Numerical and experimental investigation of bump foil mechanical behaviour

• Nonlinear finite element model for analysing dynamic behaviour of bump foil strip.
• Theoretical hysteresis loops in contact points under stick and slip conditions.
• Experimental setup using parallel surfaces for testing of corrugated structures.
• Experimental hysteresis loops in corrugated structures and frequency dependencies.

Corrugated foils are utilised in air foil bearings to introduce compliance and damping thus accurate mathematical predictions are important. A corrugated foil behaviour is investigated experimentally as well as theoretically. The experimental investigation is performed by compressing the foil, between two parallel surfaces, both statically and dynamically to obtain hysteresis curves. The theoretical analysis is based on a two dimensional quasi static FE model, including geometrical non-linearities and Coulomb friction in the contact points and neglects the foil mass. A method for implementing the friction is suggested. Hysteresis curves obtained via the FE model are compared to the experimental results obtained. Good agreement is observed in the low frequency range and discrepancies for higher frequencies are thoroughly discussed.