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A method of constructing a database-free optimal dynamical system and a global optimal dynamical system

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Science china(Physics,Mechanics & Astronomy) 2008年第7期51卷 905-915页

作者： wu chuijie1? & wang liang2 1 state key laboratory of structural analysis for industrial equipment, dalian university of technology, dalian 116024, china 2 Research Center for Fluid Dynamics, School of Science, PLA university of Science and technology, Nanjing 211101, china state key laboratory of structural analysis for industrial equipment Dalian University of Technology Dalian China Research Center for Fluid Dynamics School of Science PLA University of Science and Technology Nanjing China

In this paper, to overcome the drawbacks of POT which minimize the reminder, not only the optimal functional with minimal residual is put forward, but also the method of global optimization is used. Under the condition of large reminder, the optimal bases can also be obtained through the method of POTres without the approaching of initial conditions. In addition, compared with local optimization, the advantage of global optimization is remarkable. On the one hand, we can expect that the dynamical system based on the global optimal bases will include more information than the ones based on the local optimal bases, since the global optimal bases are much more precise than the local optimal bases. On the other hand, from the point of view of error, the global optimal bases are independent of the choice of the object functional and the initial bases.

关键词： dynamical system residual global optimization

Numerical simulations of self-propelled swimming of 3D bionic fish school

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中国科学:技术科学 2010年第3期 334-334页

Numerical simulations of self-propelled swimming of a three dimensional bionic fish and fish school in a viscous fluid are carried *** is done with the assistance of a parallel software package produced for 3D moving boundary *** computational fluid dynamics package combines the adaptive multi-grid finite volume method,the immersed boundary method and VOF (volume of fluid) *** using the package results of the self-propelled swimming of a 3D bionic fish and fish school in a viscous fluid are *** comparison to the existing experimental measurements of living fishes,the predicted structure of vortical wakes is in good agreement with the measurements.

关键词： adaptive multi-grid immersed boundary method self-propelled swimming fish school 3D bionic fish

An adaptive version of ghost-cell immersed boundary method for incompressible flows with complex stationary and moving boundaries

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Science china(Physics,Mechanics & Astronomy) 2010年第5期53卷 923-932页

作者： wang liang1 & wu chuijie2,3 1 School of Science,PLA university of Science and technology,Nanjing 211101,china 2 state key laboratory of structural analysis for industrial equipment,dalian university of technology,dalian 116024,china 3 School of Aeronautics and Astronautics,dalian university of technology,dalian 116024,china School of Science PLA University of Science and Technology Nanjing China state key laboratory of structural analysis for industrial equipment Dalian University of Technology Dalian China School of Aeronautics and Astronautics Dalian University of Technology Dalian China

An adaptive version of immersed boundary method for simulating flows with complex stationary and moving boundaries is *** method employs a ghost-cell methodology which allows for a sharp representation of the immersed *** simplify the implementation of the methodology,a volume-of-fluid method is introduced to identify the immersed *** addition,the domain is spatially discretized using a tree-based discretization which is relatively simple to implement a fully flexible adaptive refinement ***,the methodology is validated by comparing it with numerical and experimental results on three cases:(1) the flow passing a circular cylinder at Re=40 and Re=100,(2) a periodic oscillation of a circular cylinder in fluid at rest and(3) the self-propelled fish-like swimming at Re=6400.

