Seismic capacity of purely compressed shells based on Airy stress function

Continuum Mechanics and Thermodynamics, Journal Year: 2025, Volume and Issue: 37(2)

Published: Jan. 9, 2025

Purely compressed shells are often elegant and highly efficient structural forms, but this leanness may create risk if they subjected to unexpected patterns magnitudes of loading, such as arise due seismic events. In the same way that historic masonry structures were designed sustain loads by activating purely compressive force paths, a modern metamaterial can be for specific purposes following logic. Conventional analysis methods compression-only vaults, developed structures, have tended not model combined vertical horizontal directly. This has created significant challenge engineers assessing vaults or designing new shells. To address gap, paper presents an enhanced method based on membrane equilibrium (MEA) static theorem limit analysis. approach is first application MEA directly consider body forces acting shell through parametric formulation Airy stress function. The applied case study sail vault loads. Moreover, it demonstrated how used define iso-resistant shapes offer more sustainable design options while preserving capacity.

Language: Английский

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A review of inverse problems for generalized elastic media: formulations, experiments, synthesis

Continuum Mechanics and Thermodynamics, Journal Year: 2024, Volume and Issue: 36(6), P. 1413 - 1453

Published: Aug. 5, 2024

Abstract Starting from the seminal works of Toupin, Mindlin and Germain, a wide class generalized elastic models have been proposed via principle virtual work, by postulating expressions energy enriched additional kinematic descriptors or higher gradients placement. More recently, such adopted to describe phenomena which are not consistent with Cauchy-Born continuum, namely size dependence apparent moduli observed for micro nano-objects, wave dispersion, optical modes band gaps in dynamics heterogeneous media. For those structures mechanical response is affected surface effects predominant respect bulk, scale external actions interferes characteristic heterogeneities. Generalized continua very often referred as media microstructure although rigorous deduction lacking between specific microstructural features constitutive equations. While forward modelling predictions observations provided, actual at multiple scales can be used inversely integrate some lack information about model. In this review paper, investigated standpoint inverse problems, focusing onto three topics, tightly connected located border multiscale experimental assessment, namely: (i) parameter identification models, including asymptotic methods homogenization strategies; (ii) design non-conventional tests, possibly integrated full field measurements advanced modelling; (iii) synthesis meta-materials, microstructures fit target behaviour macroscale. The scientific literature on media, focus gradient fathomed search questions typical problems theory issues related estimation, providing hints perspectives future research.

Language: Английский

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Emergence of bimodulus (tension–compression asymmetric) behavior modeled in granular micromechanics framework

Mathematics and Mechanics of Solids, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 10, 2025

Many materials exhibit a bimodulus behavior which manifests as tension–compression asymmetry under uniaxial loading conditions. From the viewpoint of engineering analyses and design, attempts have been made to properly account for this by defining models various multiaxial The available in literature propose complex set cases valid different combination tensile/compressive characterized either strain or stress space based on classical continuum mechanics. key drawback these propositions is attempt reduce an inherently nonlinear problem simpler linear one opposition clear evidence dependency. Moreover, proposed approaches are generally conceived orthotropic framework even though material initially isotropic. It only upon deformation that apparent anisotropy induced due asymmetry, cannot be considered initial, reference, configuration. Indeed, from fundamental viewpoint, emergence macroscale has its roots microscale mechanics otherwise isotropic (or other) microstructure. To further expatiate view, we exploit granular micromechanics paradigm present simple model within reference Using approach, shown emerge naturally without inconsistencies observed methods literature.

Language: Английский

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Hybrid mechanical metamaterials: advances of multi-functional mechanical metamaterials with simultaneous static and dynamic properties

Heliyon, Journal Year: 2025, Volume and Issue: 11(3), P. e41985 - e41985

Published: Jan. 18, 2025

Mechanical metamaterials are architected structures with unique functionalities, such as negative Poisson's ratio and stiffness, which widely employed for absorbing energy of quasi-static impact loads, giving improved mechanical response. Acoustic/elastic metamaterials, their dynamic counterparts, rely on frequency-dependent properties microstructure elements, including mass density bulk modulus, to control the propagation waves. Although introduced significant contribution solving independently static problems, they were facing certain resistance use in real-world engineering mainly because a lack integrated systems possessing both vibration attenuation performance. Advances manufacturing processes material computational science now enable creation hybrid offering multifunctionality terms simultaneous properties, them ability controlling waves while withstanding applied loading conditions. Exploring towards this direction, review paper introduces design process multifunctional properties. We emphasize still remaining challenges how can be potentially implemented solutions.

