Bio-inspired generative design of contact interfaces subjected to time-dependent loading conditions

In both biological and human-made mechanical systems, contact interfaces play a crucial role in transferring power. Although their lifespan is enhanced by uniform contact pressure distribution, designing shapes achieving this remains challenging, especially under time-dependent loads. Contrarily, synovial joints are adapted to withstand severe and time-dependent loads. This adaptation is driven by two key principles: shear stress promotes ossification, while hydrostatic pressure promotes proliferation. This study analyses the response of a generative design algorithm for contact problems based on these principles embedded into a growth rule. By varying material stiffness, initial conditions, and loading scenarios, the algorithm successfully adapts contact interfaces for both time-independent and time-dependent loads. The results demonstrate that the growth principles lead to almost uniform contact pressure under time-independent loads, up to 34.7% more uniform than reference shapes. Under time-dependent loads, it generates shapes with reduced maximum shear stress and contact pressure (up to 73%) with respect to initial shapes. Unlike other methods, such as optimisation techniques, this approach does not seek a specific contact interface where pressure is well-distributed. Instead, the development of well-distributed pressure is an intrinsic part of the growth function. Hence, the algorithm provides a family of contact interfaces exhibiting uniform contact pressure whose shape depends on the development time. Additionally, the growth rule is easier to compute than gradients for gradient-based optimisation, and, in contrast to heuristic optimisation techniques, only one direction of change is necessary. Thus, this bio-inspired approach provides a viable alternative for shape optimisation problems in contact mechanics.