摘要
复合材料双钉连接结构的复材孔周由于载荷分布不均、应力状态复杂而易于损伤破坏,开孔区域通常是连接结构的薄弱环节,飞机结构维修时一般将连接孔圆整为标准尺寸来恢复其结构强度,对此研究双钉扩孔维修后的载荷分布规律及影响因素,对结构部件保证适航性和提高连接效率具有重要意义。本文以复合材料/铝合金连接结构为研究对象,通过ABAQUS软件建立了嵌入Hashin失效判据和改进Camanho刚度折减系数的双钉单剪连接三维渐进损伤分析模型,并进行了试验验证,着重分析了不同维修孔径组合对双钉单剪连接的拉伸静强度及损伤的影响。结果表明,有限元分析得到的载荷-位移曲线和失效模式与试验结果基本吻合,最大误差为8.9%;靠近加载端的螺栓D_(2)的载荷高于靠近金属板固定端的螺栓D_(1);按标准连接参数增大D_(2)直径(W/D_(2)减小)可以改善双钉连接孔边应力集中,提高初始强度和极限强度,过大的D_(2)直径会减小复材板的净横截面积,导致连接强度下降;摩擦系数增大会延缓复材板初始损伤的发生,导致整体刚度衰减显著延缓。
The composite hole circumference of the composite double-bolt joints structure is easy to be damaged due to uneven loading and complex stress state.The penetrate area is usually the weak link of the connection structure.The connecting hole is generally reamed to a standard size circle during aircraft structural maintenance.Thus it is of great significance to study the rules of corresponding distribution and factors of hole influencing after double-pin reaming maintenance.This is of great significance to ensure the airworthiness of structural components and improve the connection performance.This paper took the composite material/aluminum alloy connection structure as the research object,and built a three-dimensional progressive damage analysis model of double-bolt single-shear connection with embedded Hashin failure criterion and improved camanho stiffness reduction coefficient through the ABAQUS software.The experimental verification was carried out,and it was emphatic on the effect of combinations on the tensile static strength and damage in double-nail single-shear connections with different maintenance aperture.The results show that the load-displacement curve and failure mode obtained by the finite element analysis are basically consistent with the test results,with a maximum error of 8.9%.The bolt load of D_(2) near the loading end is higher than that of the bolt D_(1) near the fixed end of the metal plate.The D_(2) diameter increased(W/D_(2) decrease)with the standard connection parameters can improve the stress concentration at the edge of the double-bolted connection hole,and increase the initial and ultimate strength.But excessive D_(2) diameter will reduce the net cross-sectional area of the composite sheet,resulting in a decrease in joint strength.The increase of the friction coefficient will prolong the occurrence of the initial damage of the composite plate,resulting in a significant delay in the attenuation of stiffness.
作者
刘峰
周建国
陈威杨
闫清云
LIU Feng;ZHOU Jianguo;CHEN Weiyang;YAN Qingyun(Aviation Engineering Institute,Civil Aviation Flight University of China,Guanghan 618307)
出处
《宇航材料工艺》
CAS
CSCD
北大核心
2022年第3期94-102,共9页
Aerospace Materials & Technology
基金
民航局科技创新引导资金项目(14002600100017J171)
中国民用航空飞行学院研究生创新项目(X2020-08)
中央高校基本科研业务费基金项目(J2022-026)。
关键词
复合材料
维修扩孔
强度
层合板
双钉连接
Composite material
Maintenance reaming
Strength
Laminates
Double-bolted joint
