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1、南京航空航天大学 硕士学位论文 复合材料胶接修补金属裂纹板及其应力强度因子的研究 姓名：赵立涛 申请学位级别：硕士 专业：飞行器设计 指导教师：王志瑾 2010-12 南京航空航天大学硕士学位论文 I 摘 要 在飞机的服役期间，金属结构中会不可避免地出现各种损伤，其中最常见的损伤是疲劳裂 纹。为了延长飞机使用寿命，就必须要对损伤结构进行维修来提高结构的剩余强度，恢复其承 载能力。为了增强飞机的机动性和增加有效载荷及航程，应当尽量减轻飞机结构重量。与使用 金属补片进行修补相比，由于复合材料具有比刚度、比强度大、抗疲劳性能好、具有可设计性 等优点，所以通过复合材料胶接修补来加强裂纹结构更有优势。因
2、此复合材料胶接修补技术的 研究具有很高的实际应用价值。 本论文以含裂纹铝合金蒙皮的胶接修补为例，研究了复合材料胶接修补技术及应力强度因 子。论文的主要内容如下：(1) 通过有限元分析验证 COH3D8 单元模拟胶粘剂的可行性及准确 性；(2) 基于参数化建模技术建立了有限元模型，并分析比较了单面与双面修补后的应力强度 因子；(3) 以单面胶接复合材料为例，研究了复合材料补片及胶粘剂的相关参数对应力强度因 子的影响； (4) 通过 iSIGHT 与 ABAQUS 软件，利用遗传算法和序列二次规划法对 16 种不同厚 度的补片的铺层角度及几何尺寸进行了优化； (5) 通过对比 16 组优化结果确定
3、最佳的修补方案。 本论文中采用的分析方法及结果为实际应用提供了参考。 关键词：复合材料，胶接修补，参数化建模，应力强度因子，iSIGHT 复合材料胶接修补金属裂纹板及其应力强度因子的研究 II ABSTRACT During service of aircrafts, many kinds of damages inevitably appear in the metal structures and the most commom damage is fatigue crack. To extend the serve life of aging aircraft, cracked stru
4、ctures must be repaired to improve the residual strength and recover its carrying capacity. In order to enhance the flexibility and increase the effective load and voyage, the structural weight should be reduced as much as possible. Compared with the use of metal, bonded composite patches to reinfor
5、ce the cracked structure is more promising due to the high stiffness, high strength, good anti- fatigue performance and designability of the composite. Therefore, research on bonded composite patch repair technique will be of very high actual application value. In this thesis, taking cracked aluminu
6、m alloy skin repaired with bonded patch for example, the bonded composite patch repair technique as well as the stress intensity factor is studied. The main content of the article is as following: (1) The feasibility and accuracy of the method that adhesive is simulated by COH3D8 element is verified
7、 by using finite element analysis; (2) Finite element model is established based on parametric modeling technology, and the stress intensity factor of single- and douvle- sided repair is compared with each other; (3) Taking cracked plates repaired with single- sided composte patch for an example, th
8、e influence of the parameters of composite patch and adhesive on the stress intensity factor is researched; (4) The ply orientation of the stacking sequence as well as the size of sixteen kinds of patches with different thickness is optimized with Genetic Algorithms and Sequential Quadratic Programm
9、ing method by iSIGHT and ABAQUS. (5) Finally，the optimal repair scheme is determined after comparing the sixteen different optimization results. The analysis techniques and results in this thesis would provide reference for practical application. KeyWords: Composite materials, Bonded Repair, Paramet
10、ric Modeling, Stress Intensity Factor, iSIGHT 南京航空航天大学硕士学位论文 V 图表清单 图 1.1 飞机主要破坏形式分布图.2 图 1.2 歼八 I 型飞机的修理.2 图 1.3 复合材料胶接修补金属飞机结构的流程示意图.3 图 1.4 复合材料胶接修补技术的关键技术关系图.4 图 1.5 胶层受力状态.4 图 2.1 ABAQUS 对象模型 .10 图 2.2 修补几何模型及相关参数. 11 图 2.3 利用 Python 进行参数化建模得到的几何模型.16 图 3.1 胶层双搭接胶接验证模型.17 图 3.2 由简单“剪滞”理论得出的胶层剪切应力分布.18 图 3.3 胶层验证的有限元模型.18 图 3.4 胶层 Mises 应力图.19 图 3.5 胶层剪切应力 Syz.19 图 3.6 胶层剪切应力 Syz线性化曲线 .19 图 3.7 常见裂纹形式.20 图 3.8 三种常见的裂纹受载形式.21 图 3.9 胶接修补裂纹板有限元模型.23 图 3.10 裂纹尖端区域的 1/4 奇异单元.23 图 3.11 含中心裂纹铝板在未修补时沿 Y 方向的应力分布图.24 图 3.12 未修补裂纹板沿厚度方向的应力强度因子变化曲线.24 图 3.13 裂纹尖端应力强度因子理论公式值与有限元分
