Study On Stress Singularity Field And Fretting Fatigue Life Of Fiber - Metal Plate Riveting

Fiber Metal Laminates joint components is widely used in industrial fields, especially in the aerospace field. Because riveted structures exist many contact interface, and the contact interface is easy to produce stress singularity and fretting fatigue failure under the action of external loads. Therefore, the analysis of Fiber Metal Laminates joint components interface stress singularity field and fretting fatigue have great significance to improve the riveting structural strength and reliability. This paper mainly contents of the following aspects:1) Base on the structural features of rivets, an eigenfunction expansion method is used to analyze stress singularities in the neigborhood of contact interfaces in cylindrical coordinates. At first, the expressions of the three-dimentional asymptotic stress and displacement fields in the vicinity of the circumferential line are estabhilsed. Then, a group of non-linear characteristic equations are established under various boundary conditions of an assembly with a rivet included in a bi-layer plate, based on which the orders of stress singularity, displacement and stress angular variation functions are determined. In the benchmark example, it is proved that eigenfunction expansion approach is valid for estimating the order of stress singularity in the cylindrical coordinates by comparing with the finite element method(FEM). In the numerical examples, the stress singularities in three-dimensional contact boundaries of riveted assemblies with flat, countersunk and universal head rivets are analyzed, and the effects of rivet materials, geometrical shapes and friction coeffients on the orders of stress singularities and stress angular variations are investigated.2) Through finite element software ABAQUS, taking Aluminum fiber laminates and steel sheet No. 45 joint components as research target, Obtained stress distribution on the fiber metal laminate layer and aluminum rivet contact interface. Then analysis of influences on the contact interface stress field by variation of cyclic loads、Rivet prestressed and interfacial friction coefficient.3) This paper describes critical plane method and the associated strain energy density criterion. Calculated damage parameter values on the contact interface,which between the aluminum layer of the fiber metal laminates and portion of the rivet cap, obtain the contours and the inner and outer edges of the distribution curve. Finally, it discussed the impact damage parameters on changing rivet prestressed state, cyclic loading and interfacial friction coefficient under ambient and cooling temperature.