关键词： adaptive mesh refinement ghost-cell immersed boundary method moving boundaries

The Micro/Nanostructure Characteristics and the Mechanical Properties of Hemifusus tuba Conch Shell

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Journal of Bionic Engineering 2010年第4期7卷 3+308-313页

作者： Yan liang~1,Jie Zhao~2,Chengwei wu~1 1.state key laboratory of structural analysis for industrial equipment,Department of Engineering Mechanics,dalian university of technology,dalian 116024,P.R.china 2.School of Materials Science and Engineering,dalian university of technology,dalian 116024,P.R.china state key laboratory of structural analysis for industrial equipment Department of Engineering Mechanics Dalian University of Technology Dalian P. R. China School of Materials Science and Engineering Dalian University of Technology Dalian P. R. China

The mollusk shell mobilizes calcium from environment for skeletal *** occurs through synthesizing solidsin solution in the presence of organic molecules of specific interior regions of the conch *** ultrastructure and microhardnessof the Hemifusus tuba conch shell living in the Huang/Bo sea area are investigated in the *** is shown that thecomposition and microstructure of the mollusk shell vary in different *** prodissoconch shell consists only of aragonitewith the crossed-lamellar *** the spiral shell and the body shell of the Hemifusus tuba conch shell arecomposed of one calcite layer and several aragonite *** calcite layer consists of cylindrical grains,but the aragonitelayers are crossed-lamellar ultrastructure at three size *** minimum structure size (the third-order lamella) is at about20 nm - 80 *** margin of shell aperture is only composed of calcite with cylindrical *** natural optimization of theshell microstructure is intimately due to the growth of the Organic *** different positions the microhardness of molluscshell is different due to different crystal structures and crystal *** growth process of shells allows a constantrenewal of the material,thus enabling their functional adaptation to external environments.

关键词： conch shell microstructure aragonite calcite crossed-lamellar

Large-eddy simulation of formation of three-dimensional aeolian sand ripples in a turbulent field

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Science china(Physics,Mechanics & Astronomy) 2008年第8期51卷 945-960页

作者： wu chuijie1,wang Ming2 & wang liang3 1 state key laboratory of structural analysis for industrial equipment,dalian university of technology,dalian 116024,china 2 Yellow River Institute of Hydraulic Research,Zhengzhou 450003,china 3 Research Center for Fluid Dynamics,Science School,PLA university of Science and technology,Nanjing 211101,china state key laboratory of structural analysis for industrial equipment Dalian University of Technology Dalian China Yellow River Institute of Hydraulic Research Zhengzhou China Research Center for Fluid Dynamics Science School PLA University of Science and Technology Nanjing China

With the method of large-eddy simulation,the equation of spherule motion and the method of immersed boundary condition,numerical simulations of three-dimen-sional turbulent aeolian motion and the formation of sand ripples under three-di-mensional turbulent wind and the mutual actions of saltation and creeping motion were carried out. The resulting sand ripples have the form that is flat on the upwind side and steep on the leeward,which is identical to the sand ripples in nature. We also realized the self-restoration process of three-dimensional sand ripples,which shows the correctness of the method of numerical simulation and the models of saltation and creeping. Finally,We analyzed the influence of sand ripples on the three-dimensional turbulent wind field,and found that due to the appearance and development of sand ripples,in the normal direction of ground there exists stronger energy exchange,and moreover,there is close correspondence between the forms of sand ripples and the vorticity close to the ground surface.

关键词： large-eddy simulation equation of spherule motion sand ripples saltation creep

Functions for patch test in finite element analysis of the Mindlin plate and the thin cylindrical shell

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Science china(Physics,Mechanics & Astronomy) 2009年第5期52卷 762-767页

作者： CHEN WanJi 1,2 ,wang JinZhi 1,3 &ZHAO Jie 1 1state key laboratory for structural analysis of industrial equipment,dalian university of technology,dalian 116023,china 2Institute for structural analysis of Aerocraft,Shenyang Institute of Aeronautical Engineering,Shenyang 110136,china 3 College of Science,Institute of dalian Nationalities,dalian 116022,china state key laboratory for structural analysis of industrial equipment Dalian University of Technology Dalian China Institute for structural analysis of Aerocraft Shenyang Institute of Aeronautical Engineering Shenyang China College of Science Institute of Dalian Nationalities Dalian China

Current patch test for Mindlin plate element only satisfies the zero shear deformation *** patch test of non-zero constant shear for Mindlin plate problem cannot be *** shell element, the patch test does not even *** on the theory of enhanced patch test proposed by Chen W J (2006),the authors proposed the enhanced patch test function for Mindlin plate and thin cylindrical shell *** enhanced patch test function can be used to assess the convergence of the Mindlin plate and cylindrical thin shell elements.

