Authors: Ferro Carlo, Grassi Roberto, Seclì Carlo, Maggiore Paolo


Publisher: Elsevier BV
Source: Procedia CIRP ; volume 41, page 1004-1010 ; ISSN 2212-8271
Terms of Re-use: CC-BY-NC-ND
Multi-rotors vehicles have become a consolidated reality in modern aeronautical field. These small helicopters consist in a fuselage “hanged” under a set of fixed pitch propellers each powered by an electric motor. These vehicles have great potentials and research in this topic is increasing aimed to reduce the structure weight to maximize flight time, range and payload.

Multi rotor components represent a key challenge for 3D modeling, optimization and additive manufacturing: they mainly consist in complex shapes where the most important feature are robustness and lightweight. Usually produced in small series, for example, eight parts for a single prototype, they almost need to be able to interface different materials.

The work here presented shows the advanced research conducted in cooperation between Altair Engineering and Politecnico di Torino to develop vital components for the structure of a multi-rotor: they represent a challenge because the main need is to interface arms, consisting in carbon fiber tubes, with motor or frame, both made in 7075 Alloy.

The use of topology optimization techniques plays a key role to minimize the weight of the components and to improve the productivity of the machines. Moreover, Additive manufacturing (FDM with Sharebot NG) allows producing more parts in less time improving the cost effectiveness of the project. The process will be described from a simple characterization of the anisotropic properties of 3-D printed specimens to FEM analysis of the preliminary design of the component and to the optimization phase performed with Altair Optistruct code.

An important role is played from the Altair tool used for the preliminary design: Inspire. This tool is conceived to generate structural efficient concepts quickly and easily to obtain lighter designs and eliminate structural design problems and finally provide input files for 3-D printers.

© 2015 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (


Illustration Photo: Multi-rotors drone (Public Domain from


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