Topological Optimisation and 3d Printing of a Bladed Disc

Abstract

In turbomachinery, components are pushed to their limits to meet more stringent specifications in order to increase their performances. In this context, structural topology optimisation is a promising technology as it improves substantially the mechanical properties while drastically reducing the mass. With the coming of additive manufacturing, optimised geometry can be manufactured making this technology even more attractive. The aim of this work is to investigate the potential of topology optimisation to optimise a full bladed disc to improve its dynamic performances in terms of mass, stress and modal coincidences. The topology of a 3D-Finite Element Model of an academic bladed disc is optimised in this work and experimental validation is expected. So first, the disc is designed to fit in the test-rig and the mechanical integrity of the 3D-printed disc is experimentally verified. Second, the topology of the blades is optimised. Based on a trial-and-error process, the appropriate topology optimisation problem properties for vibration optimisation are identified. Thus, adding a static force at the blade tip forces a better material distribution over the domain and increases the blade stiffness. To minimise the number of coincidences, a numerical strategy based on iterative topology optimisation simulations is proposed to identify the correct set of frequential constraints. Final results show that the mass of the blade is reduced up to 32% and the number of frequential coincidences is reduced from 11 to 4. Final geometries are 3D-printed and mounted on the disc.