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Damage and progressive failure of concrete structures using non-local peridynamic modeling

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Science china(Technological Sciences) 2011年第3期54卷 591-596页

作者： HUANG Dan1,2, ZHANG Qing1,2 & QIAO PiZhong1,3 1 State Key Laboratory of Hydrology-Water Resources and Hydraulic engineering, Hohai university, Nanjing 210098, china 2 department of engineering Mechanics, Hohai university, Nanjing 210098, china 3 department of Civil and Environmental engineering, Washington State university, Pullman, WA 99164-2910, USA 1. State Key Laboratory of Hydrology-Water Resources and Hydraulic engineering Hohai University Nanjing 210098 China2. Department of Engineering Mechanics Hohai University Nanjing 210098 China3. Department of Civil and Environmental Engineering Washington State University Pullman WA 99164-2910 USA

Peridynamics (PD), a recently developed theory of solid mechanics, which employs a non-local model of force interaction and makes use of integral formulation rather than the spatial partial differential equations used in the classical continuum mechanics theory, has shown effectiveness and promise in solving discontinuous problems at both macro and micro scales. In this paper, the peridynamics theory is used to analyze damage and progressive failure of concrete structures. A non-local peridynamic model for a rectangular concrete plate is developed, and a central pairwise force function is introduced to describe the interior interactions between particles within some definite distance. Damage initiation, evolution and crack propagation in the concrete model subject to in-plane uni-axial tension, in-plane uni-axial compression and out-of-plane impact load are investigated respectively. The numerical results show that discontinuities appear and grow spontaneously as part of the solution to the peridynamic equations of motion, and no special failure criteria or re-meshing techniques are required, which proves the potential of peridynamic modeling as a promising technique for analyzing the progressive failure of concrete materials and structures.

关键词： concrete damage progressive failure peridynamic model discontinuities

Numerical Simulation of Nonlinear Radiation Water Surface Wave Caused by Large-Amplitude Oscillation of A Cylinder

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Communications in Nonlinear Science and Numerical Simulation 1999年第1期4卷 24-28页

作者： Wuzhou HE (department of Hydraulic engineering, Tsinghua university, Beijing 100084, china) department of Hydraulic engineering Tsinghua University Beijing 100084 China

The BEM combined with the time-stepping scheme is employed in the nonlinear numerical simulation of the development process of radiation wave profile and hydrodynamic force caused by large amplitude oscillating cylinder. To ensure stability and accuracy of the simulation, special consideration is paid on a series of difficulties in numerical modeling, such as the compatibility of free surface and body surface conditions at the intersection point and the open boundary condition problem. Numerical calculation is carried out for some study cases of different shaped cylinders undergoing large amplitude oscillating motions with distinct modes, the results show. some nonlinear phenomena and indicate the feasibility of the numerical approach.

关键词： 2-D water surface wave boundary element method time-stepping scheme

Study on the thermal stability and electrical properties of the high-k dielectrics (ZrO_2) _x(SiO_2)_(1-x)

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Science china(Technological Sciences) 2009年第8期52卷 2222-2226页

作者： Lü ShiCheng1,2, YIN Jiang1,2, XIA YiDong2,3, GAO LiGang2,3 & LIU ZhiGuo2,3 1 department of Physics, Nanjing university, Nanjing 210093, china 2 National Laboratory of Solid Sate Microstructures, Nanjing university, Nanjing 210093, china 3 department of Materials Science and engineering, Nanjing university, Nanjing 210093, china 1. department of Physics Nanjing University Nanjing 210093 China 2. National Laboratory of Solid Sate Microstructures Nanjing University Nanjing 210093 China 3. department of Materials Science and engineering Nanjing University Nanjing 210093 China

(ZrO2)x(SiO2)1-x (Zr-Si-O) films with different compositions were deposited on p-Si(100) substrates by using pulsed laser deposition technique. X-ray photoelectron spectra (XPS) showed that these films remained amorphous after annealing at 800℃ with RTA process in N2 for 60 s. The XPS spectra indi- cated that Zr-Si-O films with x=0.5 suffered no obvious phase separation after annealing at 800℃, and no interface layer was formed between Zr-Si-O film and Si substrate. While Zr-Si-O films with x >0.5 suffered phase separation to precipitate ZrO2 after annealing under the same condition, and SiO2 was formed at the interface. To get a good interface between Zr-Si-O films and Si substrate, Zr-Si-O films with bi-layer structure (ZrO2)0.7(SiO2)0.3/(ZrO2)0.5(SiO2)0.5/Si was deposited. The electrical properties showed that the bi-layer Zr-Si-O film is of the lowest equivalent oxide thickness and good interface with Si substrate.

