Vibration analysis of nonsmooth structural systems

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The objective of this research is to provide improved understanding, modeling, and prediction of the vibration response of complex possibly structural systems. This will be accomplished by developing innovative numerical methods capable of tackling the growing complexity of dynamical phenomena resulting from optimized designs and severe operational environments. Bladed disk systems found in aircraft and helicopter engines will serve as the preferred industrial applications of this analytical and computational program. Meticulous attention will paid to the numerical treatment of the vibrations of systems involving nonsmooth interface quantities, i.e. unilateral contact and friction conditions. Other modeling complexities will include large model size and time-delayed phenomena. To this end, the proposed Discovery Grant application will focus on two major thrusts: 1. The first thrust will be the development of efficient numerical techniques dedicated to the Nonsmooth Modal Analysis of generic simple structures and geometries. Modern numerical formulations embedding discontinuous quantities will be preferred for the reliable treatment of complex interfaces and will open avenues for a systematic exploration of a broader range of nonsmooth phenomena. 2. The second thrust will concern the high-fidelity modeling and analysis of full rotating structures that should be dealt with as a whole. Reduced-order models of full multistage bladed-disk assemblies with respective nonsmooth supporting devices and surrounding flexible casings will be constructed. This also implies the optimization in a modal sense of existing structural designs so that they become more compliant and tolerant to unilateral contact and friction conditions as well as the possibility of relaxed manufacturing tolerances within stochastic analyses.