Language: Английский

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A granular micromechanic-based model for Ultra High Performance Fiber-Reinforced Concrete (UHP FRC)

International Journal of Solids and Structures, Journal Year: 2024, Volume and Issue: 297, P. 112844 - 112844

Published: April 30, 2024

Language: Английский

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Optimization of an architected composite with tailored graded properties

Zeitschrift für angewandte Mathematik und Physik, Journal Year: 2024, Volume and Issue: 75(4)

Published: June 15, 2024

Abstract The aim of the present study is to design a solid material with specific and tailored mechanical properties through suitably defined framework evaluate effectiveness different microstructure geometries in an engineering perspective. To these ends, topology optimization algorithms are applied on 2D homogenized equivalent model periodic structure. framework, developed previous work for lattices made regular hexagons, here expanded validated also cases circular square unit cells. proposed approach involves optimizing porosity distribution solid, obtained Bloch–Floquet-based analysis, within lattice cells forming core element sandwich panel. Finite-element analyses fine structural models carried out order validate procedure, beyond particular choice cell geometry detect its limits.

Language: Английский

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A Pilot Study on the Age-Dependent, Biomechanical Properties of Longitudinal Ligaments in the Human Cervical Spine

Bioengineering, Journal Year: 2025, Volume and Issue: 12(1), P. 61 - 61

Published: Jan. 13, 2025

The cervical spine ligaments, including the anterior longitudinal ligament (ALL) and posterior (PLL), play a key role in maintaining spinal stability by limiting excessive movements. This study investigates how ageing affects mechanical properties of these ligaments. We analysed 33 samples from 12 human spines (15 ALL, 18 PLL), averaging data same donors for independent analysis, resulting final (8 10 PLL). To explore age-related changes, we classified into two groups—below above 50 years old—aligning with peak incidence major musculoskeletal disorders. investigation concentrated on effects age four parameters uniaxial stress–stretch curve: initial tangent stiffness (E0), maximum (Em), ultimate stress (Pu) stretch (λu). When effect is neglected, then behaviours both ALL PLL appeared similar. However, when introducing as variable context PLL, statistically significant differences became evident. findings underscored reduction (p-value = 0.0147), 0.0009), 0.0024) were grouped under consequence ageing.

Language: Английский

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A parametric study on a granular micromechanics continuum-based hemivariational approach: unraveling the emergence of critical states in granular materials

Mathematics and Mechanics of Complex Systems, Journal Year: 2025, Volume and Issue: 13(1), P. 25 - 54

Published: Feb. 10, 2025

Language: Английский

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Topology-optimized reflection-type pentamode metasurfaces for broadband underwater beam regulation

Wave Motion, Journal Year: 2025, Volume and Issue: unknown, P. 103515 - 103515

Published: Feb. 1, 2025

Language: Английский

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Mandibular Implants: A Metamaterial‐Based Approach to Reducing Stress Shielding

Advanced Healthcare Materials, Journal Year: 2025, Volume and Issue: unknown

Published: April 4, 2025

Biomechanical complications, such as stress shielding, bone resorption, and reconstruction failure, are prevalently associated with solid titanium mandible plates. This study evaluates the potential of metamaterial designs porous gyroid microarchitectures, to enhance biomechanical stimulation mitigate these complications. A novel plate is compared plates, both patient-specifically designed fabricated from Ti6Al4 V alloy. Stress shielding assessed through photoelasticity experiments validated finite element analysis (FEA). Transparent models loaded incrementally (0-1000 N) analyze distributions in implants, screws, segments. The reduces concentrations distant mandibular regions defect, while increasing around screws near favoring local mechanical stimulation. FEA confirms improved load distribution (p = 0.003). However, exhibited a lower load-bearing capacity, failing at 775 N, withstood 1800 N without failure. Yet, design effectively reduced thereby enhancing function critical regions. Hence, despite their they can, potentially, preserve integrity prevent implant failure that should be future (pre-)clinical studies.

Language: Английский

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