Properties Analysis Of The Composites Liminates Bolted Joints

The joints of the composites materials have been an important problem along with the use of composite materials growing steadily. Among these joints, the bolted joint is a primary aspect of the mechanically fasted. The focus of this dissertation is the composite bolted joints. For the joints of composite materials, bolted joint design exerts strong influence on safety and reliability. So this dissertation focuses on the characters on the single-bolt, multi-bolt single-lap joint.The major content in this dissertation are as follows:Firstly, a comprehensive view on the current domestic and international developments of composite joints is taken. And then we show the main connection types. According the plan of BOJCAS (Bolt Joints in Composite Air Craft Structures) plan proposed by European Union and trend of related papers published in the latest years, the direction of this dissertation is raised. Secondly, the types of composite joints are introduced briefly and the damage modes, including the damage mechanism of composites materials and the methods to predict the damage are given. Then this dissertation provides contact problems in composites joints and describes the contact in finite element code ABAQUS in detail.Finally, the finite element model of single-bolt, multi-bolt and single-lap joints are established. The finite element simulation is built according to the different friction coefficient and assembly clearance. The results of the simulation are compared with the experiments results. It is proved that friction coefficient has significant influence on the distribution of bolt load. Especially, the friction coefficient of laminates give a most distinct influence on load distribution. Also, the different clearances affect on the distribution of the bolt load.