Modélisation plastique bi-linéaire de l'usure de matériaux abradables: application aux turbo-machines

Abstract

A simplified macroscopic implementation of abradable material wear in aircraft engines is introduced. These coatings are located along the circumference of the surrounding casings facing the blade-tips. More specifically, it is intended to numerically embed the abradable profile changes within an explicit time-stepping technique dedicated to blade-to-casing interactions by means of unilateral contact. This profile is updated through the use of a plastic constitutive law for the evolution of the abradable material. In order to keep low computational efforts allowing for parameter studies, a reduced order model of the blade of interest is built by following the Craig-Bampton modal synthesis technique. This choice is motivated because it offers the possibility to treat the contact constraints and wear conditions directly in the reduced-order space. It is shown that the mechanical behavior of the abradable material may initiate dangerous divergent motions of the blade. Under specific conditions, the use of abradable coatings should be avoided.