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Basic solution of two parallel Mode-I cracks in functionally graded materials

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Science China(Technological Sciences) 2008年第9期51卷 1380-1393页

作者： LIANG Jun Center for Composite Materials and Structures, harbin Institute of Technology, harbin 150080, China Center for Composite Materials and Structures Harbin Institute of Technology Harbin China

The solution of two parallel cracks in functionally graded materials subjected to a tensile stress loading is derived in this paper. To make the analysis tractable, it is assumed that the shear modulus varies exponentially with coordinate parallel to the crack. The problem is formulated through Fourier transform into four pairs of dual integral equations, in which the unknown variables are jumps of displace-ments across crack surfaces. To solve the dual integral equations, the jumps of displacements across crack surfaces are directly expanded as a series of Jacobi polynomials to obtain the shielding effects of the two parallel cracks in functionally graded materials.

关键词： parallel cracks shielding effects functionally graded materials

Finite time L_1 Approach for Missile Overload Requirement Analysis in Terminal Guidance

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Chinese Journal of Aeronautics 2009年第4期22卷 413-418页

作者： Ji Denggao,He Fenghua,Yao Yu Control and Simulation Center,harbin Institute of Technology,harbin 150080,China Control and Simulation Center Harbin Institute of Technology Harbin 150080 China

This article analyzes the problem about the missile overload requirement in a homing terminal guidance under various engagement scenarios. An augmented proportional navigation guidance （APNG） model is introduced on the basis of linear kinematics. To analyze the peak-to-peak performance of the terminal guidance system, a new finite time L1 performance measure for a linear time-varying （LTV） continuous system is proposed. Then, according to the idea of the adjoint system, a novel method for computing the L1 norm of a linear continuous system is first derived. Within the finite time L1 framework, the quantitative relation between the guidance loop dynamics and the maximum missile-target maneuver ratio is offered. This relation is expressed in the form of graphs and formulas that can be used to synthesize some of the major subsystem specifications for the missile guidance system. The illustrative examples show that a significant performance improvement is achieved with the proposed guidance loop dynamics.

关键词： finite time Lx-induced norm performance time varying systems missile overload requirement terminal guidance

Experimental study on a transpiration cooling thermal protection system

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Science China(Technological Sciences) 2010年第10期53卷 2765-2771页

作者： LIU Shuang & ZHANG BoMing Center for Composite Materials and Structure, harbin Institute of Technology, harbin 150080, China Center for Composite Materials and Structure Harbin Institute of Technology Harbin China

Transpiration cooling thermal protection systems (TPS) are investigated for potential applications in hypersonic and re-entry vehicles,which are subjected to the severe aerodynamic heating environment. In this paper a transpiration cooling thermal protection system was designed and manufactured,and an experiment platform with radiant heating at the bottom as heat source was developed. The cooling capacity of the transpiration cooling TPS was experimentally investigated. By combining transpiration cooling method with traditional TPS,the heat load capability of the TPS can be improved. The structure temperature with active cooling applied was much lower than that without active cooling applied under the same heat load as well as the heat load increased with active cooling than the one without active cooling for the same structure temperature. The experimental results showed that at 5800 s,the temperature of inner structure was 100°C with active cooling applied compared to 500°C without active cooling applied,then the temperature increased and reached to 360°C at 8300 s. Heat load of this transpiration cooling TPS can be increased by over 70% as compared to the passion one and the cooling capability of the transpiration TPS was about 1700 kJ/kg. The results can provide fundamental data for developing the transpiration cooling TPS.

关键词： thermal protection metallic thermal protection system active cooling transpiration cooling cooling capacity

Study on Rare Earth Co-Permeation and Conductivity of Complex K_7[BNi(OH_2)W_(11)O_(39)]·11H_2O

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Journal of Rare Earths 2005年第S1期23卷 239-242页

作者：刘永周百斌徐学勤Department of Chemistry harbin Normal Uniersity harbin 150080 China 韦永德所艳华 Department of Chemistry Harbin Normal Uniersity Harbin 150080 China Department of Chemistry Harbin Normal Uniersity Harbin 150080 China Department of Applied Chemistry Harbin Institute of Technology Harbin 150001 China Department of Applied Chemistry Harbin Institute of Technology Harbin 150001 China

The title compound was synthesized by means of direction. Its composition was determined by TG and ICP. The studies of IR and XRD indicate that the compound has the Keggin structure. The rare earth chemical thermal diffusion of the complex also was studied. The results show that the rare earth element Gd can permeate into the surface, interface and the body cavity of the prepared material. The results of TG-DTA show that the stable temperature is improved and the conductivity of the permeated sample is 3.05 S·cm -1, which is 4.67×106 times higher than that of the parent K_7[BNi(OH_2)W_ 11O_ 39]·11H_2O.

