检索结果-南通市图书馆

A Hybrid Local/Nonlocal continuum mechanics Modeling of Damage and Fracture in Concrete Structure at High Temperatures

在线全文

学校读者我要写书评

暂无评论

Computer Modeling in Engineering & Sciences 2022年第11期133卷 389-412页

作者： Runze Song Fei Han Yong Mei Yunhou Sun Ao Zhang Department of Engineering mechanics State Key Laboratory of Structural Analysis for Industrial EquipmentInternational Research Center for Computational MechanicsDalian University of TechnologyDalian116023China Institute of Defense Engineering AMSBeijing100036China

This paper proposes a hybrid peridynamic and classical continuum mechanical model for the high-temperature damage and fracture analysis of concrete *** this model,we introduce the thermal expansion into peridynamics and then couple it with the thermoelasticity based on the Morphing *** addition,a thermomechanical constitutive model of peridynamic bond is presented inspired by the classic Mazars model for the quasi-brittle damage evolution of concrete structures under high-temperature *** validity and effectiveness of the proposed model are verified through two-dimensional numerical examples,in which the influence of temperature on the damage behavior of concrete structures is ***,the thermal effects on the fracture path of concrete structures are analyzed by numerical results.

关键词： Peridynamics continuum mechanics damage and fracture concrete structure thermoelasticity

continuum mechanics of Space Seen from the Aspect of General Relativity An Interpretation of the Gravity Mechanism

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Earth Science and Engineering 2015年第3期5卷 188-202页

作者： Yoshinari Minami Advanced Science-Technology Research Organization (Formerly NEC Space Development Division) Yokohama 220-0062 Japan

A mechanical structure of space is suggested. On the supposition that a space as vacuum has a physical fine structure like continuum, it enables us to apply a continuum mechanics to the so-called ＂vacuum＂ of space. A space is an infinite continuum and its structure is determined by Riemannian geometry. Assuming that space is an infmite continuum, the pressure field derived from the geometrical structure of space is newly obtained by applying both continuum mechanics and General Relativity to space. A fundamental concept of space-time is described that focuses on theoretically innate properties of space including strain and curvature. As a trial consideration, gravity can be explained as a pressure field induced by the curvature of space.

关键词： General Relativity continuum mechanics curvature strain space-time gravity.

The renaissance of continuum mechanics

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2014年第4期15卷 231-240页

作者： Wei-qiu CHEN Department of Engineering mechanics Zhejiang University Hangzhou 310027 China

continuum mechanics, just as the name implies, deals with the mechanics problems of all continua, whose physical （or mechanical） properties are assumed to vary continuously in the spaces they occupy. continuum mechanics may be seen as the symbol of modem mechanics, which differs greatly from current physics, the two often being mixed up by people and even sci- entists. In this short paper, I will first try to give an illustration on the differences between （modem） mechanics and physics, in my personal view, and then focus on some important current research activities in continuum mechanics, attempting to identify its path to the near future. We can see that continuum mechanics, while having a dominating impact on engineering design in the 20th century, also plays a pivotal role in modem science, and is much closer to physics, chemistry, biology, etc. than ever before.

关键词： continuum mechanics Quantum mechanics Engineering Current research activities Renaissance

Trans-scale mechanics: looking for the missing links between continuum and micro/nanoscopic reality

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Sinica 2008年第2期24卷 111-126页

作者： Y.L.Bai H.Y.Wang M.F.Xia F.J.Ke State Key Laboratory of Non-linear mechanics (LNM) Institute of Mechanics Chinese Academy of Sciences Beijing 100080 China State Key Laboratory of Non-linear mechanics (LNM) Institute of Mechanics Chinese Academy of Sciences Beijing 100080 China Department of Physics Peking University Beijing 100871 China State Key Laboratory of Non-linear mechanics (LNM) Institute of Mechanics Chinese Academy of Sciences Beijing 100080 China Department of Applied Physics Beihang University Beijing 100083 China

Problems involving coupled multiple space and time scales offer a real challenge for conventional frame-works of either particle or continuum mechanics. In this paper, four cases studies （shear band formation in bulk metallic glasses, spallation resulting from stress wave, interaction between a probe tip and sample, the simulation of nanoindentation with molecular statistical thermodynamics） are provided to illustrate the three levels of trans-scale problems （problems due to various physical mechanisms at macro-level, problems due to micro-structural evolution at macro/micro-level, problems due to the coupling of atoms/ molecules and a finite size body at micro/nano-level） and their formulations. Accordingly, non-equilibrium statistical mechanics, coupled trans-scale equations and simultaneous solutions, and trans-scale algorithms based on atomic/molecular interaction are suggested as the three possible modes of trans-scale mechanics.

