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Nonlinear flutter analysis of stiffened composite panels in super-sonic flow

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science china(Physics,Mechanics & Astronomy) 2010年第2期53卷 336-344页

作者： YUAN Kaihua & QIU ZhiPing school of aeronautic science and Engineering,beijing university of aeronautics and astronautics,beijing 100191,china beijing university of aeronautics and astronautics School of Aeronautic Science and Engineering Beijing China (GRID:grid.64939.31) (ISNI:***)

The flutter instability of stiffened composite panels subjected to aerodynamic forces in the supersonic flow is investigated. based on hamilton's principle,the aeroelastic model of the composite panel is established by using the von Karman large deflection plate theory,piston theory aerodynamics and the quasi-steady thermal stress theory. Then,using the finite element method along with bogner-Fox-schmit elements and three-dimensional beam elements,the nonlinear equations of motion are derived. The effect of stiffening scheme on the flutter critical dynamic pressure is demonstrated through the numerical example,and the nonlinear flutter characteristics of stiffened composite panels are also analyzed in the time domain. This will lay the foundation for design of panel structures employed in aerospace vehicles.

关键词： panel flutter piston theory finite element method quasi-steady thermal stress critical dynamic pressure stiffened composite panel

The Numerical simulation on cooling Effect of Micro-capsulated Phase change material suspension in Laminar Thermal Developing section

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The Numerical Simulation on Cooling Effect of Micro-capsulat...

The Fifth International conference on Fluid Mechanics

作者： P.Q.liu j.jin~* G.P.lin school of aeronautic science and technology beijing university of aeronautics and astronautics beijing 100083 china

＜正＞The microcapsulated phase change material（MEPcM） suspension has obtained more and more *** present,the numerical models concerning MEcPM suspension are generally reduced to single-phase *** this paper,a novel two-phase model is *** use of this numerical model,the cooling effect of MEPcM suspension under different velocities,heat fluxes and concentrations is *** results are at variance with experimental results *** is discovered that the cooling effect of high concentration MEPcM suspension at low heat flux is best, but will go down quickly as the heat flux increasing *** cooling effect of low concentration is better than that of water in the entire range of heat flux.

关键词： microcapsulated phase change material(MEPcM) two-phase model effective thermal conductivities heat consistence

synthesis and characterization of acrylic modified epoxy prepolymers for UV-curable adhesives

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Synthesis and characterization of acrylic modified epoxy pre...

第十一届国际材联亚洲材料大会

作者： chEN Yichi~a,zhang hongmei~a,ZhU liqun~b,hETao~a,li weiping~b,and liU huicong~b a school of chemistry & Environment,beijing university of aeronautics and astronautics,beijing 100191,china b school of material science & Engineering,beijing university of aeronautics and astronautics,beijing 100191,china

Five kinds of epoxy acrylate reactive prepolymers with different molecular weight(Mw)were synthesized and used to formulate the UV-curable adhesives by the addition of photo-initiator,reactive diluent,crosslinker and other additives as *** structural characterization of the prepolymers was made by FT-IR and h-NMR spectra respectively,while the structural changement before and after UV-curing was characterized by *** of the said prepolymers were measured by gel permeation chromatography(GPc).Tensile shear adhesive strength of all the adhesives at different temperature were ***,an organo silane was incorporated in a comparative UV-curable adhesive sample to examine the effect of it on thermal stability and corrosion resistance of the adhesive.

关键词： UV-curing epoxy acrylate prepolymer adhesive shear adhesion strength molecular weight distribution

Effects of Nb on the high Temperature Mechanical Properties of TiNiAl Alloys

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Effects of Nb on the High Temperature Mechanical Properties ...

International conference on Aerospace materials(IcAM 2006)

作者： G.s.Qiu, x.Q.Zhao, L.j.Meng and h.b.xu school of materials science and Engineering, beijing university of aeronautics and astronautics, beijing 100083, china

A series of NiTiAl based alloys with different amount of Nb addition were prepared and the effects of Nb on both the mechanical properties and microstructure evolution were investigated. The addition of Nb can remarkably enhance the high temperature yield strength of these alloys. The highest yield strength of the alloys with 10 at% Nb reaches 1237MPa at 873K and 875MPa at 973K, respectively. The Ti2Ni(Al,Nb) precipitates and the solution strengthening effect might be responsible for the high yield stress achieved at high temperature.

关键词： TiNiAl, Nb, Intermetallics, high temperature

Effects of long-term aging at 1070℃on microstructure of Ni3Al-base single-crystal alloy Ic6sx

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Effects of long-term aging at 1070℃on microstructure of Ni3...

