• Title/Summary/Keyword: nonlocality

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Plasticity Model for Directional Nonlocal Crack Damage of Concrete (콘크리트의 방향적 비국소 균열 손상을 위한 소성모델)

  • Kim Jae-Yo;Park Hong-Gun
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2006.04a
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    • pp.914-921
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    • 2006
  • To describe the effect of the numerous and various oriented microcracks on the compressive and tensile concrete behaviors, the directional nonlocality is defined. The plasticity model using multiple failure criteria is developed for RC planar members in tension-compression. The crack damages are defined in the pre-determined reference orientations, and then the total crack damage is calculated by integrating multi-oriented crack damages. To describe the effect of directional nonlocality on the anisotropic tensile damage, based on the existing test results, the nonlocal damage factor is defined in each reference orientation. The reduced compressive strength in the cracked concrete is defined by the multi-oriented crack damages defined as excluding the tensile normal plastic strain from the compressive equivalent plastic strain. The proposed model is implemented to finite element analysis, and it is verified by comparisons with various existing panel test results.

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A GN-based modified model for size-dependent coupled thermoelasticity analysis in nano scale, considering nonlocality in heat conduction and elasticity: An analytical solution for a nano beam with energy dissipation

  • Hosseini, Seyed Mahmoud
    • Structural Engineering and Mechanics
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    • v.73 no.3
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    • pp.287-302
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    • 2020
  • This investigation deals with a size-dependent coupled thermoelasticity analysis based on Green-Naghdi (GN) theory in nano scale using a new modified nonlocal model of heat conduction, which is based on the GN theory and nonlocal Eringen theory of elasticity. In the analysis based on the proposed model, the nonlocality is taken into account in both heat conduction and elasticity. The governing equations including the equations of motion and the energy balance equation are derived using the proposed model in a nano beam resonator. An analytical solution is proposed for the problem using the Laplace transform technique and Talbot technique for inversion to time domain. It is assumed that the nano beam is subjected to sinusoidal thermal shock loading, which is applied on the one of beam ends. The transient behaviors of fields' quantities such as lateral deflection and temperature are studied in detail. Also, the effects of small scale parameter on the dynamic behaviors of lateral deflection and temperature are obtained and assessed for the problem. The proposed GN-based model, analytical solution and data are verified and also compared with reported data obtained from GN coupled thermoelasticity analysis without considering the nonlocality in heat conduction in a nano beam.

Effect of the laser pulse on transient waves in a non-local thermoelastic medium under Green-Naghdi theory

  • Sarkar, Nantu;Mondal, Sudip;Othman, Mohamed I.A.
    • Structural Engineering and Mechanics
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    • v.74 no.4
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    • pp.471-479
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    • 2020
  • This paper aims to study the effect of the elastic nonlocality on the transient waves in a two-dimensional thermoelastic medium influenced by thermal loading due to the laser pulse. The bounding plane surface is heated by a non-Gaussian laser beam. The problem is discussed under the Eringen's nonlocal elasticity model and the Green-Naghdi (G-N) theory with and without energy dissipation. The normal mode analysis method is used to get the exact expressions for the physical quantities which illustrated graphically by comparison and discussion. The effects of nonlocality and different values of time on the displacement, the stresses, and the temperature were made numerically. All the computed results obtained have been depicted graphically and explained.

Photon wavefunction 과 two-photon 위그너 함수

  • Jo, Gi-Yeong;No, Jae-U
    • Proceedings of the Optical Society of Korea Conference
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    • 2009.02a
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    • pp.195-196
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    • 2009
  • 최근 Two-particle 위그너 함수 를 이용한 quantum nonlocality의 검증이 시도되고 있다. 우리는 Coherence function에 대한 two-photon위그너 함수를 측정하는 법을 개발했으나, 이를 일반적인 two-particle 위그너 함수로 해석하기 위해서는 photon wavefunction 개념이 필요하다. Two-photon 위그너 함수와 photon wavefunction 에 대한 논의들을 소개한다.

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Elastic wave phenomenon of nanobeams including thickness stretching effect

  • Eyvazian, Arameh;Zhang, Chunwei;Musharavati, Farayi;Khan, Afrasyab;Mohamed, Abdeliazim Mustafa
    • Advances in nano research
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    • v.10 no.3
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    • pp.271-280
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    • 2021
  • The present work deals with an investigation on longitudinal wave propagation in nanobeams made of graphene sheets, for the first time. The nanobeam is modelled via a higher-order shear deformation theory accounts for both higher-order and thickness stretching terms. The general nonlocal strain gradient theory including nonlocality and strain gradient characteristics of size-dependency in order is used to examine the small-scale effects. This model has three-small scale coefficients in which two of them are for nonlocality and one of them applied for gradient effects. Hamilton supposition is applied to obtain the governing motion equation which is solved using a harmonic solution procedure. It is indicated that the longitudinal wave characteristics of the nanobeams are significantly influenced by the nonlocal parameters and strain gradient parameter. It is shown that higher nonlocal parameter is more efficient than lower nonlocal parameter to change longitudinal phase velocities, while the strain gradient parameter is the determining factor for their efficiency on the results.

