检索结果-南通市图书馆

Acta Mechanica Sinica 2015年第5期31卷 601-626页

作者： wei-qiu chen Department of Engineering Mechanics Zhejiang University

Significant progress has been made in mixed boundary-value problems associated with three-dimensional（3D） crack and contact analyses of advanced materials featuring more complexities compared to the conventional isotropic elastic *** include material anisotropy and multifield coupling,two typical characteristics of most current multifunctional *** this paper we try to present a state-of-the-art description of 3D exact/analytical solutions derived for crack and contact problems of elastic solids with both transverse isotropy and multifield coupling in the latest decade by the potential theory method in the spirit of *** ingenious breakthrough brings new vigor and vitality to the old research subject of classical potential *** are particularly interested in crack and contact problems with certain nonlinear *** is also placed on the coupling between the temperature field（or the like） and other physical fields（e.g.,elastic,electric,and magnetic fields）.We further highlight the practical significance of 3D contact solutions,in particular in applications related to modern scanning probe microscopes.

关键词： Crack Contact Mixed boundary-value problem Transverse isotropy Multifield coupling Potential theory Exact solution Scanning probe microscope

Analysis of the penalty version of the Arlequin framework for the prediction of structural responses with large deformations

在线全文

学校读者我要写书评

暂无评论

Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2011年第7期12卷 552-560页

作者： Hua QIAO wei-qiu chen Department of Engineering Mechanics Zhejiang University Hangzhou 310027 China

The Arlequin framework proposed by Ben Dhia in 1998 is a flexible and robust method for conducting global/local analysis of structures and materials.A penalty version of the Arlequin framework for the study of structural problems involving large deformation is considered *** implementation of the penalty-based Arlequin framework into ABAQUS is then explored and the corresponding Arlequin user element subroutine is *** nonlinear simulations of a cantilever beam and a shallow arch are conducted and the choice of the coupling operator with an appropriate penalty parameter is *** numerical results justify the feasibility of the proposed method,ensuring its further application to more complicated problems involving geometric or material nonlinearities.

关键词： Global/Local analysis Geometric nonlinear analysis Penalty-based Arlequin method User defined element

Science Letters:On numerical calculation in symplectic approach for elasticity problems

在线全文

学校读者我要写书评

暂无评论

Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2008年第5期9卷 583-588页

作者： Li ZHAO wei-qiu chen Department of Civil Engineering Zhejiang University Hangzhou 310027 China

The symplectic approach proposed and developed by Zhong et al. in 1990s for elasticity problems is a rational analytical method, in which ample experience is not needed as in the conventional semi-inverse method. In the symplectic space, elasticity problems can be solved using the method of separation of variables along with the eigenfunction expansion technique, as in traditional Fourier analysis. The eigensolutions include those corresponding to zero and nonzero eigenvalues. The latter group can be further divided into α-and β-sets. This paper reformulates the form of β-set eigensolutions to achieve the stability of numerical calculation, which is very important to obtain accurate results within the symplectic frame. An example is finally given and numerical results are compared and discussed.

关键词： Symplectic approach Eigenfunction Numerical stability Elasticity problems

Modeling of sensor function for piezoelectric bender elements

在线全文

学校读者我要写书评

暂无评论

Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2008年第1期9卷 1-7页

作者： Yan-guo ZHOU Yun-min chen Hao-jiang DING wei-qiu chen Key Laboratory of Soft Soils and Geoenvironmental Engineering Ministry of Education Zhejiang University Hangzhou 310027 China

An analytical sandwich beam model for piezoelectric bender elements is derived based on the first-order shear deformation theory (FSDT), which assumes a single rotation angle for the whole cross-section and a quadratic distribution for coupled electric potential in piezoelectric layers. Shear coefficient is introduced to correct the effect of transverse shear strain on shear force and the electric displacement integration. Static and free vibration analyses of simply-supported bender elements are carried out for the sensor function. The results illustrate the high accuracy of the present model compared with the exact 2D solutions.