第十一届国际材联亚洲材料大会

作者： li Ming~a,sONG jinxia~a,li shusuo~b,and hAN Yafang~a a National Key Laboratory of Advanced high Temperature structural materials,beijing Institute of aeronautical materials(bIAM),beijing 100095,china b school of materials science and Engineering,beijing university of aeronautics & astronautics,beijing 100191,china

The effects of long-term aging at 1070℃for periods of 100 h to 1500 h on microstructure of Ni

关键词： oxides Ic6sx Ni3Al long-term aging microstructure

controlling secondary flow in high-lift low-pressure turbine using boundary-layer slot suction

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chinese journal of aeronautics 2024年第3期37卷 21-33页

作者： xiao QU liunan li Yingjie zhang xingen LU junqiang ZhU Yanfeng zhang school of Mechanical Engineering Beijing Institute of TechnologyBeijing 100081China Key Laboratory of light-Duty Gas-Turbine Institute of Engineering ThermophysicsChinese Academy of SciencesBeijing 100190China school of aeronautics and astronautics University of Chinese Academy of SciencesBeijing 100190China

The design of high-lift Low-Pressure Turbines(LPTs)causes the separation of the boundary layer on the suction side of the blade and leads to a strong secondary *** present study aims to minimize secondary losses through endwall slot suction and incoming wakes in a front-loaded high-lift LPT cascade with Zweifel of 1.58 under low Reynolds number of *** slotted schemes for the boundary layer of the endwall were designed(Plan A and Plan b),and the effects of suction mass flow on secondary flow were *** underlying physics of the endwall boundary layer of the suction and secondary flow under unsteady wakes was *** results show that slot suction at the endwall boundary layer can significantly suppress the secondary flow by removing low-momentum *** A and b significantly reduced the secondary kinetic energy by 44.2%and 36.9%,respectively,compared with the baseline cascade at the suction mass flow ratios of 1%.with an increase in the mass flow ratio of suction,the secondary flow was gradually reduced in both Plans A and *** is more beneficial to control the secondary flow to destroy the intersection of the pressure side and suction side of the horseshoe vortex before it develops into a passage *** unsteady wakes,the combined effects of incoming wakes and endwall boundary layer suction can further suppress the secondary flow at the suction mass flow ratios of 2%for Plan A,because the positive and negative vorticity inside upstream wakes accelerated the mixing of the main flow and secondary flow and thus increased the energy of secondary vortices.

关键词： Low-pressure turbine secondary flow Flow control boundary-layer suction Incoming wake

The soft x-ray Imager(sxI)on the sMILE Mission

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Earth and Planetary Physics 2024年第1期8卷 5-14页

作者： s.sembay A.L.Alme D.Agnolon T.Arnold A.beardmore A.belén balado margeli c.bicknell c.bouldin G.branduardi-Raymont T.crawford j.P.breuer T.buggey G.butcher R.canchal j.A.carter A.cheney Y.collado-Vega h.connor T.crawford N.Eaton c.Feldman c.Forsyth T.Frantzen G.Galgóczi j.Garcia G.Y.Genov c.Gordillo h-P.Gröbelbauer M.Guedel Y.Guo M.hailey D.hall R.hampson j.hasiba O.hetherington A.holland s-Y.hsieh M.w.j.hubbard h.jeszenszky M.jones T.Kennedy K.Koch-Mehrin s.Kögl s.Krucker K.D.Kuntz c.Lakin G.Laky O.Lylund A.martindale j.Miguel mas hesse R.Nakamura K.Oksavik N.Østgaard h.Ottacher R.Ottensamer c.Pagani s.Parsons P.Patel j.Pearson G.Peikert F.s.Porter T.Pouliantis b.h.Qureshi w.Raab G.Randal A.M.Read N.M.M.Roque M.E.Rostad c.Runciman s.sachdev A.samsonov M.soman D.sibeck s.smit j.søndergaard R.speight s.stavland M.steller TianRan sun j.Thornhill w.Thomas K.Ullaland b.walsh D.walton c.wang s.Yang school of Physics and Astronomy University of LeicesterLeicesterLE17RHUK space Park Leicester University of LeicesterLeicesterLE17RHUK Mullard space science Laboratory University College LondonDorkingRH56NTUK centre for Electronic Imaging Open UniversityMilton KeynesMK76 AAUK birkeland centre for space science Department of Physics and TechnologyUniv.of BergenN-5007 BergenNorway university of Vienna A-1010 ViennaAustria space Research Institute Austrian Academy of SciencesA-8042 GrazAustria National Institute of Aerospace technology MadridSpain EsTEc European Space Agency2201 AZ NoordwijkNetherlands state Key Laboratory of space weather National Space Science CentreBeijing 100190China university of Applied sciences and Arts Northwestern switzerland CH-5210 WindischSwitzerland Koegl space Gmbh CH-8157 DielsdorfSwitzerland space Acoustics Gmbh CH-8157 DielsdorfSwitzerland Zurich university of Applied sciences 8400 WinterhurSwitzerland Genov solutions N-5172 LoddefjordNorway sTM Engineering N-5165 LaksevagNorway john hopkins university Applied Physics Laboratory MD 20723USA NAsA/Goddard space Flight centre MD 20771USA center for space Physics Boston UniversityBostonMA 02215USA Department of Theoretical Physics and Astrophysics Masaryk University60177 BrnoCzech Republic Institute of Physics E¨otvo¨s Lor´and University1053 BudapestHungary Aerospace Information Research Institute Chinese Academy of SciencesBeijing 100045China centro de Astrobiologia(cAb) CSIC-INTAMadridSpain

