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Tensionless contact of a finite circular plate

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Acta Mechanica Sinica 2012年第5期28卷 1374-1381页

作者： Yin Zhang kevin D.murphy State Key Laboratory of Nonlinear Mechanics(LNM) Institute of MechanicsChinese Academy of Sciences Department of Mechanical Engineering the University of Connecticut

A general formulation is developed for the contact behavior of a finite circular plate with a tensionless elastic foundation. The gap distance between the plate and elastic foundation is incorporated as an important parameter. Unlike the previous models with zero gap distance and large/infinite plate radius, which assumes the lift-off/separation of a flexural plate from its supporting elastic foundation, this study shows that lift-off may not occur. The results show how the contact area varies with the plate radius, boundary conditions and gap distance. When the plate radius becomes large enough and the gap distance is reduced to zero, the converged contact radius close to the previous ones is obtained.

关键词： Tensionless contact Elastic foundation Plate Lift-off

Tensionless contact of a finite beam:Concentrated load inside and outside the contact zone

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Acta Mechanica Sinica 2013年第6期29卷 836-839页

作者： Yin Zhang kevin D.murphy State Key Laboratory of Nonlinear Mechanics Institute of MechanicsChinese Academy of Sciences Department of Mechanical Engineering University of ConnecticutStorrsCT 06268USA

For a finite beam with a nonzero gap distance, an asymmetric concentrated load can be either inside or outside of the contact zone. A new governing equation is given for the case of a concentrated load outside the contact zone. By numerically solving the left-side and right-side contact lengths of the beam, a criterion is established to determine whether the concentrated load is inside or outside the contact zone. A more general approach on the tensionless contact of a beam is thus presented.

关键词： Tensionless contact Lift-off Beam

CRACK PROPAGATION IN STRUCTURES SUBJECTED TO PERIODIC EXCITATION

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Acta Mechanica Solida Sinica 2007年第3期20卷 236-246页

作者： Zhang Yin murphy kevin D. State Key Laboratory of Nonlinear Mechanics （LNM） Institute of Mechanics Chinese Academy of Sciences Beijing 100080 China Department of Mechanical Engineering University of Connecticut CT 06269-3139 USA

In the present paper, asimple mechanical modelis developed to predict thedynamic response of a cracked structure subjected to periodic excitation, which has been used to identify the physical mechanisms in leading the growth or arrest of cracking. The structure under consideration consists of a beam with a crack along the axis, and thus, the crack may open in Mode I and in the axial direction propagate when the beam vibrates. In this paper, the system is modeled as a cantilever beam lying on a partial elastic foundation, where the portion of the beam on the foundation represents the intact portion of the beam. Modal analysis is employed to obtain a closed form solution for the structural response. Crack propagation is studied by allowing the elastic foundation to shorten （mimicking crack growth） if a displacement criterion, based on the material toughness, is met. As the crack propagates, the structural model is updated using the new foundation length and the response continues. From this work, two mechanisms for crack arrest are identified. It is also shown that the crack propagation is strongly influenced by the transient response of the structure.

关键词： crack propagation/arrest elastic foundation modal analysis vibration natural frequency

Nonlinear dynamic response of beam and its application in nanomechanical resonator

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Acta Mechanica Sinica 2012年第1期28卷 190-200页

作者： Yin Zhang Yun Liu kevin D.murphy State Key Laboratory of Nonlinear Mechanics Institute of MechanicsChinese Academy of Sciences100190 BeijingChina Faculty of Information and Automation Kunming University of Science and Technology650051 KunmingChina Department of Mechanical Engineering The University of ConnecticutStorrsCT 06269USA

Nonlinear dynamic response of nanomechanical resonator is of very important characteristics in its application. Two categories of the tension-dominant and curvaturedominant nonlinearities are analyzed. The dynamic nonlinearity of four beam structures of nanomechanical resonator is quantitatively studied via a dimensional analysis approach. The dimensional analysis shows that for the nanomechanical resonator of tension-dominant nonlinearity, its dynamic nonlinearity decreases monotonically with increasing axial loading and increases monotonically with the increasing aspect ratio of length to thickness; the dynamic nonlinearity can only result in the hardening effects. However, for the nanomechanical resonator of the curvature-dominant nonlinearity, its dynamic nonlinearity is only dependent on axial loading. Compared with the tension-dominant nonlinearity, the curvature-dominant nonlinearity increases monotonically with increasing axial loading; its dynamic nonlinearity

