Platon Seminar – Enora Denimal

Enora Denimal, Research Scientist at I4S (Inria Rennes).

Title: Surrogate modelling for structural design in nonlinear dynamics – application to friction damping in aircraft application.

In turbomachinery, bladed disks are a major component subjected to numerous vibration loadings at the origin of High Cycle Fatigue (HCF). As resonances cannot be avoided due to the high modal density, vibration levels at resonance must be mitigated. Using friction dampers between the blades is a well-spread technology today. One knows that the dynamic response is highly sensitive to the shape of such dampers, especially at the contact interface. However, due to the friction interface, the system becomes strongly nonlinear. It makes the nonlinear dynamic response computation complex and expensive requiring dedicated numerical solvers. So, the geometrical design of such components needs specific attention and dedicated numerical methods. Works that will be presented investigate how surrogate modelling can help to design the shape and the topology of such friction dampers for nonlinear resonance mitigation. First, a strategy coupling kriging to Nonlinear Modal Analysis demonstrates the interest of such a strategy for the shape design of friction ring dampers in bladed disks modelled with full 3D Finite Element Models. Second, it is demonstrated that topology optimisation can be carried out for nonlinear resonance mitigation thanks to surrogate modelling by coupling the EGO algorithm to the Harmonic Balance Method. Proof-of-concept on the 2D case will be shown.