Rayleigh waves in nonlocal porous thermoelastic layer with Green-Lindsay model

  • Ismail Haque;Siddhartha Biswas
    • Steel and Composite Structures
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    • v.50 no.2
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    • pp.123-133
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    • 2024
  • The paper deals with the propagation of Rayleigh waves in a nonlocal thermoelastic isotropic layer which is lying over a nonlocal thermoelastic isotropic half-space under the purview of Green-Lindsay model and Eringen's nonlocal elasticity in the presence of voids. The normal mode analysis is employed to the considered equations to obtain vector matrix differential equation which is then solved by eigenvalue approach. The frequency equation of Rayleigh waves is derived and different particular cases are also deduced. The effects of voids and nonlocality on different characteristics of Rayleigh waves are presented graphically.

An exploratory study for an evidence of electroencephalographic changes in isolated subjects for distant mental intention

  • Kim, Dae-Keun
    • Science of Emotion and Sensibility
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    • v.17 no.4
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    • pp.51-60
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    • 2014
  • This double-blind study, as a human experiment of nonlocality, investigated the effects of senders' intention on the central nervous system of a distant human receiver and it explored the roles that motivation might have in modulating these effects. Whole brain activity was measured in the receiver whom was asked to relax in a distant room for 16 minutes; the sending person directed intention of oneness toward the receiver during repeated variable-second epochs separated by variable-second non-intention epochs. The total length of intention epochs and that of nonintention epochs were balanced. Eighteen sessions were conducted. In 9 of those sessions, the sender was the receiver's lover. In another 9 of those sessions, the sender was just acquainted with the receiver before the session. The receiver's whole brain activity recorded during the intention epochs were compared with the same measures recorded during the nonintention epochs used as controls. The statistical difference between the intentions versus controls across 18 sessions was examined by paired-t test. In addition, subgroup analysis for the 9 couple sessions and 9 non-couple sessions were additionally examined by the same test. The effect of distant intentionality decreased slow waves or increased EEG fast waves mainly in frontal regions, and increased EEG coherence during the intention epochs. The effects was not statistically significant after Bonferroni correction, but the couple sessions combined showed the largest effect followed by all sessions combined. Non-couple sessions combined showed the smallest effect. The changes in EEG power mean that receiver participants became more alert during the intention epochs and the change in EEG coherence might be evidence of coherent heart influence on EEG activity. Planned comparison with specific hypothesis testing for the suggested changes in this study have to be followed for an evidence of electroencephalographic changes in isolated subjects for the distant mental intention.

Deformation in a nonlocal magneto-thermoelastic solid with hall current due to normal force

  • Lata, Parveen;Singh, Sukhveer
    • Geomechanics and Engineering
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    • v.22 no.2
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    • pp.109-117
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    • 2020
  • The present article is concerned about the study of disturbances in a homogeneous nonlocal magneto-thermoelastic medium under the combined effects of hall current, rotation and two temperatures. The model under assumption has been subjected to normal force. Laplace and Fourier transform have been used for finding the solution to the field equations. The analytical expressions for conductive temperature, stress components, normal current density, transverse current density and displacement components have been obtained in the physical domain using a numerical inversion technique. The effects of hall current and nonlocal parameter on resulting quantities have been depicted graphically. Some particular cases have also been figured out from the current work. The results can be very important for the researchers working in the field of magneto-thermoelastic materials, nonlocal thermoelasticity, geophysics etc.

Nonlocal thermo-electro-mechanical vibration analysis of smart curved FG piezoelectric Timoshenko nanobeam

  • Ebrahimi, Farzad;Daman, Mohsen
    • Smart Structures and Systems
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    • v.20 no.3
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    • pp.351-368
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    • 2017
  • To peruse the free vibration of curved functionally graded piezoelectric (FGP) nanosize beam in thermal environment, nonlocal elasticity theory is applied for modeling the nano scale effect. The governing equations are obtained via the energy method. Analytically Navier solution is employed to solve the governing equations for simply supported boundary conditions. Solving these equations enables us to estimate the natural frequency for curved FGP nanobeam under the effect of a uniform temperature change and external electric voltage. The results determined are verified by comparing the results by available ones in literature. The effects of various parameters such as nonlocality, uniform temperature changes, external electric voltage, gradient index, opening angle and aspect ratio of curved FGP nanobeam on the natural frequency are successfully discussed. The results revealed that the natural frequency of curved FGP nanobeam is significantly influenced by these effects.