航空学报 > 2021, Vol. 42 Issue (5): 524250-524250   doi: 10.7527/S1000-6893.2020.24250

含多裂纹对接板应力强度因子三维有限元分析

冯振宇1,2, 柴崇博1,2, 邹君1,2, 牟浩蕾1,2   

  1. 1. 中国民航大学 适航学院, 天津 300300;
    2. 民航航空器适航审定技术重点实验室, 天津 300300
  • 收稿日期:2020-05-19 修回日期:2020-05-28 出版日期:2021-05-15 发布日期:2020-06-18
  • 通讯作者: 冯振宇 E-mail:mhfzy@163.com
  • 基金资助:
    航空科学基金(2017ZD67002)

Three-dimensional finite element analysis of stress intensity factors of butt-joints with multiple site damage

FENG Zhenyu1,2, CHAI Chongbo1,2, ZOU Jun1,2, MOU Haolei1,2   

  1. 1. College of Airworthiness, Civil Aviation University of China, Tianjin 300300, China;
    2. Key Laboratory of Civil Aircraft Airworthiness Technology, CAAC, Tianjin 300300, China
  • Received:2020-05-19 Revised:2020-05-28 Online:2021-05-15 Published:2020-06-18
  • Supported by:
    Aeronautical Science Foundation of China (2017ZD67002)

摘要: 应力强度因子(SIF)分析是含多部位损伤(MSD)结构的裂纹扩展分析及寿命预测的基础,对于连接结构采用简化模型难以考虑次弯曲、铆钉变形等因素影响。本文建立了含MSD对接板的三维有限元模型,研究了不同损伤模式、设计构型和约束条件下的裂纹尖端SIF分布特性以及随裂纹长度的变化规律。结果表明,孔边裂纹Ⅰ型SIF起主导作用,Ⅱ型和Ⅲ型SIF可忽略不计;由于次弯曲效应,SIF从外表面到内表面近似呈线性关系逐渐增加;MSD裂纹之间存在较强的干涉作用,且裂纹间距离越短数量越多,干涉作用越强;SIF随拼接板厚度增加呈先增加后降低的趋势,原因是拼接板刚度和铆钉柔度对铆钉载荷传递有一定影响;采用埋头铆钉会使SIF值增加,且内外表面差异变得更大;反翘曲约束对裂纹尖端SIF均值影响很小,但能显著降低SIF沿厚度方向的变化。

关键词: 多部位损伤(MSD), 对接结构, 应力强度因子(SIF), 三维有限元, 铆接

Abstract: Stress Intensity Factor (SIF) analysis is the basis for crack propagation analysis and fatigue life prediction of structures with Multiple Site Damage (MSD). It is difficult for joint structures based on simplified models to consider factors such as secondary bending and rivet deformation. In this paper, the three-dimensional finite element models of butt-joints with MSD are established, followed by analysis of the distribution and variation of SIFs at each crack tip with different damage modes, design configurations and constraint conditions. The results show that KI is dominant, while KII and KIII are negligible. Due to the secondary bending, the SIF increases approximately linearly from the outer surface to the inner surface. Strong interference exists between the MSD cracks, increasing the SIF, and the shorter the distance between the cracks, the stronger the interference. With the increase of the splice plate thickness, the SIF values increase first and then decrease because of the effect of the splice plate stiffness and the rivet flexibility on the load transfer ratio of the rivet. The value of SIFs with countersunk rivets is higher than that with flat head rivets, with an increased difference between the inner and outer surfaces. While the anti-bending constraint has little effect on the average value of the SIF at the crack tip, it can significantly reduce the variation of the SIF on the thickness direction.

Key words: multiple site damage (MSD), butt-joints, stress intensity factor (SIF), 3D finite element, riveted joints

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