关键词： Multi-scale Missing-links continuum mechanics Particle mechanics Trans-scale mechanics

Conversion between solid and beam element solutions of finite element method based on meta-modeling theory:development and application to a ramp tunnel structure

在线全文

学校读者我要写书评

暂无评论

Earthquake Engineering and Engineering Vibration 2017年第2期16卷 297-309页

作者： JASC Jayasinghe M. Hori MR Riaz MLL Wijerathne T Ichimura Earthquake Research Institute University of Tokyo Tokyo 113-0032 Japan

In this study, a new method for conversion of solid finite element solution to beam finite element solution is developed based on the meta-modeling theory which constructs a model consistent with continuum mechanics. The proposed method is rigorous and efficient compared to a typical conversion method which merely computes surface integration of solid element nodal stresses to obtain cross-sectional forces. The meta-modeling theory ensures the rigorousness of proposed method by defining a proper distance between beam element and solid element solutions in a function space of continuum mechanics. Results of numerical verification test that is conducted with a simple cantilever beam are used to find the proper distance function for this conversion. Time history analysis of the main tunnel structure of a real ramp tunnel is considered as a numerical example for the proposed conversion method. It is shown that cross-sectional forces are readily computed for solid element solution of the main tunnel structure when it is converted to a beam element solution using the proposed method. Further, envelopes of resultant forces which are of primary importance for the purpose of design, are developed for a given ground motion at the end.

关键词： meta-modeling theory finite element method solid and beam element models continuum mechanics structural mechanics

Effects of Pairing Correlations on Formation of Proton Halo in 9C

在线全文

学校读者我要写书评

暂无评论

Chinese Physics Letters 2010年第9期27卷 61-64页

作者：韩瑞李加兴尧江明姬娟霞王建松胡强 School of Physical Science and Technology Southwest University Chongqing 400715 Institute of Modern Physics Chinese Academy of Science Lanzhou 730000

Properties for the ground state of 9 C are studied in the relativistic continuum Hartree-Bogoliubov theory with the NLSH, NLLN and TM2 effective interactions. Pairing correlations are taken into account by a density-dependent δ-force with the pairing strength for protons determined by fitting either to the experimental binding energy or to the odd-even mass difference from the five-point formula. The effects of pairing correlations on the formation of proton halo in the ground state of 9C are examined. The halo structure is shown to be formed by the partially occupied valence proton levels p3/2 and p1/2.

关键词： PAIRING correlations (Nuclear physics) PROTONS RELATIVISTIC mechanics continuum mechanics BINDING energy FORCE & energy

Is Brenner＇s Modification to the Classical Navier-Stokes Equations Able to Describe Sound Propagation in Gases？

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics Letters 2008年第4期25卷 1355-1358页

作者： W. Marques Jr. Departamento de Fisica Universidade Federal do Parana Calxa Postal 19044 81531-990 Curitiba Brazil

We analyse the problem concerning the propagation of sound waves in gases by using the modified hydrodynamic theory proposed recently by Brenner for single-component fluids. The modifications introduced by Brenner are based on his proposal that the translational momentum in fluid motion is not given by the mass flux. Comparison of the sound propagation results derived from Brenner＇s theory with available experimental data for monatomic gases shows that this modified continuum theory is unable to describe the acoustic measurements not even in the low-frequency limit, a result that from our point of view makes Brenner＇s proposal questionable.

关键词： NAVIER-Stokes equations PARTIAL differential equations FLUID dynamics continuum mechanics

Lie symmetry and Mei conservation law of continuum system

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics B 2011年第2期20卷 195-199页

作者：施沈阳傅景礼 Department of Physics Zhejiang Sci-Tech University

Lie symmetry and Mei conservation law of continuum Lagrange system are studied in this *** equation of motion of continuum system is established by using variational principle of continuous *** invariance of the equation of motion under an infinitesimal transformation group is determined to be *** condition of obtaining Mei conservation theorem from Lie symmetry is also *** example is discussed for applications of the results.

关键词： continuum mechanics Lie symmetry Mei symmetry conservation law

Suppercontinuum Generation in InP Nano Inner Cladding Fibers

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics Letters 2010年第5期27卷 142-143页

作者：段予文张茹王瑾陈曦钟昆 School of Sciences Beijing University of Posts and Telecommunications Beijing 100876 School of Ethnic Education Beijing University of Posts and Telecommunications Beijing 100876

The InP nano inner cladding fiber is fabricated by the method of modified chemical vapor deposition. The thickness of the InP nano thin film is about 16 nm. A 20 dB supercontinuum over 100nm in the telecommunication band is generated by infecting 1550nm, 120fs, 50MHz repetition rate optical pulse into this kind of fiber. Moreover, the results indicate that the width of the supercontinuum spectra can be influenced by the fiber length and pump power. The longer fiber at higher pump power can produce broader supercontinuum spectrum.

关键词： continuum mechanics INDIUM phosphide NANOSTRUCTURED materials METAL cladding MICROFABRICATION CHEMICAL vapor deposition TELECOMMUNICATION SPECTRUM analysis