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Strain–Stress Estimation of Vibrational Beam and Plate Using Radiative Energy Transfer Method

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Journal of applied Mechanics 2025年第6期92卷 061004页

作者： Zhong, Qiang Cui, Ding Xian, Yuqiang Dai, Chenghao Chen, Haibo National Key Laboratory of Science and Technology on Advanced Laser and High Power Microwave Institute of Applied Electronics Chinese Academy of Engineering Physics Mianyang Sichuan 621025 China CAS Key Laboratory of Mechanical Behavior and Design of Materials Department of Modern Mechanics University of Science and Technology of China Hefei Anhui 230027 China

This study aims to present simple conversion expressions of strains–stresses and the energy density for beams and plates subjected to high-frequency random forces using the radiative energy transfer method (RETM). Euler–Bernoulli beam theory and Kirchhoff plate theory are introduced to describe the deflections of beam and plate. The conversion expressions of strains–stresses and energy density for a single propagation wave are quickly established by dispersion relations. For multi-cylindrical wave fields, the strains–stresses are superimposed by the wave fields generated by the actual source in the domain and the wave fields reflected by the fictitious sources at boundaries according to Huygens’ superposition principle. The conversion expressions of strains–stresses and energy density in the energy finite element method (EFEM), which supposes that the superposition of plane waves forms the wave field, are also derived. Numerical examples indicate that in damping-frequency space, the conversion expressions obtained by RETM have a wider application region than those obtained by EFEM and can be applied to a low-frequency band than the corresponding energy algorithm itself.

关键词： vibration Density structures Waves stress analysis Stress wave propagation

A simultaneous explanation of XTE J1814-338 and HESS J1731-347 objects using K− and K¯0 condensates

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arXiv 2024年

作者： Veselský, M. Petousis, V. Koliogiannis, P.S. Moustakidis, Ch.C. Leja, J. Institute of Experimental and Applied Physics Czech Technical University Prague110 00 Czech Republic Department of Physics Faculty of Science University of Zagreb Bijenička cesta 32 Zagreb10000 Croatia Department of Theoretical Physics Aristotle University of Thessaloniki Thessaloniki54124 Greece Faculty of Mechanical Engineering Slovak University of Technology in Bratislava Bratislava81231 Slovakia

The recent observation of the compact star XTE J1814-338 with a mass of (Equation presented) and a radius of (Equation presented), together with the HESS J1731-347, which has a mass of (Equation presented) and a radius of (Equation presented), they provide evidence for the possible presence of exotic matter in the core of neutron stars and significantly enhance our understanding of the equation of state for the dense nuclear matter. In the present srtudy, we investigate the possible existence of neutral anti-kaons and negative charged kaons in neutron stars by employing the Relativistic Mean Field model with first order kaonic (K− and K¯0) condensates. To the best of our knowledge, this represents a first alternative attempt aimed to explain the bulk properties of the XTE J1814-338 object and at the same time the HESS J1731-347 object, using a mixture of kaons condensation in dense nuclear matter. In addition, we compare our analysis approach with the recent observation of PSR J0437-4715 and PSR J1231-1411 pulsars, proposing that to explain all objects simultaneously, it is essential to consider two distinct branches, each corresponding to a different composition of nuclear matter. Copyright © 2024, The Authors. All rights reserved.

关键词： Neutrons

Inferring Ventilation Rates with Quantified Uncertainty in Operational Rooms Using Point Measurements of Carbon Dioxide: Classrooms as a Case Study

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SSRN

SSRN 2023年

作者： Finneran, Joshua Burridge, Henry Wolfson School of Mechanical Electrical and Manufacturing Engineering Loughborough University Loughborough United Kingdom Department of Applied Mathematics and Theoretical Physics University of Cambridge Cambridge United Kingdom Department of Civil and Environmental Engineering Imperial College London London United Kingdom

We present a robust integral method to estimate the daily mean per-person ventilation rate Qpp based on carbon dioxide (CO2) concentration measurements in operational spaces, and limited other data. The method makes no assumptions regarding the ventilation provision throughout the day, nor requires the room to be in a steady state, nor the air within to be well-mixed. We demonstrate that several integral parameters remain reliably close to a value of unity, despite large variations in room conditions. Evaluating the likely distributions of integral parameters provides a method to quantify the uncertainty bounds and therefore assess the reliability of these ventilation estimates. Taking school classrooms as a case study, estimates of Qpp based on measured CO2 are shown to exhibit uncertainty bounds (confidence intervals of 95%) of around ±24% if no other data than the classroom timetable, is available. Deploying four sensors within a classroom is expected to halve the uncertainty bounds to around ±12%. Moreover, when the same classroom is occupied similarly on different days then the framework evidences that simply taking the ratio of the integral of excess CO2 for the two days is a direct measure of the relative inter-day per-person ventilation rates for the two days. These significant findings offer great scope to facilitate more reliable ventilation estimates, particularly from large-scale data sets of CO2 measured in operational spaces, to better inform assessments of indoor air quality. © 2023, The Authors. All rights reserved.

