摘要
对面外钉载作用下纤维金属层合板螺接结构拉脱失效机理进行了研究,考查了纤维铺层方向和金属体积分数对其拉脱性能的影响。基于应变形式的Hashin失效准则、金属延性断裂准则及层间内聚力本构模型,建立了复合材料连接结构三维渐进失效模型。通过有限元仿真方法,预测了螺接结构的拉脱强度,并基于试验验证了数值模型的可靠性。研究结果表明,拉脱载荷作用下,复合材料开孔区域逐渐呈锥形隆起,最终螺栓嵌入纤维金属层合板导致螺接结构承载失效,拉脱失效特征与冲击破坏相似。铝锂合金的压溃破坏及纤维金属界面的层间分离是结构拉脱破坏的主要机理。螺接结构刚度折减至亚临界损伤值后,受材料压缩效应,刚度出现二次升高趋势。纤维沿±45°方向对称铺层下的纤维金属层合板正交性最高,拉脱强度最大。螺接结构拉脱极限载荷与金属体积分数成正比。
The pull-out failure mechanism of fiber-reinforced metal laminate(FML)bolted structure under external nailing load was studied.The effects of fiber ply direction and metal volume fraction on the pull-out performance were investigated.Based on the Hashin failure criterion of strain form,the ductile fracture criterion of metal and the constitutive model of interlayer cohesion,a three-dimensional progressive failure model of composite connection structure was established.Through the finite element simulation method,the pull-out strength of the bolted structure was predicted,and the reliability of the numerical model was verified based on the test.The results show that under the pull-out load,the opening area of the composite material gradually presents a cone-shaped uplift,and finally the bolt embedded into the fiber metal laminate leads to the bearing failure of the bolted structure,and the pull-out failure characteristics are similar to the impact failure.The collapse failure of Al Li alloy and the interlayer separation of fiber metal interface are the main mechanisms of pull-out failure.After the stiffness of the bolted structure is reduced to the subcritical damage value,the stiffness increases twice due to the material compression effect.The results show that the orthogonality and pull-out strength of fiber metal laminates with symmetrical fiber ply along±45°direction are the highest.The pull-out limit load of bolted structure is proportional to the volume fraction of metal.
作者
刘衍峰
张达
周振功
高志良
Liu Yanfeng;Zhang Da;Zhou Zhengong;Gao zhiliang(Changchun Institute of Optics,Fine Mechanics and Physics,Chinese Academy of Sciences,Changchun 130033,China;Institute of Composites and Structures,Harbin Institute of Technology,Harbin 150001,China)
出处
《机电工程技术》
2020年第8期44-49,共6页
Mechanical & Electrical Engineering Technology
关键词
功能梯度复合材料
螺栓连接
渐进失效
拉脱破坏
functional gradient composites
bolted joint
progressive failure
pull-through failure
