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Item type:Publication, Access status: with files , LLM-driven design of physics-constrained constitutive models: Two agents are better than one(Springer, 2026-10-01); ; ; ; Developing constitutive models that capture how materials deform under load traditionally requires years of specialized expertise in continuum mechanics, machine learning, and scientific programming. Large language models (LLMs) have recently been shown to lower this barrier by generating constitutive models on demand, but existing single-agent pipelines lack systematic checks that the resulting models respect fundamental physical laws. To close this gap, we introduce the first multi-agent LLM-driven approach for constitutive model generation: a Creator agent proposes a model tailored to the data, while an Inspector agent critically audits each proposal against nine physical constraints and returns it for refinement whenever a violation is detected. We demonstrate this concept with constitutive artificial neural networks (CANNs) and benchmark it on brain tissue and rubber as isotropic materials, and on porcine skin tissue as a transversely isotropic material with a preferred fiber direction, using two different LLM backbones (Claude Opus 4.7 and Kimi K2.5). Whether a generated model satisfies the physical constraints is assessed numerically, by probing each constraint across a broad sample of deformation states, rotations, and perturbation directions. Adding the Inspector raises the share of exported models that pass all these checks from 90% to 95% for Opus and from 47% to 60% for Kimi. In addition, the generated models are on par with or even surpass expert-designed models in accuracy, extrapolate reliably beyond the training data, and generalize remarkably well to unseen loading paths. Separating generation from inspection thus turns LLM-driven constitutive modeling into a substantially more trustworthy process. The paradigm is deliberately technique-agnostic and scales automatically with advances in LLM capability, opening a promising path toward automated, physics-aware model discovery.Publicationtype: Journal Article7 28 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Scalable fabrication and mechanical behaviour of hierarchical porous nickel networksAs the demand for light-weight structural and functional materials grows, the fabrication of hierarchical, high-performance micro- and nano-architectures becomes increasingly important. Here, we present a scalable alloying–dealloying strategy to fabricate porous metal with two- and three-level hierarchical networks (2 L-/3L-HN). By exploiting the vapour pressure difference between Ni and Zn, vapour phase alloying of Ni foam with Zn, followed by vapour phase dealloying of the resulting γ-Zn84Ni16 foam, generates a second hierarchical level, producing 2L-HN Ni or 2L-HN β-Zn50Ni50. Re-alloying 2L-HN β-Zn50Ni50 to 2L-HN γ-Zn84Ni16 via vapour phase alloying while preserving its hierarchical architecture enables chemical dealloying to create a third level of hierarchy at the nanoscale, producing 3L-HN Ni with significantly increased specific surface area. A novel scaling law is proposed to predict the mechanical properties of these hierarchical porous metallic networks as a function of solid fraction, and its validity is supported by compression tests on 2L-HN Ni with varying densities. This work establishes a scalable and versatile route for fabricating multiscale porous metallic networks with light-weight, tunable mechanical performance and high surface area.Publicationtype: Journal Article24 11 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Beyond the size: Assessing the influence of synthesis parameters on ZIF-8 monolith degradation in aqueous environments(Elsevier, 2026-08-28); ; ; 15 13 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Micromechanical insights into tensile deformation of epoxy-infiltrated hierarchical nanoporous copperHierarchical nanoporous metals infiltrated with polymers offer enhanced tensile stability while retaining functional porosity, yet their micromechanical deformation mechanisms remain insufficiently understood. Here, a micromechanics-based finite element framework is developed for epoxy-filled hierarchical nanoporous copper (HNPCu) based on experimentally derived structural parameters. The hierarchical ligament architecture across two structural levels as well as selective epoxy infiltration are explicitly resolved, enabling phase-specific analysis of local stress and strain evolution. The predicted tensile response is validated against experiments for different Cu solid fractions (0.1≤φ≤0.2), and the experimentally observed trends are well reproduced using idealized microstructures. Epoxy infiltration markedly reduces plastic strain localization within the Cu network, leading to a more homogeneous deformation state compared to epoxy-free HNPCu. At the macroscopic level, the tensile response remains largely unaffected by epoxy infiltration at small strains, with differences emerging only at larger deformation. Strain localization is predicted both within Cu ligaments and near Cu–epoxy interfaces, consistent