关键词： Bender elements Piezoelectric Sensor Sandwich beam Shear coefficient

Robustly Tuning Bandgaps in Two-Dimensional Soft Phononic Crystals with Criss-Crossed Elliptical Holes

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Solida Sinica 2018年第5期31卷 573-588页

作者： Nan Gao Yi-lan Huang Rong-hao Bao wei-qiu chen Department of Engineering Mechanics Zhejiang University Hangzhou 310027 China State Key Lab of CAD & CG Zhejiang University Hangzhou 310058 China Key Laboratory of Soft Machines and Smart Devices of Zhejiang Province Zhejiang University Hangzhou 310027 China Soft Matter Research Center Zhejiang University Hangzhou 310027 China

Tuning band gaps in soft materials by post-buckling deformation is becoming an appealing means to manipulate elastic waves. As one of the most favorable topologies, two- dimensional soft structures with circular holes have been extensively studied. Based on the contrarian thinking, this paper starts from the two-dimensional soft structures with criss-crossed elliptical holes, which is close to the post-buckling configuration of soft structures with circular holes, and then proposes to tune the band gaps through elongating or stretching rather than compressing. Influences of the loading magnitude and loading pattern （i.e., uniaxial and biaxial elongations） on the band gaps are studied via the nonlinear finite element simulations. Effects of the geometric parameters （the major-to-minor half-axis ratio and the porosity of the structure） are also discussed. It is shown that, compared with the traditional circular hole case, the band gaps of the unloaded structure with criss-crossed elliptical holes are much richer, and they could be reversely and continuously tuned by tensile loadings. In particular, the deformation is very robust and is insensitive to small geometric imperfections, which is always necessary for triggering the post-buckling deformations. The present work provides a useful reference to the manipula- tion of elastic waves in periodic structures as well as the design of soft phononic crystals/acoustic devices.

关键词： Soft phononic crystal Criss-crossed elliptical holes Band gap Tunability

Indentation of a compressible soft electroactive half-space: Some theoretical aspects

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta Mechanica Sinica 2012年第4期28卷 1133-1142页

作者： Wen-Liang Zhang Jin Qian wei-qiu chen Soft Matter Research Center(SMRC) Zhejiang University310027 HangzhouChina Department of Engineering Mechanics Zhejiang University310027 HangzhouChina

We theoretically study the indentation response of a compressible soft electroactive material by a rigid punch. The half-space material is assumed to be initially subjected to a finite deformation and an electric biasing field. By adopting the linearized theory for incremental fields, which is established on the basis of a general nonlinear theory for electroelasticity, the appropriate equations governing the perturbed infinitesimal elastic and electric fields are derived particularly when the material is subjected to a uniform equibiaxial stretch and a uniform electric displacement. A general solution to the governing equations is presented, which is concisely expressed in terms of four quasi-harmonic functions. By adopting the potential theory method, exact contact solutions for three common perfectly conducting rigid indenters of fiat-ended circular, conical and spherical geometries can be derived, and some explicit relations that are of practical importance are outlined.

关键词： Soft electroactive material Finite pre-stretch Indentation Contact analysis Exact solution

Micromechanics-based analysis for predicting asphalt concrete modulus

在线全文

学校读者我要写书评

暂无评论

Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2010年第6期11卷 415-424页

作者： Xing-yi ZHU Zhi-yi HUANG Zhong-xuan YANG wei-qiu chen Department of Civil Engineering Zhejiang University Hangzhou 310058 China Department of Engineering Mechanics Zhejiang University Hangzhou 310027 China

The elastic modulus of asphalt concrete(AC) is an important material parameter for pavement *** prediction and determination of elastic modulus,however,largely depends on laboratory tests which cannot reflect explicitly the influence of the microstructure of *** this end,a micromechanical model based on stepping scheme is *** is given to the influence of interfacial debonding and interlocking effect between the aggregates and asphalt mastic using the concept of effective *** on asphalt mixture with various microstructures are conducted to verify the proposed *** is shown that the prediction is generally in agreement with experimental *** affecting the elastic modulus of AC are also discussed in light of the proposed method.

