Abstract
In this paper, experimental and finite element methods are considered for analysis of the influence of contact pressure on fretting fatigue behavior of Al-Zn-Mg alloy. Based on the fretting fatigue test apparatus with point contact, a two-dimensional implementation within the finite element software ANSYS is investigated to analyze stress distribution. A series of experimental tests are carried out so that the effect of contact pressure on the fretting fatigue characteristics and fretting fatigue life is emphatically researched. Fretting regions morphology and fretting fatigue fracture behavior have analyzed the action of fatigue and wear to determine slip amplitude effects in the fretting process in which contact pressure and tangential force are revealed as important parameters to determine crack initiation, propagation, and damage mechanisms. The calculation results indicate that for tension/compression fretting fatigue, there is a sticking region, sliding region, and opening region on the contact surface with contact pressure changing while other test parameters are invariable. When the stress amplitude is 252 MPa, with the increase of contact pressure, the cycles of cyclic softening under tension/compression fretting fatigue loading decrease, and fretting fatigue life decreases with the increase of contact pressure, which is lower than fatigue life under the same tension/compression fatigue loading. The numerical simulation reveals the merits of applying the finite element method to fretting fatigue problems, and it shows good agreement with experimental results.

Key words
Al-Zn-Mg alloy, fretting fatigue, contact pressure, point contact, ANSYS

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