with experimentally observed microcrack formation along phase boundaries and inside the Cu network. These findings provide micromechanical insight into hierarchy-assisted deformation in polymer-infiltrated nanoporous metals and establish a basis for microstructure-guided design of mechanically robust hierarchical materials.Publicationtype: Journal Article28 20 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Dirichlet-type absorbing boundary conditions for ordinary state-based peridynamicsWe present time-domain Dirichlet-type absorbing boundary conditions (ABCs) for 2D ordinary state-based peridynamics using the Linear Peridynamic Solid (LPS) model, aimed at efficiently truncating unbounded elastodynamic domains while retaining the flexibility of arbitrary Poisson ratios. The proposed ABCs are built from a semi-analytical far-field representation expressed as a finite superposition of plane-wave modes satisfying the discrete LPS dispersion relation, so that outgoing waves are absorbed consistently with the numerical P- and S-wave branches and their Poisson-ratio-dependent polarizations. A cloud-based collocation and least-squares procedure eliminates the unknown modal amplitudes locally and yields precomputable updating operators that prescribe boundary displacement and velocity directly within explicit time stepping, avoiding spatial derivatives, transform techniques, auxiliary evolution equations, and surface-correction procedures at truncated horizons. Unlike our earlier bond-based ABC formulations, the present work requires a new state based far-field theory, a new discrete dispersion operator with coupled P- and S-wave branches for general Poisson ratios, and an additional treatment of the nonlocal dilatation field. Numerical benchmarks show that the resulting ABCs strongly suppress nonphysical reflections over a broad range of material parameters, providing a simple and robust alternative to absorbing layers.Publicationtype: Journal Article20 17 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Direct numerical simulation study of the effect of horizontal flow on mixed convection in porous mediaA direct numerical simulation (DNS) study is performed on mixed convection in a chamber filled with a porous medium composed of staggered circular elements. Natural convection is driven by a temperature difference between the two walls, while forced convection is caused by a prescribed horizontal force. The Rayleigh number in the range 1000 ≤ 𝑅𝑎 ≤ 20000, pore-scale Rayleigh number in the range 1.2 ≤ 𝑅𝑎𝐾 ≤ 39.2, Peclet–Rayleigh number ratio in the range 0 ≤ 𝑃 𝑒𝐾∕𝑅𝑎𝐾 ≤ 1, Prandtl number 𝑃 𝑟 = 250, and porosity 𝜙 = 0.46 and 0.56 are considered in the DNS study. The DNS results reveal that pore-scale dispersion caused by natural convection is significant due to the large 𝑅𝑎𝐾. It enhances the merging of small plumes in the boundary layer and reduces the mega-plume number. The horizontal flow has two competing effects on heat transfer. It weakens vertical macroscopic advection and pore-scale dispersion, and thus reduces the heat transfer. However, it also weakens small-scale horizontal motions in the boundary layer, which prevents the mega-plumes from merging and enhances the heat transfer. Consequently, the mega-plume number increases at 𝑅𝑎 = 1000 as 𝑃 𝑒𝐾∕𝑅𝑎𝐾 rises from 0 to 1. At 𝑅𝑎 = 20000, the mega-plume number increases as 𝑃 𝑒𝐾∕𝑅𝑎𝐾 increases from 0 to 0.1; however, it decreases as 𝑃 𝑒𝐾∕𝑅𝑎𝐾 increases to 1, due to strong dispersion caused by the horizontal flow. The overall effect of the horizontal flow is mainly to reduce the Nusselt number. The Nusselt number follows the scaling law 𝑁𝑢 ∼ 𝑅𝑎𝑎, where 𝑎 can be approximated as 𝑎 = 0.5 − 2.5 × 10−6𝑃 𝑒 for the present DNS cases.Publicationtype: Journal Article36 27 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Experimental verification of soft X-ray imaging and RIXS mapping with a reflection zone plate(Optica Publishing Group, 2026-08-05); ; ; We demonstrate two-dimensional (2-D) imaging and resonant inelastic X-ray scattering (RIXS) spectroscopy in the hν2 “mapping” scheme using a reflection zone plate (RZP) at soft X-rays. Experiments at the PETRA III storage ring (DESY) around the N Kα line (392.4 eV) verify that an RZP can be used in the paraxial regime combined with the 1-D line scanning mode for time-efficient full-field imaging of an extended object with an angular size of 2.5 mrad at low aberrations, even for off-design energies, at a spatial resolution of (14–24) μm. A similar setup collects the RIXS spectra of acetonitrile within (388.6–401.8) eV for a variable incident photon energy between 399 eV and 400 eV, at a potential resolution of (0.3 ± 0.1) eV. RZPs with their precise manufacturability, efficiency, and strong dispersion can serve as advantageous diffractive optical elements in soft X-ray microscopy or “photon-in vs. photon-out” spectroscopy.Publicationtype: Journal Article31 23 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Distinct electrification regimes at solid–liquid interfaces revealed by water isotope substitution(American Chemical Society (ACS), 2026-07-28); ; ; ; Solid–liquid contact electrification is widely studied using