关键词： Carbon dioxide

Experimental identification of blade-level forces, torque, and pitching moment for cross-flow turbines

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arXiv 2025年

作者： Snortland, Abigale Van Ness, Katherine Franck, Jennifer A. Athair, Ari Williams, Owen Polagye, Brian University of Washington Department of Mechanical Engineering 3900 E Stevens Way NE SeattleWA98195 United States University of Washington Applied Physics Lab 1013 NE 40th St SeattleWA98105 United States University of Wisconsin-Madison Department of Mechanical Engineering 1500 Engineering Dr MadisonWI53706 United States University of Washington Department of Aeronautics and Astronautics 3940 Benton Lane NE SeattleWA98105 United States

Cross-flow turbine power is a net sum of power generation from rotating blades and power loss from rotating support structures. While the aggregate forces and torques at the turbine level are important for end use, these can inhibit a deeper understanding of fluid-structure interactions. Identification of blade-level forces and torques allows for specific investigations into how the fluid forcing on the blade drives rotation and can aid blade structural design. Here, we present a physics-based methodology for extracting blade-level forces and torques from experimental measurements at the axis of rotation of a cross-flow turbine, and demonstrate strong agreement with equivalent blade-only simulations. In doing so, we highlight the significance of the commonly ignored pitching moment term which is found to oppose power generation and drive performance degradation in the downstream portion of the rotation. © 2025, CC BY-SA.

关键词： Turbine components

Exploring the Relationship Between Softness and Excess Entropy in Glass-forming Systems

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arXiv 2023年

作者： Graham, Ian R. Arratia, Paulo E. Riggleman, Robert A. Department of Physics and Astronomy University of Pennsylvania PhiladelphiaPA19104 United States Department of Mechanical Engineering and Applied Mechanics University of Pennsylvania PhiladelphiaPA19104 United States Department of Chemical and Biological Engineering University of Pennsylvania PhiladelphiaPA19104 United States

We explore the relationship between a machine-learned structural quantity (softness) and excess entropy in simulations of supercooled liquids. Excess entropy is known to scale well the dynamical properties of liquids, but this quasi-universal scaling is known to breakdown in the supercooled and glassy regimes. Using numerical simulations, we test whether a local form of the excess entropy can lead to predictions that derive from softness, which has been shown to correlate well with the tendency for individual particles to rearrange. To that end, we explore leveraging softness to compute excess entropy in the traditional fashion over softness groupings. Our results show that by computing the excess entropy over softness-binned groupings, we can build a strong quantitative relationship between the rearrangement barriers across the explored systems. © 2023, CC BY.

关键词： Entropy

Recent Advances and Applications of Machine Learning in Experimental Solid Mechanics: A Review

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arXiv 2023年

作者： Jin, Hanxun Zhang, Enrui Espinosa, Horacio D. Department of Mechanical Engineering Northwestern University EvanstonIL60208 United States Theoretical and Applied Mechanics Program Northwestern University EvanstonIL60208 United States Division of Applied Mathematics Brown University ProvidenceRI02912 United States

For many decades, experimental solid mechanics has played a crucial role in characterizing and understanding the mechanical properties of natural and novel materials. Recent advances in machine learning (ML) provide new opportunities for the field, including experimental design, data analysis, uncertainty quantification, and inverse problems. As the number of papers published in recent years in this emerging field is exploding, it is timely to conduct a comprehensive and up-to-date review of recent ML applications in experimental solid mechanics. Here, we first provide an overview of common ML algorithms and terminologies that are pertinent to this review, with emphasis placed on physics-informed and physics-based ML methods. Then, we provide thorough coverage of recent ML applications in traditional and emerging areas of experimental mechanics, including fracture mechanics, biomechanics, nano- and micro-mechanics, architected materials, and 2D material. Finally, we highlight some current challenges of applying ML to multi-modality and multi-fidelity experimental datasets and propose several future research directions. This review aims to provide valuable insights into the use of ML methods as well as a variety of examples for researchers in solid mechanics to integrate into their experiments. © 2023, CC BY.