关键词： Resonator. Dynamic response. Dynamic nonlinearity - Dimensional analysis

BUCKLING LOADS AND EIGENFREQUENCIES OF A BRACED BEAM RESTING ON AN ELASTIC FOUNDATION

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Acta Mechanica Solida Sinica 2011年第6期24卷 510-518页

作者： Yin Zhang Yun Liu Peng Chen kevin D murphy State Key Laboratory of-Nonlinear Mechanics （LN M） Institute of Mechanics Chinese Academy of Sciences Beijing 100190 China Faculty of Information and Automation Kunming University of Science and Technology Kunming 650051 China Department of Civil Engineerning Guangdong Technical College of Water Resources and Electric Engineering Guangzhou 510635 China Department of Mechanical Engineering University of Connecticut Storrs CT 06269 USA

The eigenvalue problems of the buckling loads and natural frequencies of a braced beam on an elastic foundation are investigated. sented. The eigenvalues vary with the different The exact solutions for the eigenvalues are preparameters and are especially sensitive to the brace location. As the beam of a continuous system has infinite eigenvalues and these eigenvalues are influenced differently by a brace, the eigenvalues show rich variation patterns. Because these eigenvalues physically correspond to the structure buckling loads and natural frequencies, the study on the eigenvalues variation patterns can offer a design guidance of using a lateral brace of translation spring to strengthen the structure.

关键词： beam elastic foundation buckling eigenfrequency curve crossing curve veering

Selection,Installation and Use of Biological Safety Cabinets

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Selection,Installation and Use of Biological Safety Cabinets

Antitangling and manufacturable Fog Harps for high‐efficiency water harvesting

第三届全国临床检验实验室管理学术会议

作者： kevin murphy NuAire Eric Chan

来源： cnki会议 cnki会议评论

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Droplet 2023年第4期2卷 38-44页

作者： Jimmy K.Kaindu kevin R.murphy Nicholas G.Kowalski Alexandra N.Jones Matthew Davis Fleming Brook S.Kennedy Jonathan B.Boreyko Department of Mechanical Engineering Virginia TechBlacksburgVirginiaUSA Department of Biomedical Engineering and Mechanics Virginia TechBlacksburgVirginiaUSA School of Architecture and Design Virginia TechBlacksburgVirginiaUSA Samscreen Inc. ConklinNew YorkUSA

Fog Harps harvest substantially more water than conventional mesh‐based ***,to date,all large‐scale Fog Harps have been impractically hand‐wound at low wire tensions and suffer from elastocapillary wire ***,we develop large‐scale and high‐tension Fog Harps that are manufacturable and *** Fog Harps retain the record‐setting fog harvesting efficiency(η≈17%)of their optimized scale‐model counterparts,while uniquely enabling practical real‐life *** was achieved by adapting the industrial process for making harp screens,a pre‐existing technology used for screening solid *** critical tension required to minimize wire tangling was rationalized by an improved elastocapillary tangling model.

关键词： harvesting capillary rational

Erratum to:Tensionless contact of a finite circular plate

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Acta Mechanica Sinica 2013年第2期29卷 309-309页

作者： Yin Zhang kevin D. murphy State Key Laboratory of Nonlinear Mechanics (LNM) Institute of MechanicsChinese Academy of Sciences Department of Mechanical Engineering the University of Connecticut

In the electronic version of the original article, the issue number shown in the header of the article opening page was wrong. It should be Issue 5 as in Acta Mechanica Sinica (2012) 28(5): 1374-1381.

关键词： Erratum to

Computed tomography dose optimisation in cystic fibrosis:A review

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World Journal of Radiology 2016年第4期8卷 331-341页

作者： Helena Ferris Maria Twomey Fiachra Moloney Siobhan B O'Neill kevin murphy Owen J O'Connor Michael Maher Department of Radiology Cork University Hospital

Cystic fibrosis(CF)is the most common autosomal recessive disease of the Caucasian population worldwide,with respiratory disease remaining the most relevant source of morbidity and *** tomography(CT)is frequently used for monitoring disease complications and *** the last fifteen years there has been a six-fold increase in the use of CT,which has lead to a growing concern in relation to cumulative radiation *** challenge to the medical profession is to identify dose reduction strategies that meet acceptable image quality,but fulfil the requirements of a diagnostic quality ***-optimisation,particularly in CT,is essential as it reduces the chances of patients receiving cumulative radiation doses in excess of 100 m Sv,a dose deemed significant by the United Nations Scientific Committee on the Effects of Atomic *** review article explores the current trends in imaging in CF with particular emphasis on new developments in dose optimisation.

关键词： Cystic fibrosis Dose optimization Computed tomography Dose Ionising radiation Kalydeco