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Snap-through of an elastica under bilateral displacement control at a material point

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Acta Mechanica Sinica 2020年第3期36卷 727-734页

作者： q.Wang H.l.Zou Z.C.Deng Department of Engineering Mechanics Northwestern Polytechnical UniversityXi'an 710072China

Snap-through phenomenon widely occurs for elastic systems,where the systems lose stability at critical *** snapthrough of an elastica under bilateral displacement control at a material point is studied,by regarding the whole elastica as two components,i.e.,pinned-clamped ***,stiffness-curvature curves of two pinned-clamped elasticas are firstly efficiently located based on the second-order mode,which are used to determine the shapes of two *** transformations are used to assemble two components together to form the whole elastica,which reveals four kinds of *** advantage of this way compared with other methods such as the shooting method is that multiple coexisting solutions can be located accurately.O n the load-deflection curves,four branches correspond to four kinds of shapes and first two branches are symmetrical to the last two branches relative to the original *** the bilateral displacement control,the critical points can only appear at saddle-node bifurcations,which is different to that for the unilateral displacement ***,one critical point is found on the first branch and two critical points are found on the secondary *** addition,the snap-through among different branches can be well explained with these critical points.

关键词： Elastica Snap-through Critical points Buckling Displacement control

A brief review：experimental investigation of zonal flows and geodesic acoustic modes in fusion plasmas

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Plasma Science and Technology 2018年第9期20卷 72-84页

作者： K J ZHAO J q DONG J q lI l W YAN Southwestern Institution of Physics Chengdu 610041People＇s Republic of China

Zonal flows self-generated by turbulence play an important role in regulating turbulence,reducing transport level,and thus improve plasma confinement in fusion *** zonal flows and geodesic acoustic modes have been identified in various *** related issues,such as the poloidal and toroidal symmetries,coupling to turbulence,effects on turbulence and transport,nonlinear energy transfer between turbulence and zonal flows,dependence of the plasma parameters,roles in the confinement regime transitions etc are overviewed briefly in this *** interaction between zonal flows and magnetic islands is emphasized.

关键词： zona flow tokamak turbulence fusion plasma

Spalling characteristics of high-temperature treated granitic rock at different strain rates

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第4期16卷 1280-1288页

作者： l.F.Fan q.H.Yang X.l.Du The Key laboratory of Urban Security and Disaster Engineering of Ministry of Education Beijing University of TechnologyBeijing100124China

The dynamic spalling characteristics of rock are important for stability analysis in rock *** paper presented an experimental investigation on the dynamic spalling characteristics of granite with different temperatures and strain rates.A series of dynamic spalling tests with different impact velocities were conducted on thermally treated granite at different *** dynamic spalling strengths of granite with different temperatures and strain rates were determined.A model was proposed to correlate the dynamic spalling strength of granite,high temperature and strain *** results show that the spalling strength of granite decreases with increasing ***,the spalling strength of granite with a higher strain rate is larger than that with a lower strain *** proposed model can describe the relationship among dynamic spalling strength of granite,high temperature and strain rate.

关键词： Dynamic spalling characteristics High temperature Strain rate Dynamic loading Granite

Multi-scale simulation of columnar-to-equiaxed transition during laser selective melting of rare earth magnesium alloy

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Journal of Materials Science & Technology 2022年第24期119卷 11-24页

作者： W.l.Wang W.q.liu X.Yang R.R.Xu q.Y.Dai School of Metallurgical Engineering Xi’an University of Architecture and TechnologyXi’an 710055China

A model of coupling macro finite volume method(FVM) and cellular automata(CA) is proposed in this paper to explore the columnar-to-equiaxed transition(CET) during selective laser melting(SlM) of rare earth magnesium *** into account the impact of recoil pressure and Marangoni convection on the molten pool temperature field,the grain structure is *** suggested by the simulation results,with the undissolved Zr serving as heterogeneous nucleation sites,the liquid undercooled layer under the combined action of forced cooling,the temperature gradient and the liquid solute concentration gradient leads to *** considering the dissolution of Zr in magnesium matrix,the results demonstrate that the dissolution of element Zr is effective in significantly inhibiting the growth of columnar crystals and ensuring the sufficient constitutional supercooling(CS) required for *** addition,to raise the preheating temperature contributes to enhancing the outcome of nucleation and incresing the grain *** the interdependence model(IM),with the cooling rate gradually increasing in the SlM process of magnesium alloy,the nucleation-free zone(NFZ) reduces by decreasing the solute diffusion layer in the front of the solid/liquid(Sl) interface and the temperature *** reduction in temperature gradient can promote undercooling for nucleation and facilitate the development of equiaxed *** simulation results are qualitatively verified as highly consistent through experimentation.