The soft x-ray Imager(sxI)is part of the scientific payload of the solar wind magnetosphere Ionosphere link Explorer(sMILE)*** is a joint science mission between the European space Agency(EsA)and the chinese Academy of sciences(cAs)and is due for launch in *** is a compact x-ray telescope with a wide field-of-view(FOV)capable of encompassing large portions of Earth’s magnetosphere from the vantage point of the sMILE *** is sensitive to the soft x-rays produced by the solar wind charge exchange(swcx)process produced when heavy ions of solar wind origin interact with neutral particles in Earth’s *** provides a mechanism for boundary detection within the magnetosphere,such as the position of Earth’s magnetopause,because the solar wind heavy ions have a very low density in regions of closed magnetic field *** sensitivity of the sxI is such that it can potentially track movements of the magnetopause on timescales of a few minutes and the orbit of sMILE will enable such movements to be tracked for segments lasting many *** is led by the university of Leicester in the United Kingdom(UK)with collaborating organisations on hardware,software and science support within the UK,Europe,china and the United states.

关键词： soft x-ray Imaging micropore optics large area ccD

A ThEORY AND METhOD ON MODERN INTEGRATED DEsIGN PROcEss FOR AIRcRAFT DEsIGN

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A THEORY AND METHOD ON MODERN INTEGRATED DESIGN PROCESS FOR ...

The Eighth world conference on Integrated Design & Process technology

作者： j. xie1 b. song1 D. liu2 T. su3 1 school of aeronautics Northwestern Polytechnical university xi’an shaanxi P.R. china Department of Economics and management 2 North university of china Taiyuan shanxi P.R. china Department of 3 Vehicle and Power Engineering North university of china shanxi P.R. china

Aircraft design is a complex system engineering involved in multidisciplinary interactions and multi-technology fields. At present, with the development of aerospace industry and the changing designid

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crack patterns corresponding to the residual strength plateau of ceramics subjected to thermal shock

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Acta Mechanica sinica 2012年第3期28卷 670-674页

作者： h.-L.hou x.-E wu P.Yan F.song j.li c.-P.jiang school of aeronautic science and Engineering B eihang University100191 BeijingChina state Key Laboratory of Nonlinear Mechanics(LNM) Institute of MechanicsChinese Academy of Sciences100190 BeijingChina LsPM CNRS UPR 3407Universite Paris XIII99 Avenue Jean-Baptiste Clement93430 VilletaneuseFrance

The formation strength plateau of ceramics is addressed. A set of of 99A1203 are conducted, mechanism of the residual subjected to thermal shock thermal shock experiments where the thin specimens of 1 mm× 10 mm×50 mm exhibit parallel through edge cracks, and thus permit quantitative measurements of the crack patterns. The cracks evolve with the severity of ther- mal shock. It is found that there is a correlation between the length and density of the thermal shock cracks. The increase of crack length weakens the residual strength, whereas the increase of crack density improves it. In a considerably wide temperature range, the two contrary effects just counteract each other; consequently a plateau appears in the variation curve of the residual strength. A comparison between the numerical and experimental results of the residual strength is made, and they are found in good agreement. This work is helpful to a deep understanding of the thermal shock failure of ceramics.

关键词： ceramics Thermal shock crack patterns Residual strength - stress intensity factor