Re-programmable mechanical metamaterials for tunable energy dissipation through pre-stressing: Concept, mechanics and data-driven design

Nonlinear structures exhibiting negative stiffness have been harnessed as fundamental building blocks for reversible energy dissipation mechanical metamaterials through the utilisation of elastic instability. Traditional metamaterials suffer from a fixed energy dissipation performance once manufactured. We propose a novel approach using elastic tailoring, where the pre-stressing level within individual building blocks is adjusted by altering their boundary conditions. This innovative method allows for re-programming the energy dissipation performance in the post-manufacturing regime, offering unprecedented design flexibility and performance adaptability. We demonstrate this concept using shallow arches as building blocks, achieving elastic tailoring by manipulating the horizontal displacement of the supports. A parametric finite element (FE) model is developed in the commercial FE package Abaqus to analyse the nonlinear response of both the single building block and overall mechanical metamaterial sheet. Based on the numerical results, prototype metamaterial sheets with re-programmable energy dissipation are fabricated and experimentally tested. Excellent agreement is observed between the experimental results and numerical simulations. We demonstrate that the energy dissipation performance of the metamaterial can be increased by a magnitude via elastic tailoring Furthermore, we train a surrogate model based on neural network to map the geometry and pre-compression magnitude of the building block arch to the key performance indicators of the nonlinear equilibrium path. We have developed a performance-based inverse design framework that combines an optimization algorithm with the surrogate model. This tool enables the customization of individual building blocks to ensure that the overall metamaterial sheet meets the target performance. This work paves the way for the development of reprogrammable metamaterials through a simple and versatile elastic tailoring approach. • Exploits elastic tailoring for post-fabrication tuning of metamaterial energy dissipation. • Reprogrammable energy dissipation by adjusting pre-compression at support ends. • Energy dissipation can be increased by six fold using elastic tailoring in demos. • Fabricates and tests metamaterial sheets, demonstrating excellent agreement with simulations. • Integrates surrogate model and optimization in a performance-based design frame-work.