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The influence of defects on the effective Young's modulus of a defective solid

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Chinese Physics B 2013年第4期22卷 307-311页

作者：沈伟范群波王富耻马壮 Central Iron and Steel Research Institute School of Materials Science and Engineering Beijing Institute of Technology

It is difficult to establish structure-property relationships in a defective solid because of its inhomogeneous-geometry microstructure caused by defects. In the present research, the effects of pores and cracks on the Young’s modulus of a defective solid are studied. Based on the law of the conservation of energy, mathematical formulations are proposed to indicate how the shape, size, and distribution of defects affect the effective Young’s modulus. In this approach, detailed equations are illustrated to represent the shape and size of defects on the effective Young’s modulus. Different from the results obtained from the traditional empirical analyses, mixture law or statistical method, for the first time, our results from the finite element method （FEM） and strict analytical calculation show that the influence of pore radius and crack length on the effective Young’s modulus can be quantified. It is found that the longest crack in a typical microstructure of ceramic coating dominates the contribution of the effective Young’s modulus in the vertical direction of the crack.

关键词： defects effective Young’s modulus conservation of energy pore radius and crack length

energy Principle of Corrosion Environment Accelerating Crack Propagation During Anodic Dissolution Corrosion Fatigue

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Journal of Shanghai Jiaotong university(Science) 2013年第2期18卷 190-196页

作者：黄小光许金泉冯淼林 School of Navel Architecture Ocean and Civil EngineeringShanghai Jiaotong University College of Pipeline and Civil Engineering China University of Petroleum

A general method to predict the crack propagation of anodic dissolution corrosion fatigue is developed in this paper. Crack propagation of corrosion fatigue is presented as the result of the synergistic interactions of mechanical and environmental factors, and corrosive environment accelerates crack propagation mainly in term of anodic dissolution. By studying the variation of mechanical energy and electrochemical energy of anodic dissolution during the crack propagation process, an explicit expression of crack propagation rate is derived by the conservation of energy. The comparisons with experimental data demonstrate the validity of the proposed model. Moreover, the applicable upper-limit crack length for steady crack propagation is determined and the crack propagation life is evaluated.

关键词： crack propagation corrosion fatigue conservation of energy anodic dissolution

An efficient time-integration method for nonlinear dynamic analysis of solids and structures

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Science China(Physics,Mechanics & Astronomy) 2013年第4期56卷 798-804页

作者： LIU TianYun LI QingBin ZHAO ChongBin State Key Laboratory of Hydro-Science and Engineering Tsinghua University Computational Geosciences Research Centre Central South University

This paper presents an efficient time-integration method for obtaining reliable solutions to the second-order nonlinear dynamic problems in structural engineering. This method employs both the backward-acceleration differentiation formula and the trapezoidal rule, resulting in a self-starting, single step, second-order accurate algorithm. With the same computational effort as the trapezoidal rule, the proposed method remains stable in large deformation and long time range solutions even when the trapezoidal rule fails. Meanwhile, the proposed method has the following characteristics: (1) it is applicable to linear as well as general nonlinear analyses; (2) it does not involve additional variables (e.g. Lagrange multipliers) and artificial parameters; (3) it is a single-solver algorithm at the discrete time points with symmetric effective stiffness matrix and effective load vectors; and (4) it is easy to implement in an existing computational software. Some numerical results indicate that the proposed method is a powerful tool with some notable features for practical nonlinear dynamic analyses.

关键词： two-order system conservation of energy backward differentiation formula Newmark method nonlinear dynamics unconditional stability direct time integration

The Total energy in the Interaction of X-Ray Photons with Capacitors

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World Journal of Condensed Matter Physics 2020年第4期10卷 159-177页

作者： S. I. Hassan G. Scarel Department of Physics and Astronomy James Madison University Harrisonburg VA USA

Context and Background: In this research, we investigate the interaction of X-rays with a capacitor by studying the voltage established in the capacitor during the illumination. Motivation: We aim at verifying that the total energy conserved in the interaction is Pτ, i.e. the product of the average power P times the period τ of the X-rays. Hypothesis: Our investigation relies on the hypothesis that the voltage responsivity πV of the capacitor should be small, according to previous research. The parameter πV is the ratio between the voltage produced and the average power P of the X-rays, and measures the performance of the capacitor in response to the X-rays. Method: We measure the voltage produced by the capacitor in response to the X-rays, and then determine the average power P of the X-rays according to a procedure already assessed with infrared and visible light. Results: In our experiments, P turns out to be in the range between 10-3 W to 100 W. Our procedure enables us to unveil the relationship between the average power P and the effective dose, an i

关键词： X-Rays Power Light-Matter Interaction conservation of energy

Probing the Wave Nature of Light-Matter Interaction

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World Journal of Condensed Matter Physics 2018年第2期8卷 62-89页

作者： D.E.Boone C.H.Jackson A.T.Swecker J.S.Hergenrather K.S.Wenger O.Kokhan B.Terzic I.Melnikov I.N.Ivanov E.C.Stevens G.Scarel College of Integrated Science and Engineering James Madison UniversityHarrisonburgVirginiaUSA Department of Physics and Astronomy James Madison UniversityHarrisonburgVAUSA Department of Chemistry and Biochemistry James Madison UniversityHarrisonburgVAUSA Department of Physics Old Dominion UniversityNorfolkVAUSA Center for Nanophase Materials Sciences Oak Ridge National LaboratoryOak RidgeTNUSA Department of Chemical and Biomolecular Engineering North Carolina State UniversityCentennial CampusRaleighNCUSA

The wave-particle duality of light is a controversial topic in modern physics. In this context, this work highlights the ability of the wave-nature of light on its own to account for the conservation of energy in light-matter interaction. Two simple fundamental properties of light as wave are involved: its period and its power P. The power P depends only on the amplitude of the wave’s electric and magnetic fields (Poynting’s vector), and can easily be measured with a power sensor for visible and infrared lasers. The advantage of such a wave-based approach is that it unveils unexpected effects of light’s power P capable of explaining numerous results published in current scientific literature, of correlating phenomena otherwise considered as disjointed, and of making predictions on ways to employ the electromagnetic (EM) waves which so far are unexplored. In this framework, this work focuses on determining the magnitude of the time interval that, coupled with light’s power P, establishes the energy conserved in the exchange of energy between light and matter. To reach this goal, capacitors were excited with visible and IR lasers at variable average power P. As the result of combining experimental measurements and simulations based on the law of conservation of energy, it was found that the product of the period of the light by its power P fixes the magnitude of the energy conserved in light’s interaction with the capacitors. This finding highlights that the energy exchanged is defined in the time interval equal to the period of the light’s wave. The validity of the finding is shown to hold in light’s interaction with matter in general, e.g. in the photoelectric effect with x-rays, in the transfer of electrons between energy levels in semiconducting interfaces of field effect transistors, in the activation of photosynthetic reactions, and in the generation of action potentials in retinal ganglion cells to enable vision in vertebrates. Finally, the validity of the find

关键词： Infrared Light-Matter Interaction conservation of energy Wave energy Harvesting