Analysis On Mechanical Properties Of Glare Laminates Multi-bolt Joints

The GLARE(Glass Laminate Aluminum Reinforced Epoxy)laminate is a new type of fiber metal laminate(FML)which is heat-cured from aluminum alloy and glass fiber reinforced polymer.It has not only the advantages of specific stiffness,specific strength and designability of the composite,but also high ductility and good impact resistance of aluminum alloy,and has a wide range of applications in the aviation field.In large structural designs,the joint is an essential part,and the geometry of the joint affects its joint performance.A series of studies have been carried out on the mechanical joint structure design of composite laminates and metal sheets and the influence of geometrical dimensions on the distribution of multi-bolted joint loads.But for the joint of GLARE laminate composed of metal and composite materials,Research on load distribution is still insufficient.Therefore,it is very important to study the influence of geometrical dimensions of the joint structure on the load distribution of GLARE laminate.In this paper,the mechanical properties of GLARE laminate single-lap with a row of three-bolted joints under tensile load are analyzed by theoretical method,simulation method and experimental method.The influence of bolt-pitch(P)and bolt diameter(D)on its load distribution is studied.Firstly,the classical stiffness method and the spring model method are applied to calculate the load distribution of GLARE laminate three-bolted joints.The influence of different bolt-pitch and bolt diameter on load distribution is analyzed,which lays a theoretical foundation for subsequent research.Secondly,in order to verify the validity of the finite element model,the tensile test of GLARE laminate bolted joints is carried out,the load distribution of each bolt is calculated,and the influence of bolt pitch and bolt diameter on load distribution and structural load displacement curve are analyzed.Furthermore,the failure model of each component of GLARE laminates is established.The finite element simulation analysis of GLARE laminate three-bolted joints structure under tensile load is carried out by using ABAQUS software.The failure condition of the joint structure and the tensile load of the joint structure were analyzed.Under the tensile load response,the load distribution of each bolt in the elastic phase and the influence of bolt-pitch and bolt diameter on the load distribution are calculated.Finally,the load distribution and the influence law obtained by the theoretical method,the finite element simulation method and the test method are compared to obtain the bolt-pitch and bolt diameter which optimize the structural performance.The finite element model proposed in this paper can simulate the tensile properties of GLARE laminate single-lap multi-bolt joints structure,which provides a reference for the optimization design of GLARE laminates mechanical joint structure performance in the future aviation field.