关键词： Asphalt concrete(AC) Micromechanics Microstructure Effective bonding Optimum design Elastic modulus

The renaissance of continuum mechanics

在线全文

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

Corrosion and wear properties of in situ(TiB+TiC)/TA15 composites with a high volume percentage of reinforcement

在线全文

学校读者我要写书评

暂无评论

China Foundry 2023年第5期20卷 423-431页

作者： wei-long Wang Kun Shi Jun Zhao Shi-bing Liu Jiao-jiao cheng wei-chen qiu Tian-yu Liu Zhi-yong Zhang Shenyang Research Institute of Foundry Co. Ltd.CAMShenyang 110022China National Key Laboratory of Advanced Casting Technologies Shenyang 110022China

The in situ(TiC+TiB)/TA15 composites with different volume percentages of reinforcement(10%,15%,20%and 25%)were prepared by water-cooled copper crucible vacuum suspension melting *** structures and compositions of the TA15 alloy and its composites were analyzed by XRD and EDS,and their electrochemical corrosion behaviors in the 3.5%NaCl solution were *** wear testing was conducted using a reciprocating ball-on-disc wear tester under a 10 N *** show that the in situ fibrous TiB phase and the granular TiC phase are uniformly distributed on the composite *** microhardness can reach up to 531 HV as 25vol.%TiC+TiB reinforcement is *** with the TA15 alloy,the volume wear rate decreases from(2.21±0.07)×10^(-4)to(1.75±0.07)×10^(-4)mm^(3)·N^(-1)·m^(-1)by adding 15vol.%TiC+TiB reinforcement,and the wear mechanism is adhesive *** the volume percentage of the reinforcement phase reaches 25%,the volume wear rate increases from(1.75±0.07)×10^(-4)to(2.41±0.07)×10^(-4)mm^(3)·N^(-1)·m^(-1),and the wear mechanism changes into abrasive *** volume loss resulted by the interaction between corrosion and wear accounts for more than 27%of the total wear *** volume loss due to wear-induced corrosion changes from 1.94%to 4.06%with different additions of *** volume loss caused by corrosion-induced wear initially increases from 24.08%to 26.90%as the reinforcement increases from 0 to 15%due to the increase of corrosion potential,and then decreases from 26.90%to 25.68%as the reinforcement increases from 15%to 25%due to the peeling of TiC phase.

关键词： titanium matrix composites high volume percentage corrosion wear wear mechanism

Numerical studies on issues of Re-independence for indoor airflow and pollutant dispersion within an isolated building

在线全文

学校读者我要写书评

暂无评论

Building Simulation 2022年第7期15卷 1259-1276页

作者： Peng-Yi Cui wei-qiu chen Jia-Qi Wang Jin-Hao Zhang Yuan-Dong Huang Wen-Quan Tao College of Environment and Architecture University of Shanghai for Science and TechnologyShanghaiChina Key Laboratory of Thermo-Fluid Science and Engineering of MOE School of Energy and Power EngineeringXi'an Jiaotong UniversityXi’anChina

This study conducted the numerical models validated by wind-tunnel experiments to investigate the issues of Re-independence of indoor airflow and pollutant dispersion within an isolated *** window Reynolds number(Re_(w))was specified to characterize the indoor flow and *** indicators of RRC(ratio of relative change)or DR(K_DR)(difference ratio of dimensionless concentration)<5%were applied to quantitatively determine the critical Rew for indoor flow and turbulent *** results show that the critical Re(Re_(crit)) value is position-dependent,and Re_(crit) at the most unfavorable position should be suggested as the optimal value within the whole areas of *** Re(H,orit)=27,000 is recommended for the outdoor flows;while Re_(w,crit)=15,000 is determined for the indoor flows due to the lower part below the window showing the most *** suggested Re_(w,crit)(=15,000)for indoor airflow and cross ventilation is independence of the window ***,taking K_DR≤5% as the indicator,the suggested Re_(w,crit) for ensuring indoor pollutant diffusion enter the independence regime should also be 15,000,indicating that indoor passive diffusion is completely determined by the flow *** contours of dimensionless velocity(U/U_(0))and concentration(K)against the increasing Re(w) further confirmed this critical *** study further reveals the Re-independence issues for indoor flow and dispersion to ensure the reliability of the data obtained by reduced-scale numerical or wind-tunnel models.

关键词： CFD simulation Re-independence similarity criterion indoor ventilation pollutant dispersion