关键词： high-k dielectric film pulsed laser deposition pseudo ternary alloy

TEXTURE DETERMINATION OF THIN FILM ZrO_2 BY ELECTRON DIFFRACTION

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Acta Metallurgica Sinica(English Letters) 1993年第12期6卷 472-473页

作者： WANG Yinghua Tsinghua university,Beijing,china department of Materials Science and engineering,Tsinghua university,Beijing 100084,china Tsinghua Univ Beijing China

A method for semi-quantitative determination of thin film texture using electron diffrac- tion is *** texture state of a zirconia thin film with a cubic structure has been determined in this way and is presented as an... 详细信息

关键词： texture thin film electron diffraction ZrO_2

Surface investigation on Upilex-S polymide film iradiated by vacuum ultraviolet radiation

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Rare Metals 2007年第S1期26卷 168-174页

作者： LIU Yuyan1),GONG Xianyun2),WAN Zhimin3),and DU Xingwen4)1) department of Applied Chemistry,har.in Institute of Technology,har.in 150001,china 2) department of Life Science and Chemistry,har.in university,har.in 150001,china 3) Analysis and Measurement Center,har.in Institute of Technology,har.in 150001,china 4) Center for Composite Materials,har.in Institute of Technology,har.in 150001,china har.in Inst Technol Dept Appl Chem Harbin 150001 Peoples R China har.in Univ Dept Life Sci & Chem Harbin 150001 Peoples R China har.in Inst Technol Ctr Anal & Measurement Harbin 150001 Peoples R China har.in Inst Technol Ctr Composite Mat Harbin 150001 Peoples R China

Vacuum ultraviolet radiation of Upilex-S polyimide film 25 μm thick was performed using a gas jet type of vacuum ultraviolet simulator which gives unfixed wavelength from 5 nm to 200 *** redeposited on the films were observed and the nanoparticles formed on the surface consist mainly of carbon *** in the composition and the chemical characteristics of film surface after radiation were identified by X-ray photoelectron spectroscopy(XPS).Relative O content in the radiated area was found to be higher,while N content was lower than in the pristine *** indicates that Upilex-S polyimide film releases N atoms as volatile *** the C1s,O1s envelopes were fitted using Multipak Spectrum *** surface morphologies on iradiated area were examined by Atomic Force Microscope(AFM).Pieces of radiant products protrude from the eradiated surface,leading to considerable roughness for the iradiated *** the surface transmittance of Upilex-S film after radiation reduces.

关键词： vacuum ultraviolet radiation Upilex-S polyimide film

LINEAR ACTIVE STRUCTURES AND MODES (Ⅱ) —DISCRETE SYSTEMS AND BEAMS

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Applied Mathematics and Mechanics(English Edition) 2004年第8期25卷 854-862页

作者：王永刚龚靖School of Civil engineering and Mechanics Xi'an Jiaotong university Xi'an 710049 P.R.china department of Civil engineering northeast china Institute of Electric Power Jilin 132012 P.R.china 张景绘School of Civil engineering and Mechanics Xi'an Jiaotong university Xi'an 710049 P.R.china School of Civil engineering and Mechanics Xi'an Jiaotong University Xi'an 710049 P.R.ChinaSchool of Science Chang'an University Xi'an 710064 P.R.China

The basic concepts about the active structures and some attributes of the modes were presented in paper “Liner Active Structures and Modes]( I) ". The characteristics of the active discrete systems and active beams were discussed, especially, the stability of the active structures and the orthogonality of the eigenvectors. The notes about modes were portrayed by a model of a seven-storeyed building with sensors and actuators. The concept of the adjoint active structure was extended from the discrete systems to the beams that were the representations of the continuous structures. Two types of beams with different placements of the measuring and actuating systems were discussed in detail. One is the beam with the discrete sensors and actuators, and the other is the beam with distributed sensor and actuator function. The orthogonality conditions were derived with the modal shapes of the active beam and its adjoint active beam. An example shows that the variation of eigenvalues with feedback amplitude for the homo-configuration and non-homo-configuration active structures.

