Auxetic structures—a class of structural metamaterials with a negative Poisson’s ratio—are gaining popularity in energy absorption applications, including blast and impact protection. The counterintuitive deformation mechanism of auxetic structures enhances shear modulus and indentation resistance and improves energy absorption capacity, thereby offering a promising protective performance. Thus, advancements in auxetic structures can play a vital role in developing high-efficiency protective solutions for critical infrastructure to ensure the safety of the infrastructure and its occupants during extreme events. Therefore, we aim to develop novel lightweight, high-performance auxetic structures with a vision of their potential application in blast load mitigation.

We proposed a novel auxetic topology computational framework by using a density-based topology optimization method. The computational framework was applied to design novel lightweight, high-energy absorbing auxetic structures for protective applications. The designed auxetic structures were 3D printed using the fused filament fabrication technique. The potentialities of the novel auxetic structures in protective engineering applications were preliminarily assessed based on in-plane compression tests and a series of numerical analyses with validated computational models. The protective performances of the developed auxetic structures were further improved through a data-driven approach by coupling an automated numerical model, a neural network, and a genetic algorithm. Finally, the performances of the optimal and baseline designs of the novel auxetic structures were examined under a range of blast loads. Moreover, the blast mitigation performances of novel auxetic structures were compared with conventional auxetic structures.

This work contributed three novel lightweight, high-performance auxetic structures with unique counterintuitive deformation mechanisms. Quantified based on the peak elastic stress, plateau stress level, onset of densification strain, and energy absorption from in-plane compressions, novel auxetic structures outperformed conventional auxetic structures. Furthermore, novel auxetic structures showed superior protective efficacy under both close-in and far-field blast loadings. Overall, novel auxetic structures exhibited excellent features for shock mitigation and blast energy absorption applications.