Micromechanics of deformation and abrasive wear of fiber-filled elastomers

Abstract

The abrasive wear of unfilled and fiber-filled elastomers was studied both with experiments and with finite element simulations. Wear experiments with elastomer seals exhibited two distinct regimes: an initial, "break-in" period followed by an "aggressive wear" period. During the break-in period, few abrasive particles are able to penetrate the seal's contact band, and no substantial seal wear occurs. During the aggressive wear period, abrasive particles aggregate into distinct clusters which advance at a linear rate and abrasively wear the seal. Filled elastomer seals were shown to have break-in periods significantly longer than those of unfilled elastomer seals. The aggressive wear rates and mechanisms of filled and unfilled elastomer seals were determined to be virtually identical. Abrasion patterns typical of the abrasive wear of elastomers were observed. Micromechanical modeling of the abrasive wear of unfilled elastomers predicted the formation of the observed abrasion patterns. Modeling of fiber-filled elastomers indicated that fibers should have no effect on the aggressive wear process. Additional modeling of fiber-filled elastomers suggested several mechanisms by which the fibers might extend the break-in period of the seal. Seal wear experiments with well-defined slurries offered strong evidence that the fibers extend the break-in period of the seal by inhibiting particle ingestion and cluster formation. A seal lip surface geometry is proposed to simulate the effect of the fibers.