Effect of clamping force on fretting fatigue behaviour of bolted assemblies: Case of couple steel–aluminium

One of the principal failures of bolting assemblies is the fretting. The combination of vibration and service load can introduce the damage of fretting fatigue on the contact surfaces of the assembly which lead at a nucleation of crack and then the structure fracture. Contact pressure or clamping force and displacement at the interface or relative slip are two important factors which control the fretting wear and the fretting fatigue. This paper describes the effect of clamping force (tightening torque) on the fretting fatigue behaviour of bolted assemblies. Both fretting fatigue experiments and simulation with FEM were carried out. With the increase of contact force, the sites of cracks initiation changed from the edge of the central hole to the free edge of the contact zone and the fretting fatigue life increase dramatically. A good correlation was found between the FEM simulations and the experimental results.