| Summary: | This study aims to understand the mechanism of elastomer abrasion using Finite Element Analysis (FEA) techniques. A blade abrasion device is used to create the abrasion patterns. The initiation of the abrasion patterns is investigated by observing how the cracks develop on the moulded flat elastomer surface. At first, cracks initiate at the location of the maximum tensile stress, yielding a crack growth angle of between 30o~50° with the elastomer surface. The angle being greater as the normal load applied on the blade is increased. The crack growth angle reduces as the crack increases in length. It passes through several steps, each with a reduced crack growth angle and eventually reaches a much smaller angle generally observed at the steady state of abrasion. This initial crack growth process is predicted well by the FEA simulation. Both the experimental and the computed results suggest that the initial cracks in elastomer abrasion originate from micro-vibrations generated during the slip phase of stick-slip motion. This stick-slip motion is regularly encountered during the frictional contact between a soft elastomer and hard abrader. The propagation of the abrasion patterns after reaching steady state is also investigated using a blade abrasion device. The second part of this investigation examines the effect of the normal and frictional forces on the rate and direction of crack growth during the abrasion process. Comparison is drawn between the rates of material loss as measured experimentally under a range of test conditions and the predictions calculated using a fracture mechanics based FEA. For the first time here it is shown that an explicit dynamic FEA model can be used to reliably predict the stored energy release rate in a complicated large strain contact model. A series of different finite element models were developed to investigate the tearing processes at a specific asperity under each revolution or pass of the abrasion blade. These models predict for SBR materials the rate of the resulting tearing processes well.
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