Topology optimisation of friction under-platform dampers using moving morphable components and the efficient global optimization algorithm

Abstract

Underplatform dampers (UPDs) are traditionally used in aircraft engines to reduce the risk of high cycle fatigue. By introducing friction in the system, vibrations at resonance are damped. However, UDPs are also the source of nonlinear behaviours making the analysis and the design of such components complex. The shape of such friction dampers has a substantial impact on the damping performances, topology optimisation is seldomly utilised -particularly for nonlinear structures. In the present work, we present a numerical approach to optimise the topology of friction dampers in order to minimise the vibration amplitude at a resonance peak. The proposed approach is based on the Moving Morphable Components framework to parametrise the damper topology, and the Efficient Global Optimisation algorithm is employed for the optimisation. The results demonstrate the relevance of such an approach for the optimisation of nonlinear vibrations in the presence of friction. New efficient damper geometries are identified in a few iterations of the algorithm, illustrating the efficiency of the approach. Results show that the most efficient geometry divides the vibration amplitude at resonance by 3, corresponds to a lower mass (80%) and a smaller frequency shift compared to the non-optimised case. More generally, the different geometries are analysed and tools for clustering are proposed. Different clusters are identified and compared. Thus, more general conclusions can be obtained. More specifically, the most efficient geometries correspond to geometries that reduce the mass of the damper and increase the length of the contact surface. Physically, it corresponds to a reduction of the initial normal contact pressure, which implies that the contact points enter stick/slip earlier, bringing more damping. The results show how topology optimisation can be employed for nonlinear vibrations to identify efficient layouts for components.

Topological Optimisation and 3d Printing of a Bladed Disc

“…The modal density of such components is high and all resonances cannot be avoided. It implies the control of the level of vibration et resonance with dedicated technologies such as friction dampers [5,6]. This work demonstrates the potential that topology optimisation can offer to the aircraft industry for the design of bladed discs considering structural and vibratory constraints.…”

“…the objective functions and constraints. More recent methods are based on evolutionary algorithms [5,6,11,12]. One main objective of this work is to see if current capabilities of current commercial software are enough to optimise the topology of a full bladed disc considering system resonances in rotating condition.…”

Multi-parametric optimization for controlling bifurcation structures

“…Grenat et al [38] implemented a recursive algorithm to compute the extrema of bifurcation curves in multi-parameter space for the design of a nonlinear tuned vibration absorber (NLTVA). Denimal et al [39,40] used topology optimization on under-platform dampers to reduce the amplitude at the resonance of a bladed disc. While all these methods are undoubtedly useful, they do not directly address bifurcations or only very specific types of bifurcations.…”

Numerical and Experimental Investigation of Friction Damping in Shrouded Blades

“…They only need limited number of dNNMs to build the surrogate model, thereby enabling rapid parameter optimization on the surrogate model. Denimal et al [36][37][38] further advanced this approach by combining the Kriging surrogate model with Generalized Polynomial Chaos (GPC). The combined surrogate model is adapted to calculate the complex engine value of nonlinear system with uncertain parameter characterized by interval or probabilistic.…”