Stress-driven method bio-inspired by long bone structure for mechanical part mass reduction by removing geometry at macro and cell-unit scales

[Display omitted] •Proposed mass reduction method is bio-inspired from long bones, from both medullar cavity and trabecular bone structures.•Test was carried out to compare the mechanical performances offered by the method with topology optimization at equal mass.•Presented 2.5D torsion disc mass was reduced by 60% compared to the initial disc.•Bio-inspired design of the sample is 27% stiffer, at equal mass, than the one obtained through topology optimization. Mass reduction is a main issue in mechanical design. Over millions of years, Nature had to face this issue. Nature came up with an efficient solution using a stress-driven structure to reduce the mass of bones while saving their mechanical performances. This optimized structure is used in several species and persists throughout Evolution. Thus, it may be considered as optimal for this issue. In this article, a method bio-inspired from both bone medullar cavity and trabecular structure is proposed to reduce the mass of parts subjected to mechanical stresses. The objective of this method is to provide high mass reduction, just like bone does. First, the method removes iteratively unloaded areas of material from the mechanical part to mimic the medullar cavity structure. Second, a final mass reduction is done integrating small holes bio-inspired from trabecular structure in the remaining material. An experimental validation was carried out on a torsion disc and provided a 60% mass reduction. Using this mass reduction rate, the topology optimization method was used to define a standard geometry to evaluate the mechanical performances of the proposed method. Experimental results highlight that regarding torsional stiffness, the bio-inspired part is 27% stiffer than the standard one.