A novel multiscale design method for porous structures with tunable anisotropy: Varied-shape Voronoi tessellation

Natural materials, through the multiscale architected organisms they contain, can evolve and control anisotropic properties to enhance their functionality and performance, thereby improving their adaptability to external environments. Similarly, recent studies have demonstrated engineered porous materials with multiscale architected structures and tunable anisotropy can achieve superior performance compared to commonly used isotropic porous materials. In this work, by locally tessellating varied-shaped Voronoi structures with modified Riemannian metric, we develop a novel bio-inspired design framework for multiscale porous structures, which can possess tunable orientation, porosity and anisotropic property. The effective mechanical properties of multiscale varied-shaped Voronoi tessellated (VSVT) porous structures are evaluated using a numerical homogenization technique, and finally expressed as a function of design parameters, i.e., anisotropy ratio, relative density, and material direction. A gradient-based, multi-scale, multi-component optimization workflow is applied to design and optimize porous materials and structures that mimic natural patterns. Typical design cases, such as Messerschmitt–Bölkow–Blohm beams with global or local volume constraints, have been carried out to verify the proposed VSVT method. The obtained geometry models from the de-homogenization procedure not only demonstrate high computational accuracy and improved compliance performance, but also exhibit flexible biofunctional compatibility like tailored specific surface area. This implies that the proposed VSVT design method for multiscale porous materials and structures have strong potentials for engineering applications, such as, implants, architecture, energy storage, and etc. •A multiscale porous material design method based on varied-shape Voronoi tessellation (VSVT) is proposed.•VSVT method enables the design of stochastic, multi-scale porous structures with tunable anisotropic and excellent connectivity.•Optimized VSVT porous materials with locally tailored anisotropy can achieve superior compliance performance compared to existing isotropic porous materials.•The optimized VSVT porous structures offers high flexibility in de-homogenization, allowing for adjustable local specific surface area.