关键词： I) ". The characteristics of the active discrete systems and active beams were discussed especially the stability of the active structures and the orthogonality of the eigenvectors. The notes about modes were portrayed by a model of a seven-s

Relations Between Characteristic Function,Positive P-Representation and Coherent Thermal State

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Communications in Theoretical Physics 2007年第7期48卷 67-70页

作者： FAN Hong-Yi XU Xing-Lei department of Material Science and engineering,university of Science and Technology of china,Hefei 230026,china2 department of Physics,Shanghai Jiao Tong university,Shanghai 200030,china3 department of Physics,Heze university,Heze 274015,china department of Material Science and engineering University of Science and Technology of China department of Physics Shanghai Jiao Tong University department of Physics Heze University

We employ the coherent thermal states(a kind of entangled states)in thermal field dynamics to establisha complete entangled state formalism expressing pseudo-classical representations of density operator for light ***,the relationship between the coherent thermal state and the characteristic function and the positive Prepresentation in quantum optics theory are obtained.

关键词： coherent thermal state characteristic function positive P-representation

Effect of rare earths on phase transformation in as-cast ZA27 alloy dur-ing compressive creep

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Rare Metals 2003年第4期22卷 259-264页

作者： WEIXiaowei SHENBaoluo DepamnentofAppliedPhysics UniversityofElectronicScienceandTechnologyofChinaChengdu610045China DeparlanentofMetalScience SichuanUniversityChengdu610065China

The effect of the mixed rare earths of Ce on the phase transformation in ascast ZA 27 alloy during compressive was investigated under 37 MPa and at 160 deg C by X-raydiffraction technique and SEM. The results showed that the as cast microstructure of ZA 27-RE alloyconsisted of a dendritic Al-rich alpha' surrounded by Zn-rich beta' phase, interdendritic epsilonphase and Zn-rich eta phase together with a complex Z phase which was a complex constitute compound,(RE,Cu)Al_5Zn_(16), dispersed in crystal interfaces or branch crystal interfaces and stable duringcompressive creep test at 160 deg C. The phase transformations of ZA 27-RE alloy, decomposition ofbeta' phase arid four transformation, were delayed by the addition of rare earths, also the lamellarstructure and the spheroidized structure in ZA 27-RE alloy were finer than in ZA 27 alloy duringcompressive creep test at 160 deg C at the same creep time, and the compressive creep resistance ofZA 27-RE alloy was higher than that of ZA 27 alloy.

关键词： microstructure change compressive creep rare earths ZA 27 alloy

Parameter identification theory of a complex model based on global optimization method

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Science china(Physics,Mechanics & Astronomy) 2008年第11期51卷 1722-1732页

作者： QU Jie1, JIN QuanLin2 & XU BingYe3 1 College of Automotive engineering, South china university of Technology, Guangzhou 510640, china 2 Beijing Research Institute of Mechanical and Electrical Technology, Beijing 100083, china 3 department of engineering Mechanics, Tsinghua university, Beijing 100084, china 1. College of Automotive engineering South China University of Technology Guangzhou 510640 China 2. Beijing Research Institute of Mechanical and Electrical Technology Beijing 100083 China 3. department of engineering Mechanics Tsinghua University Beijing 100084 China

With the development of computer technology and numerical simulation technology, computer aided engineering (CAE) technology has been widely applied to many fields. One of the main obstacles, which hinder the further application of CAE technology, is how to successfully identify the parameters of the selected model. An elementary framework for parameter identification of a complex model is provided in this paper. The framework includes the construction of objective function, the design of the optimization method and the evaluation of the identified results, etc. The parameter identification process is described in this framework, taking the parameter identification of the superplastic constitutive model considering grain growth for Ti-6Al-4V at 927°C as an example. The objective function is the weighted quadratic sums of the difference between the experimental and computational data for the stress-strain relationship and the grain growth relationship; the designed optimization method is a hybrid global optimization method, which is based on the feature of the objective function and incorporates the strengths of genetic algorithm (GA), the Levenberg-Marquardt algorithm and the augmented Gauss-Newton algorithm. The reliability evaluation of parameter identification result is made through the comparison between the calculated and experimental results and between the theoretical values of the parameters and the identified ones.

关键词： constitutive model parameter identification theory inverse analysis global optimization