diverse experimental geometries that are often implicitly assumed to probe equivalent interfacial processes. Here, we directly test this assumption by comparing immersion–emersion, droplet-based contact, and pressure-driven intrusion–extrusion electrification using the same hydrophobic nanoporous silicon monolith and isotopically substituted liquids (H2O and D2O). Despite identical surface chemistry, isotopic substitution produces qualitatively different electrical responses depending on the wetting regime. Immersion–emersion experiments show polarity inversion between H2O and D2O, while droplet measurements reveal distinct charge evolution and periodic opposite-polarity events. In contrast, forced nanopore intrusion preserves polarity but strongly enhances electrical output for D2O. These results demonstrate that wetting of surface nanoroughness during droplet, vs immersion–emersion, vs complete nanopores wetting upon intrusion–extrusion correspond to fundamentally different electrification states. By using isotope substitution as a controlled probe, this work establishes a general framework for disentangling protocol-dependent effects in solid–liquid contact electrification and triboelectric energy conversion.Publicationtype: Journal Article5 10 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , The Cahn–Hilliard residuum and its implications for critical-point wetting at solid solution surfacesAs part of their seminal 1958 analysis of nonuniform solutions, Cahn and Hilliard [J. Chem. Phys. 28, 258–267 (1958)] identified the Laplacian of the composition field as the key contribution to the excess free energy in solids with a conserved network of discrete atomic sites. Integration by parts converted to the now familiar gradient-square form underlying phase-field simulations and studies of critical-point wetting. The residuum from the integration by parts has since been ignored. Here, we examine its implications using critical-point wetting at the surface of an Ising-type solid solution for a representative case. As a benchmark, atomistic Monte Carlo simulation shows a continuous increase in wetting-layer thickness up to the bulk critical temperature. In contrast, the classical gradient-square continuum model predicts a first-order wetting transition. A more realistic Laplacian-based continuum formulation does not readily admit physically meaningful minimization by standard variational methods. As a discrete approach, a plane-by-plane model with an excess energy based on a second-difference (curvature) operator yields solutions consistent with the benchmark. Summation by parts transforms this operator into a first-difference- (gradient-) square form, and neglect of the residual term again leads to an incorrect first-order transition. Thus, the choice between curvature and gradient-square formulations alters the predicted character—first-order transition or continuous evolution in layer thickness—of the wetting, underscoring the fundamental importance of this choice.Publicationtype: Journal Article23 28 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Surface and boundary corrections in peridynamics using optimized nodal influence weights(Wiley, 2026-07-14); ; ; ; Peridynamics (PD), similarly to some other nonlocal continuum theories, exhibits truncated interaction horizons near free surfaces, cracks, and voids in bounded domains. This loss of neighbors causes artificial surface effects and inconsistencies in the derivative and energy operators that persist under discretization refinement, limiting PD accuracy and robustness. First, the analysis and numerical isolation of the effects of horizon truncation on these operators are carried out, showing how it induces surface softening in bond‐based and stiffening/softening in state‐based PD formulations. Then, a purely PD‐based surface correction is proposed to restore full‐horizon behavior while preserving the original horizon radius and bond topology. Each node is assigned a scalar influence weight, and every bond is scaled by the average of the endpoint weights to maintain symmetry. The nodal influence weights are computed in a preprocessing optimization step enforcing agreement between truncated‐ and full‐horizon derivative and energy operators. Unlike existing approaches, the proposed method does not rely on ghost particles, variable horizons, or reference solutions from classical continuum mechanics (CCM). Benchmarks in one, two, and three dimensions, including a dynamic brittle fracture test, show that the optimized nodal influence weights reduce boundary‐induced surface effects, improve energy consistency, and accelerate convergence of PD solutions. Analytical evaluation of the calibration targets over full‐horizons also improves interior volume integration accuracy. The proposed scheme is simple to implement in existing PD codes, incurs only a modest preprocessing cost, performs robustly for flat and curved boundaries on both regular and irregular point sets, produces reliable crack paths, and applies to both bond‐based and ordinary state‐based PD formulations. An open‐source Python implementation, perifit, is provided.Publicationtype: Journal Article41 62