Metamaterials in Structural Design

Significant low-frequency #vibration reduction is challenging with traditional damping technologies, and only a few #mechanical #metamaterials have shown potential. Our recent paper introduces shape-fusion functional and hierarchical metamaterials with negative mass effects, reducing vibration transmissibility by up to 80% in the 0–300 Hz range. Inspired by the Taichi (Taiji) Zhuyi diagram, these designs use a dual deep learning model with pre- and post-ANNs to optimise hierarchical metamaterials in honeycomb configurations. Interestingly, the ANN-optimised designs reveal topological similarities to ancient Taiji motifs and spiral/geometric artefacts from Ancient Greece, Rome, and the Han Dynasty, reflecting cultural exchanges along the Silk Road (100 BCE–250 CE). The paper provides experimental verification and analytical models that capture transmissibility and #bandgap metrics for designing general mechanical metamaterials. The link to the publication is here: https://lnkd.in/dUmchGnA. Happy to be involved as Dynamics & Control Research Group of the School of Civil, Aerospace and Design Engineering (CADE) - University of Bristol and Bristol Composites Institute in this work, led by the excellent Jianfei Yao and his team at Beijing University of Chemical Technology. As a side note, we have used in the Introduction of the paper the definition of metamaterial developed by the Metamaterials Network. I invite everyone in the community to adopt this definition, as it offers a more inclusive specification of what a #metamaterial is #adavncedmaterials #vibration #wavepropagation #ANN #deeplearning #design #3Dprinting #history #culture

MULTI-OBJECTIVE BAYESIAN OPTIMIZATION ALGORITHM FOR BEAM ELEMENT DESIGN OF CARBON NANOLATTICES Traditionally, materials engineers have spent years experimenting with various structures to optimize strength, weight, and durability, leading to the development of the strongest materials. By leveraging AI, researchers at the University of Toronto and Caltech analyzed countless possible nanostructures to create new nanoarchitected material, identifying designs that distributed stress while carrying heavy loads. Nanoarchitected materials have set new standards for non-monolithic mechanical performance, achieving the highest recorded specific strength, specific stiffness, and energy absorption characteristics. These exceptional properties result from the synergy of three factors: structurally efficient geometries tailored for loading conditions, high-performance constituent materials, and nanoscale size effects. These metamaterials hold significant potential to revolutionize design for lightweight structures in aerospace, ballistic absorption in defense, ultrafast response in optics and other contemporary applications. By utilizing a multi-objective Bayesian optimization (MBO) algorithm for beam element design, combined with high sp2 bonded nanoscale pyrolytic carbon, researchers created lightweight carbon nanolattices with ultra-high specific strengths and scalability. These nanolattices designed with the probability of hypervolume improvement (PHVI) algorithm offer remarkable structural efficiency, contributing to nanolattice ultrahigh specific strength and stiffness, as well as to constituent pyrolyzed carbon with nanoscale strut diameters. Specifically, the nanolattice metamaterial has ultrahigh specific strength of 2.03 MPa m³ kg−1 at lightweight densities, 118% enhancement in strength, and 68% improvement in Young's modulus. One of the biggest challenges in materials science is balancing strength and toughness that is critical for decrease of fuel consumption in airplanes, helicopters, and spacecraft, and durable to withstand the extreme stress. By replacing titanium components in airplanes with this new material, it could save up to 80 liters of fuel per year for every kilogram of material swapped. #https://lnkd.in/dcxAQA2y

🔬 Can metamaterials be stiff, tough, and extensible? 🧪 Inspired by tough hydrogels, we introduce double-network-inspired metamaterials to achieve this—along with a design, modeling & experimental framework to understand them! Out in Nature Materials today! 🔗 : https://lnkd.in/eq2-h2xu The concept revolves around intertwining monolithic lattices that serve as the stiff network, along with 3D woven architectures as the compliant network. Entanglements and self-contact then amplify plastic dissipation to large deformations. Through models that capture the kinematics and nonlinearities (both from the material and also due to contact and friction), we quantify the effect of the double network on frictional and plastic dissipation—we learn that entanglements are key! We demonstrate that the introduction of defects counterintuitively enhances toughness and stretchability in DNI metamaterials—reaching stretches of almost 4! The key is to avoid localized failure but instead distribute it throughout as much of the material as possible. Microscale fracture experiments, complemented by computational models, identify delocalized failure in the monolithic network to contribute to enhanced fracture energies. We learn that these toughening mechanisms draw analogies to real double-network hydrogels. Huge congrats to fantastic team member James Utama Surjadi for leading this effort from start to finish, and to Bastien F.G. Aymon and Molly A. Carton for key contributions throughout! The future is bright for compliant metamaterials! MIT Department of Mechanical Engineering (MechE)

NASA - National Aeronautics and Space Administration #scientists and #engineers presented a revolutionary #robotic structural system that embodies the concept of programmable matter, offering mechanical performance and scalability comparable to traditional high-performance materials and truss systems. The system utilizes fiber-reinforced composite truss-like building blocks to create robust lattice structures with exceptional strength, stiffness, and lightweight characteristics, functioning as mechanical metamaterials. This innovative approach is geared towards applications in adaptive #infrastructure, #space exploration, disaster response & beyond. The system's self-reconfiguring #autonomous design is underlined by experimental results, including a demonstration involving a 256-unit cell assembly and lattice mechanical testing. The assembled lattice material exhibits remarkable properties, boasting an ultralight mass density (0.0103 grams per cubic centimeter) coupled with high strength (11.38 kilopascals) and stiffness (1.1129 megapascals) for its weight. These characteristics position it as an ideal material for space structures. In structural testing, a 3x3x3 voxel assemblies could support more than 9000N. #robots #research: https://lnkd.in/dcS3XRC5 Future long-duration and deep-space exploration missions to the #Moon, #Mars, and #beyond will require a way to build large-scale infrastructure, such as solar power stations, communications towers, and habitats for crew. To sustain a long-term presence in deep space, NASA needs the capability to construct and maintain these systems in place, rather than sending large pre-assembled hardware from #Earth.