arXiv subjects

James Utama Surjadi

Publications and source records attributed to James Utama Surjadi.

3 recordsLinked to original sources

arXiv2026

Hierarchical Granular Metamaterials

Granular materials dissipate energy efficiently through intergranular interactions, yet their disordered, dense nature precludes precise control and integration into lightweight systems. Architected materials offer tunable mechanical responses at low densities but tend to localize stress, limiting dissipation efficiency. Here, we introduce hierarchical granular metamaterials that reconcile these trade-offs through three levels of design: lightweight architected grains engineered with hollow elliptical inclusions, crystal-inspired grain packings, and functional gradients and defects within grain tessellations. These metamaterials exhibit simultaneous increases in impact energy absorption per unit mass and reductions in transmitted peak force at low densities, outperforming conventional architected materials. In situ nanomechanical experiments and nonlinear computational models reveal that enhanced lateral grain expansion drives recruitment of neighboring grains, amplifying plastic and frictional dissipation. Multiscale impact experiments confirm that these mechanisms persist across length scales, constituent materials, and dimensionalities. Beyond mechanical performance, we demonstrate that spatially programmable inter-grain contact networks enable deterministic routing of deformation, which extends to electrical transport pathways independently of packing geometry. By combining granular principles with architected material design, this work establishes a paradigm for multifunctional metamaterials whose contact topology, mechanical response, and transport properties can be programmed independently.

cond-mat.soft↗

arXiv2025

Design framework for programmable three-dimensional woven metamaterials

Mechanical metamaterials have continued to offer unprecedented tunability in mechanical properties, but most designs to date have prioritized attaining high stiffness and strength while sacrificing deformability. The emergence of woven lattices-three-dimensional networks of entangled fibers-has introduced a pathway to the largely overlooked compliant and stretchable regime of metamaterials. However, the design and implementation of these complex architectures has remained a primarily manual process, restricting identification and validation of their full achievable design and property space. Here, we present a geometric design framework that encodes woven topology using a graph structure, enabling the creation of woven lattices with tunable architectures, functional gradients, and arbitrary heterogeneity. Through use of microscale in situ tension experiments and computational mechanics models, we reveal highly tunable anisotropic stiffness (varying by over an order of magnitude) and extreme stretchability (up to a stretch of four) within the design space produced by the framework. Moreover, we demonstrate the ability of woven metamaterials to exhibit programmable failure patterns by leveraging tunability in the design process. This framework provides a design and modeling toolbox to access this previously unattainable high-compliance regime of mechanical metamaterials, enabling programmable large-deformation, nonlinear responses.

cond-mat.soft↗

arXiv2024

Double-network-inspired mechanical metamaterials

Mechanical metamaterials are renowned for their ability to achieve high stiffness and strength at low densities, often at the expense of low ductility and stretchability-a persistent trade-off in materials. In contrast, materials such as double-network hydrogels feature interpenetrating compliant and stiff polymer networks, and exhibit unprecedented combinations of high stiffness and stretchability, resulting in exceptional toughness. Here, we present double-network-inspired (DNI) metamaterials by integrating monolithic truss (stiff) and woven (compliant) components into a metamaterial architecture, which achieve a tenfold increase in stiffness and stretchability compared to their pure woven and truss counterparts, respectively. Nonlinear computational mechanics models elucidate that enhanced energy dissipation in these DNI metamaterials stems from increased frictional dissipation due to entanglements between the two networks. Through introduction of internal defects, which typically degrade mechanical properties, we demonstrate an opposite effect of a threefold increase in energy dissipation for these metamaterials via failure delocalization. This work opens avenues for developing new classes of metamaterials in a high-compliance regime inspired by polymer network topologies.

cond-mat.soft↗