIAO P, LUO H, et al. Fatigue behavior and residual strength evolution of 2.5D C/C-SiC composites[J]. Journal of the European Ceramic Society,2016,36(16):3977-3985. doi: 10.1016/j.jeurceramsoc.2016.07.009 [20] 杨晔楠, 赵美英, 周银华. 过盈配合对复合材料多钉连接强度的影响研究[J]. 航空工程进展, 2012, 3(3):311-316. doi: 10.3969/j.issn.1674-8190.2012.03.012YANG Yenan, ZHAO Meiying, ZHOU Yinhua. Study on effect of interference fit on joint strength for multi-fasteners in composites[J]. Advances in Aeronautical Science and Engineering,2012,3(3):311-316(in Chinese). doi: 10.3969/j.issn.1674-8190.2012.03.012 [21] 邹鹏. 复合材料干涉螺接结构损伤萌生与扩展机理研究[D]. 西安: 西北工业大学, 2017.ZOU Peng. Research on the damage initiation and evolution mechanism of composite interference-fit bolted structures[D]. Xi'an: Northwestern Polytechnical University, 2017(in Chinese). [22] HWAN C L, TSAI K H, CHEN W L, et al. Strength prediction of braided composite plates with a center hole[J]. Journal of Composite Materials,2011,45(19):1991-2002. doi: 10.1177/0021998311399483 [23] TAN Z Y, DONG W L, MEI J, et al. Strength and mechanical response of C/C composite open-hole and bolted plates[J]. Materials Testing,2017,59(9):774-778. doi: 10.3139/120.111067 -
下载:
点击查看大图
计量
- 文章访问数: 560
- HTML全文浏览量: 302
- PDF下载量: 44
- 被引次数: 0
