复合材料科学与工程 ›› 2021, Vol. 0 ›› Issue (11): 12-20.DOI: 10.19936/j.cnki.2096-8000.20211128.002

• 基础研究 • 上一篇    下一篇

碳纤维增强复合材料沉头螺栓搭接结构强度及渐进损伤分析

余芬, 刘国峰, 何振鹏, 黎柏春*   

  1. 中国民航大学 航空工程学院,天津300300
  • 收稿日期:2021-03-10 出版日期:2021-11-28 发布日期:2021-12-13
  • 通讯作者: 黎柏春(1986-),男,博士,主要从事机械结构强度及复合材料失效方面的研究,bc_li@cauc.edu.cn。
  • 作者简介:余芬(1963-),女,教授,主要从事航空复合材料制造与修理方面的研究。
  • 基金资助:
    天津市自然科学基金项目(18JCQNJC05400);天津市教委自然科学项目(2018KJ240);中央高校基金(3122019075);中国民航大学实验技术创新基金(2020CXJJ157)

Analysis of structural strength and progressive damage of countersunk bolt lap joint with CFRP

YU Fen, LIU Guo-feng, HE Zhen-peng, LI Bai-chun*   

  1. Aeronautical Engineering Institute, Civil Aviation University of China, Tianjin 300300, China
  • Received:2021-03-10 Online:2021-11-28 Published:2021-12-13

摘要: 碳纤维增强复合材料(CFRP)因其优异的力学性能在航空工业中得到了广泛的应用,评估复合材料沉头螺栓连接结构的极限承载和损伤扩展对航空器连接结构的经济性和安全性意义重大。本文首先创建复合材料沉头螺栓搭接三维模型,并采用虚拟热变形法施加螺栓预紧力,然后利用Fortran语言编写VUMAT用户自定义程序,将所选的刚度退化模式与3D Hashin失效准则嵌入渐进损伤模型中,建立有限元损伤预测模型,研究不同搭接端距对复合材料沉头螺栓连接结构失效的影响。研究结果表明:搭接端距主要影响连接结构的剪切强度,端距越小,其极限承载强度越小,当搭接端径比达到2.5时,极限承载强度随着端径比的增大变化较小;基体拉伸损伤首先出现在最底层的0°铺层,纤维压缩损伤首先出现在锪孔和直孔转折处,失效单元沿施载方向扩展至自由边界失效。

关键词: 复合材料, 沉头螺栓连接, VUMAT, 三维Hashin失效准则, 渐进损伤模型

Abstract: Carbon fiber reinforced polymer (CFRP) has been widely used in aviation industry due to its excellent mechanical properties. It is of great significance to evaluate the ultimate load and damage propagation of composite countersunk head bolt joints for the economy and safety of aircraft joints. In this paper, a three-dimensional model of composite countersunk head bolt lapping is established, and the pre-tightening force of the bolt is applied by virtual thermal deformation method, then the VUMAT user-defined program is written in FORTRAN language though finite element simulation. The selected stiffness degradation mode and 3D Hashin failure criterion are embedded into the progressive damage model to establish the finite element damage prediction model, and study different lap end distance on the composite material single screw countersunk bolt connection structure failure. The results show that the lap end distance mainly affects the shear strength of the connection structure. The smaller the end distance is, the smaller the ultimate bearing strength is. When the short diameter ratio of the lap joint reaches 2.5, the ultimate bearing strength changes little with the increase of the end diameter ratio. The tensile damage of the matrix first appears in the 0° ply of the bottom layer, the fiber compression damage first appears in the turning point of the countersink and straight hole, and the failure element expands along the loading direction until the free boundary fails.

Key words: composite materials, countersunk bolt connection, VUMAT, three-dimensional Hashin failure criterion, progressive damage model

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