关键词： Machine learning

Electron Ptychography for Investigating Magnetic Textures in Micro- and Nano- Scale Magnets via Lorentz Transmission Electron Microscopy

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Microscopy and microanalysis : the official journal of Microscopy Society of America, Microbeam Analysis Society, Microscopical Society of Canada 2023年第1期29卷 1847-1848页

作者： Trujillo, Kayna L Mendoza Divan, Ralu N S Li, Yue Jiang, Yi McCray, Arthur R C Petford-Long, Amanda K. Phatak, Charudatta Department of Materials Science and Engineering Northwestern University Evanston IL United States Materials Science Division Argonne National Laboratory Lemont IL United States Center for Nanoscale Materials Argonne National Laboratory Lemont IL United States Advanced Photon Source Argonne National Laboratory Lemont IL United States Applied Physics Program Northwestern University Evanston IL United States

Complete Solution of Large Plastic Deformation of Square Plates Under Exponentially Decaying Pulse Loading

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Acta Mechanica Solida Sinica 2021年第6期34卷 922-936页

作者： Faliang Chen Lanren Tian T.X.Yu Ling Zhu Institute of Applied Physics and Computational Mathematics BeijingChina Key Laboratory of High Performance Ship Technology(Wuhan University of Technology) Ministry of EducationWuhanChina Departments of Naval Architecture Ocean and Structural Engineering School of TransportationWuhan University of TechnologyWuhanChina Department of Mechanical and Aerospace Engineering The Hong Kong University of Science and TechnologyClear Water BayKowloonHong KongChina

The rigid-plastic assumption has greatly simplified the theoretical analysis of dynamic plastic response of *** this framework,a common tool is the modal technique using approximate independent yield criteria,which leads to upper-and lower-bound solutions,but usually with poor *** this paper,by utilizing the membrane factor method(MFM),the large-deflection dynamic plastic response of square plates subjected to exponentially decaying pulse loading is analyzed by taking both the transient response phase and the exact yield criterion into *** on the combination of saturation analysis(SA)and MFM,the complete solutions and regressive formulae of saturated deflection and saturated impulse are *** the dynamic behavior of plates under rectangular pulse loading serves as a benchmark of pulse-equivalent techniques,the large plastic deformation of square plates under short-duration rectangular pulse is also analyzed in ***,by comparing the SA results of pulse-loaded square plates with different boundary conditions,it is found that the saturated deflection and saturated impulse of the fully clamped and simply supported square plates both increase linearly with the pulse amplitude,and the slopes are approximately the same,so the conversion between the SA quantities of plates with different boundary conditions can be easily achieved.

关键词： Exponentially decaying(ED)pulse loading Rectangular pulse loading Membrane factor method(MFM) Saturation analysis(SA) Complete solution

Controlling Pore Position during Transient Liquid Phase Bonding for High-temperature Soldering Processes

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Journal of Japan Institute of Electronics Packaging 2024年 17卷 E23-009-1-E23-009-9页

作者： Razak, N.R. Abdul Tan, Xin F. McDonald, Stuart D. Bermingham, Michael J. Venezuela, Jeffrey Nishimura, Tetsuro Nogita, Kazuhiro School of Mechanical and Mining Engineering The University of Queensland BrisbaneQLD4072 Australia Perlis02600 Malaysia Perlis02600 Malaysia Department of Applied Quantum Physics and Nuclear Engineering Kyushu University Fukuoka819-0395 Japan Nihon Superior Co. Ltd. Osaka Suita City564-0063 Japan

Exploiting the growth rate dependency of intermetallic compounds (IMCs) on the substrate composition, the possibility of controlling porosity during transient liquid phase (TLP) bonding via a composition gradient is investigated. A Cu substrate with a variable Ni concentration was prepared through selective electroplating and subsequent heat treatment. When this substrate reacted with a molten Sn-rich alloy, there was a non-uniform growth of the Cu6Sn5 IMC. It is proposed that by tailoring the direction of the composition gradient in the substrate, the IMC growth rate can be controlled in such a way as to progressively move the solid-liquid front to redistribute any porosity away from the central region of the joint and thereby improve reliability. Copyright © The Japan Institute of Electronics Packaging.

关键词： Soldering