Finite Element Analysis of Fretting Fatigue Using Different Pad‘s Geometries and Compression Forces

Abstract:

In this paper, a finite element sub-modelling method is used to estimate the stress distribution and the crack propagation lifetime in Aluminium alloy, Al7075-T6 specimens. Different contact geometries, i.e. cylinder-on-flat and flat-on-flat, and different contact span width’s with different pad’s compression forces are analysed. It is found that fretting fatigue life for two based cylindrical pads is shorter than that for two based flat pads and in two based flat pads is shorter than that for perfectly flat pads. In the case of two based flat pads, stress distribution in the pad with width of 3.1 mm is about 14% higher than that in the pad with the width of 6.2 mm and about 21% higher than that in the pad with the width of 9.3 mm. Similarly, stress in cylindrical pads with width of 3.1 mm is 36% higher than that in the pad with width of 6.2 mm and 130% higher than that in the pad with width of 9.3 mm. Stresses increased by 21% for pad force of 1800 N and around 40% for pad force 2400 N compared with 1200 N pad force. Also it is observed that by increasing pad width for both flat and cylindrical pads, crack propagation lifetime increased. Furthermore, fretting fatigue crack growth rate raises when pads compression force increases.

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