From biological morphogenesis to engineering joint design: A bio-inspired algorithm

Abstract

Nature has developed smart strategies to morph joint contact surfaces as a response to local mechanical stimuli. Hence, it is compelling to explore the advantages of mimicking these strategies to design mechanical pieces. Researchers and engineers have developed generative design strategies mostly focused on structural topological and shape optimization. However, these generative strategies are not well developed for joint contact surfaces, even though they are critical points in engineering structures and machinery. This work presents a computational tool for adaptive surface shaping in contact problems inspired by the morphogenesis of synovial joints. The algorithm follows the cartilage growth rules, in which the hydrostatic and shear octahedral stresses either promote or inhibit an isotropic expansion of the local domain. The implementation is based on the finite element method and it is freely available on GitHub. A parametric study was performed to tune the parameters of the algorithm and it was successfully tested for two elastic bodies in unilateral contact. It was evidenced that the cartilage growth rules adapted the geometry of the surfaces in such a way that the contact stresses got uniformly distributed. This study is a step forward in the scope of bio-inspired generative designs.

Keywords

• Joint morphogenesis
• Bio-inspiration
• Elastic contact
• Surface shaping
• DoE