关键词： Multi-scale simulation Columnar-to-equiaxed transition Selective laser melting Rare earth magnesium alloy Constitutional supercooling

EXPERIMENTAl RESEARCH AND NUMERICAl SIMUlATION OF lASER SHOCK FORMING OF TA2 TITANIUM SHEET

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Acta Metallurgica Sinica(English letters) 2006年第5期19卷 347-354页

作者： F. Wang Z. q. Yao J. Hu q.l. Deng School of Mechanical Engineering Shanghai Jiao Tong UniversityShanghai 200030 China

laser shock forming （ISF） was a new technique realized by applying an impulsive pressure generated by laser-induced shock wave on the surface of metal sheet. lSF of metal sheet was investigated with experiments and numerical simulation. The basic theories were introduced; the surface quality and deformation of the processed titanium sample （TA2） were examined; ABAqUS was used to simulate ISF and the central displacement of the shocked region was measured and compared with the simulation. Overlapped ISF treatment was experimentally carried out to produce groove and simulation. The results showed that the surface quality and the microstructure with single laser pulse had no remarkable change, and ablation was observed on the surface of the sample with overlapped pulses. The deformation observed in the numerical simulation agreeed with that observed in the experimental measurement quite well.

关键词： laser shock forming numerical simulation surface quality deformation

SCAlING PROPERTIES OF INTERFACES IN CRYSTAlS UNDER NONEqUIlIBRIUM CONDITIONS

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Acta Metallurgica Sinica(English letters) 1997年第5期10卷 415-418页

作者： Shi, D.W. huang, J.Y. long, q.W. Inst of Metal Research Chinese Acad of Sciences Shenyang China

An equation of langevin type was proposed to describe the interface evolution in crystals under nonequilibrium conditions (such as in Cu-Fe or Cu-Co system upon ball milling). The scaling properties (H) of this equation is in good agreement with the Monte Carlo simulations described by Bellon and Averback. In this equation the volume diffusion and interface diffusion are all important and this is consistent with some experimental results.

关键词： Ball milling Binary alloys Crystals Mathematical models Nanostructured materials Surface roughness

The relationship between dolomite textures and their formation temperature: a case study from the Permian-Triassic of the Sichuan Basin and the lower Paleozoic of the Tarim Basin

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Petroleum Science 2014年第1期11卷 39-51页

作者： huang Sijing huang Keke lü Jie lan Yefang State Key laboratory of Oil and Gas Reservoir Geology and Exploitation Chengdu University of Technology Institute of Sedimentary Geology Chengdu University of Technology College of Earth Sciences Chengdu University of Technology

Study of dolomite texture can contribute to understanding the process of *** research reports textures and homogenization temperatures of dolomites from the Permian-Triassic strata in the Sichuan Basin and the lower Paleozoic strata in the Tarim Basin,which provided insights into relationships between dolomite textures and their formation *** results are summarized as follows：1） dolomites with well-preserved texture indicate low dolomitization ***,in certain diagenetic environments,the hydrothermal dolomitization may completely or partially preserve the original texture of dolomites.2） The formation temperatures of non-planar dolomites are always higher than those of planar dolomites.3） The formation temperatures of dolomite cements are generally higher than those of replacive dolomites.4） Although the formation temperatures of saddle dolomite cements have a wide range,they show higher values than those of the planar subhedral to euhedral dolomite ***,saddle dolomites could generally be an indicator of high precipitation temperature.5） The fluid Mg/Ca ratio is another element controlling dolomite *** dolomites,which precipitate from hypersaline fluids with a high Mg/Ca ratio in a subaerial environment could also have features of non-planar anhedral crystal shape because of rapid nucleation and crystallization during dolomitization.

关键词： The Permian-Triassic of the Sichuan Basin the lower Paleozoic of the Tarim Basin dolomite textures formation temperature of dolomites

Synthesis of CMC-Multipeptide Conjugate

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Chinese Chemical letters 1998年第1期9卷 23-24页

作者： Wang, DX huang, l Chinese Acad Med Sci Inst Mat Med Beijing 100050 Peoples R China Peking Union Med Coll Beijing 100050 Peoples R China

The synthesis of carboxymethyl cellulose (CMC)-multipeptide conjugate is reported in the present paper. This new type of peptide-polymer surrogate possesses some merits, such as ease of synthesis, high density of pept... 详细信息

关键词： peptide carboxymethyl cellulose conjugate polymer ligation

Oxygen and Nitrogen Effects on MC Carbide in K465 Nickel-Base Superalloy

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稀有金属材料与工程 2009年第A03期38卷 13-16页

作者： Wang l N Zheng q Sun X F Guan H R Hu Z q Institute of Metals Research Chinese Academy of Sciences Shenyang 110015 China

Effects of oxygen and nitrogen on MC carbide in nickel-base superalloy K465 were investigated, because neither of the two gas elements was found to decide MC carbide morphology monotonically. The morphology of MC carbide under alloy solidified in conventional investment casting condition was observed to transform from script-type to block-type with the total oxygen and nitrogen content (gas content) in samples rising up from 1.2×10-6 mol/g to 2.6×10-6 mol/g. The area fraction and composition of the MC carbide also varied with increase of gas content. However, the morphology of MC carbide kept to be script-type even when gas content was up to 3.4×10-6 mol/g in samples solidified with a much higher cooling rate. These results indicate that effects of gas content on formation of MC carbide can be observed in specimens solidified with low cooling rate, but such changes in MC carbide cannot be found when the cooling rate is high.

关键词：氧碳化物氮含量物理性能碳化物