The FEM Investigation Into The Composite Interference-fit Joints

Composite material has the advantages of high strength and high stiffness, so that they were widely implemented in the design of Aeronautics and Astronautics. With time goes by, there have been an enormous amount of advanced composite material implement for military aircraft. Mechanical joints are adequate for aeronautical composite materials, comparing with welding joints and hinge joints, mechanical joints are more reliable and have the advantages of the craft. Nowadays, the joints used in aircraft design are majorly mechanical joints, and the technique of interference fit joints has also been very well received.This project assignment are inspired from an investigation of the fatigue life of an interference fit joint on aluminum alloy. The assignment will be based on the commercial FEM software ANSYS to investigate the FE model which is built as composite interference fit joints. According to the mechanical characteristics of single bolted joints and multiple bolted joints, adding the consideration of the effect of the interference fit, the characteristic of composite fatigue life will be studied.First, the information of composite laminates and their mechanical joints are given, the basic information of the research in this category both foreign and domestic is generalized, and the substance of this thesis is introduced based on the information given before. The tangential stress from the edge of the composite laminate joints are analyzed. And the tangential stress from the edge of the joints under high and low two different kinds of remote loads are compared. And also, the effect of initial stress was brought to the analysis of the interference fit joints as well.Second, the information of multiple laminated joints and multiple interference fit joints are introduced, the comparison of single bolted joints and multiple bolted joints are compared, a reasonable result of the hole edge's stress contours was obtained. The status of the laminate joints'fatigue life was analyzed to obtain via the analysis of the stress contour caused by high and low remote loads over the multiple laminate joints.At last, all the information that were given and all the conclusion based on the analysis were summarized. And the observation of composite joints was made.