Numerical and experimental fretting fatigue with application to engineering design

Abstract

Fretting is a term covering a wide array of physical phenomena. When contacting bodies vibrate, relative slip between the bodies cause surface damage including wear and plasticity and cracks. Partially stuck contacts with high stress gradients produce micro-cracks at the surface which may propagate and cause fretting fatigue failure. Grossly sliding contacts, however, are often dominated by increasing wear and loss of material. Fretting have long been an interest to researchers in tribology and material sciences and continues to be a relevant phenomenon in engineering practice. Numerous theories and methodologies are applied to fretting problems, but engineering approaches are often simpler than those found in academia. In this thesis, fretting fatigue is investigated both numerically and experimentally with special attention to engineering applications. It is recognised that recent academic advancements in understanding and modelling capabilities represent opportunities for the practicing engineer facing fretting problems. In this thesis, traditional modelling using Finite Elements is used to solve fretting contacts. Critical plane post-processing is used to investigate fretting cracking behaviour. Some new experimental test rigs were developed to produce experimental results. Finally, simple, lumped-mass models were used to investigate friction dynamics related to fretting contacts.