Nondestructive method for predicting buckling loads of sandwich plates with functionally graded porous layers using particle swarm optimization and bagging technique (machine learning)

Mechanics Based Design of Structures and Machines, Journal Year: 2025, Volume and Issue: unknown, P. 1 - 33

Published: April 16, 2025

Language: Английский

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Biomechanical and histomorphometric characterization of the melatonin treatment effect in the carotid artery subjected to hypobaric hypoxia

Frontiers in Bioengineering and Biotechnology, Journal Year: 2025, Volume and Issue: 13

Published: April 16, 2025

This study aims to assess the efficacy of melatonin in mitigating adverse effects hypobaric hypoxia on cardiovascular system neonatal lambs (30 days old). Two groups were considered for this purpose: (i) Melatonin-treated group (N = 5) and (ii) Control 6) without treatment. All subjects exposed during gestation perinatal periods, with administered after birth. The focused carotid artery, a known predictor risk. Biomechanical tests, morphometric, histological measurements conducted, numerical model was developed based biomechanical data. Key findings showed remodeling effects: Firstly, realignment collagen fibers towards longitudinal direction observed treatment, similar non-hypoxic arteries. Second, changes residual stress ex-vivo luminal radius noted, aiming reduce wall increase vascular resistance. These indicate an antihypertensive response, reducing increased blood pressure flow due hypoxia. demonstrates that histomorphometric methodologies effectively beneficial treatment under exposure.

Language: Английский

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Nonlinear buckling and free vibration analysis of auxetic graphene origami composite beams under nonuniform thermal environment

Mechanics Based Design of Structures and Machines, Journal Year: 2024, Volume and Issue: unknown, P. 1 - 32

Published: Oct. 24, 2024

This study examines the thermo-mechanical behavior of auxetic metamaterial beams enhanced by graphene origami (GOri) under spatially varying nonuniform temperature distributions (SVTD). Utilizing Timoshenko beam theory considering von-Kármánn type nonlinear strain–displacement relationship, GOri are modeled as layered structures. The Ritz method is employed to solve equilibrium equations, analyzing impact distribution patterns, content, and folding degree on post-buckling vibration paths. effects five SVTDs, three end conditions, patterns buckling, behavior, free characteristics explored. Findings reveal that parabolic with peak temperatures at ends (P-MAE) results in higher critical frequencies. research provides crucial insights into design optimization GOri-enabled structures complex thermal environments, highlighting significant influence along beam's length.

Language: Английский

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Vibration response of sandwich plate reinforced by GPLs/GOAM

Mechanics Research Communications, Journal Year: 2024, Volume and Issue: unknown, P. 104334 - 104334

Published: Sept. 1, 2024

Language: Английский

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Performance enhancement energy harvesting from aeroelastic vibrations using a van der Pol circuit

Mechanics Based Design of Structures and Machines, Journal Year: 2024, Volume and Issue: 53(3), P. 2390 - 2402

Published: Oct. 7, 2024

This paper explores galloping vibration-based electromagnetic energy harvesting (EH) in a Duffing-Rayleigh oscillator coupled to storage RLC resonator circuit with van der Pol model. Aeroelastic instability induces the mechanical system's self-induced vibration. The electromechanical coupling mechanism between resonant and structure is obtained by permanent interaction of magnet coil. We examine two cases comparative study. In first case, we use an without second case considers Firstly, modulation equations slow flow vibration output voltage responses are using complexification-averaging (CX-A) method. Furthermore, analytical approximate solutions steady-state derived. results have been confirmed numerical simulations. Results show that can provide higher electrical introducing instead circuit. Moreover, presence model significantly reduce critical wind speed required harvest energy. result may optimization process be used supply some guidelines design vibrations-based harvesters.

Language: Английский

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Active vibration control of metal foam reinforced agglomerated graphene nanoplatelets nanocomposite truncated conical shells with piezoelectric layers

Mechanics Based Design of Structures and Machines, Journal Year: 2024, Volume and Issue: unknown, P. 1 - 26

Published: Oct. 15, 2024

This study examines active vibration control (AVC) in a truncated conical shell composed of metal foam reinforced with agglomerated graphene nanoplatelets and integrated piezoelectric layers functioning as sensors actuators. Both complete partial agglomeration states are considered based on the Eshelby–Mori–Tanaka approach, mechanical properties porous core characterized using closed-cell model. The governing equations motion derived Hamilton's principle, two-dimensional axisymmetric elasticity theory, solved through finite element method coupled Newmark method. Vibration mitigation is achieved fractional-order fuzzy proportional–integral–derivative (PID) controller. A comprehensive parametric conducted, examining effects geometric dimensions, various boundary conditions, reinforcement parameters (including weight fraction, distribution patterns, parameters), porosity pore size, pattern) shell. Numerical simulations performed to assess effectiveness proposed AVC system reducing structural vibrations compared constant velocity feedback approach. controller reduced central deflection from 12.65 5.089 μm, while PID further improved it 2.348 representing 53.86% enhancement over

Language: Английский

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Hemodynamics of Asymmetrically Stenotic Vertebral Arteries Based on Fluid-solid Coupling

Published: Oct. 21, 2024

Stenosis in the vertebral artery, often associated with atherosclerosis, presents complexities regarding relationship between internal resistance, shear stress and geometric characteristics of stenosis lesions. This study aims to elucidate these relationships through computational simulations utilizing medical imaging data human arteries. Various models representing different stenotic configurations were constructed, allowing for comprehensive analysis via Computational Fluid Dynamics (CFD) Fluid-Structure Interaction (FSI) methods. Hemodynamic parameters such as blood flow velocity, time-averaged wall (TWASS), oscillation index (OSI), relative retention time (RRT), solid mechanics indicators including total deformation vascular Von-Mises evaluated. Our findings revealed that lesion modes had impacts on field artery. Upon comparing mathematical model CFD FSI results, it was found an augmented rate led creation a watershed environment within vessel, thereby expediting onset atherosclerosis. In cases where artery experienced complete narrowing due consistent rate, there substantial rise velocity. Neglecting timely intervention alter heightened peril triggering dissection or even puncturing vessel directly.

Language: Английский

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