关键词： heteropoly complex rare earth co-permeation keggin structure conductivity

Three-dimensional Cure Simulation of Stiffened Thermosetting Composite Panels

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Journal of Materials Science & Technology 2010年第5期26卷 467-471页

作者： Guangquan Yue,Boming Zhang ,Fuhong Dai and Shanyi Du Center for Composite Materials,harbin Institute of Technology,harbin 150080,China Center for Composite Materials Harbin Institute of Technology Harbin 150080 China

Stiffened thermosetting composite panels were fabricated with co-curing *** the co-curing processing,the temperature distribution in the composite panels was *** investigation into the threedimensional cure simulation of T-shape stiffened thermosetting composite panels was *** tools and locating tools were considered in the cure *** distribution in the composites was predicted as a function of the autoclave temperature history.A nonlinear transient heat transfer finite element model was developed to simulate the curing process of stiffened thermosetting composite *** a simulation example was presented to demonstrate the use of the present finite element procedure for analyzing composite curing *** glass/polyester structure was investigated to provide insight into the nonuniform cure process and the effect of flexible tools and locating tools on temperature *** gradient in the intersection between the skin and the flange was shown to be strongly dependent on the structure of the flexible tools and the thickness of the skin.

关键词： Thermosetting composite Stiffened panels Co-curing Numerical simulation

TENSILE FRACURE IN AN Al-Li ALLOY 8090

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中国有色金属学会会刊：英文版 1995年第2期5卷 106-108页

作者： Jiang, Daming Wang,Yinong Hong, Bande Lei, Tingquan(harbin Institute of Technology, harbin 150080)Sun Fenglian(harbin University of Science and Technology, harbin 150001) harbin Inst of Technology Harbin China

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关键词： Al-Li alloy tensile fracture dimple rupture cleavage

An improved nonlinear control strategy for deep space formation flying spacecraft

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Acta Mechanica Sinica 2009年第6期25卷 847-856页

作者： Peng Li Pingyuan Cui Hutao Cui Deep Space Exploration Research Center,harbin Institute of Technology, 150080 harbin, China Deep Space Exploration Research Center Harbin Institute of Technology Harbin China

This paper aims to provide further study on the nonlinear modeling and controller design of formation flying spacecraft in deep space missions. First, in the Sun-Earth system, the nonlinear formation dynamics for the circular restricted three-body problem （CRTBP） and elliptic restricted three-body problem （ERTBP） are presented. Then, with the Floquet mode method, an impulsive controller is developed to keep the Chief on the desired Halo orbit. Finally, a nonlinear adaptive control scheme based on Nonzero set- point LQR and neural network is proposed to achieve high precision formation maneuver and keeping. The simulation results indicate that the proposed nonlinear control strategy is reasonable as it considers not only the orbit keeping of the Chief, but also the formation modeling inaccuracy. Moreover, the nonlinear adaptive control scheme is effective to improve the control accuracy of the formation keeping.

关键词： Spacecraft formation flying. Libration pointHalo orbit - Nonlinear control

Stiffness requirement of flexible skin for variable trailing-edge camber wing

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Science China(Technological Sciences) 2010年第4期53卷 1077-1081页

作者： YIN WeiLong Center for Composite Materials and Structures and Postdoctoral Station of Mechanics,harbin Institute of Technology,harbin 150080,China Center for Composite Materials and Structures and Postdoctoral Station of Mechanics Harbin Institute of Technology Harbin China

The method for analyzing the deformation of flexible skin under the air loads was developed based on the panel method and finite element *** deformation of flexible skin under air pressures and effects of the local deformation on the aerodynamic characteristics were *** results show that the flexible skin on the upper surface of trailing-edge will bubble under the air loads and the bubble has a powerful effect on the aerodynamic pressure near the surface of local *** the stiffness requirements for flexible skin of variable trailing-edge were given by using the Jacobs rule,i.e.,the maximum displacement of skin is not greater than 0.1% of wing *** show that the in-plane stiffness can be reduced by increasing the ratio of bending stiffness to in-plane *** the deformation of flexible skin increases with the in-plane stiffness decreasing,it depends on the bending *** the bending stiffness exceeds critical value,the deformation of flexible skin only depends on the bending stiffness and has nothing to do with the in-plane *** conclusions can be used for the structural design of flexible skin.

关键词： morphing aircraft variable trailing-edge flexible skin deformation stiffness requirement

MATHEMATICAL MODEL OF MILLING TEMPERATURE AND TEMPERATURE FIELD ANALYSIS FOR THREE-DIMEN-SIONAL COMPLEX GROOVE MILLING INSERT

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Chinese Journal of Mechanical Engineering 2003年第4期16卷 340-343页

作者： Li ZhenjiaDong LihuaTan GuangyuGuo QiangCheng YaonanCollege of Mechanical Engineering,harbin University of Scienceand Technology,harbin 150080, China College of Mechanical Engineering Harbin University of Science and Technology Harbin 150080 China

The mathematical model on the temperature of the waved-edge is constructedaccording to Jaeger's theory of moving solid and based on the used temperature model of the flatinsert. It is possible to forecast the milling temperature through programming. The comparableexperiments have been done between the two new three-dimension groove inserts (waved-edge insert,great edge insert) and flat fake insert. The theoretic forecast is in good agreement with theexperimental result. According to the cutting conditions, the boundary condition of finite elementanalysis on cutting temperature field is established, and the three-dimensional temperature fieldsof inserts with grooves are analyzed by FEM, so as to offer a reference basis for the design andoptimization of insert grooves.

关键词： Three-dimensional groove milling insert Cutting temperature mathematicalmodel Temperature field Finite element analysis