Development of a modelling and simulation framework to optimize layered bearing architectures

Plain half shell journal bearings are used in a wide range of turbomachinery shaft applications, including marine, automotive and power generation applications. These bearings have to be conformable and fatigue resistant under quite complex service loading conditions. Complex layered architectures may offer a tuneable approach to optimizing fatigue performance in terms of controlling initiation behavior and growth behavior (sometimes these two effects may play out in opposing ways). Currently a somewhat empirical approach is employed by manufacturers to identify the number, thickness and type of the different layers in the thin overlay coating. Work at Southampton University has now identified a consistent way in which to track the initiation and early stages of fatigue growth (using thermography techniques) and provided a detailed assessment of crack initiation and growth in the various layered constructions provided to date (using FIB and other advanced microscopy techniques). A follow-on PhD is now planned to apply these newly developed and validated techniques (mechanical testing, strain analysis, thermography and advanced microcopy characterization) to a systematic set of variations in overlay coating architecture (spacing, thickness, separation etc of hard and soft layers). These will be produced by the student via electroplating approaches at the sponsor company's new purpose built laboratory and they will then evaluate this systematic set of parametric explorations in terms of how this controls fatigue behavior. An important component of the PhD will be to develop and validate a materials modeling and simulation framework based on these findings to investigate optimization of the layered architecture for fatigue performance.