关键词： Mindlin plate thin cylindrical shell finite element enhanced patch test test function

Micron-Nanometer Aluminum Oxide Prepared by Detonation of Powder Mixed Explosive

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Micron-Nanometer Aluminum Oxide Prepared by Detonation of Po...

Size and Layout Optimizations of Stiffened Shells under Axial Compression

加速功能材料自主创新，促进西部战略性新兴产业发展——2...

作者： Ruiyong LI 1,Honghao YAN 2,Xiaohong wang 2,Xiaojie LI 2 1 College of Pipeline and Civil Engineering china university of Petroleum (East china),Qingdao,china 2 state key laboratory of structural analysis for industrial equipment dalian university of technology,dalian,china

The aluminum oxide is prepared by detonation of the powder mixture explosive made of aluminum nitrate and *** results of transmission electron microscope morphology analysis and x-ray diffraction analysis indicate that all granules of aluminum oxide are spherical,the size of major granules is more than 100 nm,the size of little granules is less than 100 nm,the average size is about 500 nm,and the aluminum oxide are α and γ phases.

关键词： aluminum nitrate RDX detonation micron-nanometer aluminum oxide

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Size and Layout Optimizations of Stiffened Shells under Axia...

The Seventh china-Japan-Korea Joint Symposium on Optimization of structural and Mechanical Systems

作者： Bo wang1 Peng Hao1 Gang Li1 Zhifeng Zhang2 Bin wang2 and Chunxiao Zhou2 1Dept.of Engineering Mechanics state key laboratory of structural analysis of industrial equipment dalian university of technology 116023 dalian china 2Beijing Institute of Astronautical Systems Engineering 100076 Beijing china

The extensive use of stiffened shells in aerospace industries is mainly motivated by the high stiffness-to-weight and strength-to-weight *** these thin-walled structures,buckling is one of the main failure *** methods and programs are available for the analysis of stiffened shells,ranging from simple closed form solutions to complicated discrete ***,many optimizations have been carried out for metallic and composite stiffened shells against *** variables involved in the optimizations are usually stiffener size,stiffener spacing,skin laminate sequence and angle,***,the layout optimizations of stiffened shells are rarely reported,which are capable of increasing the bending stiffness without the increase of structural ***,the buckling of stiffened shells can be categorized as elastic and plastic buckling patterns,and the failures mostly occur at the intermediate section of shell and the sections close to both ends *** is supposed to be efficient to adjust the location of stiffeners for the purpose of improving the local stiffness against buckling,moreover,without the increase of additional weight.

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射孔枪射流形成的数值模拟与弹壳设计

塑性工程学报 2010年第6期17卷 121-126页

作者：金玮玮张昭韩秀清张洪武大连理工大学工程力学系工业装备结构分析国家重点实验室长春工业大学基础科学学院

采用有限元方法模拟射孔枪射流的形成过程,并进一步模拟了射孔弹弹壳撞击射孔枪管壁的过程,对比不同情况下,在弹壳外壁上增加不同的附加金属层,对射孔枪管壁鼓包高度的影响。研究发现,增加一层软金属可以有效地减少鼓包的高度,并且软金... 详细信息

采用有限元方法模拟射孔枪射流的形成过程,并进一步模拟了射孔弹弹壳撞击射孔枪管壁的过程,对比不同情况下,在弹壳外壁上增加不同的附加金属层,对射孔枪管壁鼓包高度的影响。研究发现,增加一层软金属可以有效地减少鼓包的高度,并且软金属的屈服极限对其高度有较大的影响,屈服越大的材料,在相同的应变率下,吸收的能量相对较多,鼓包高度会相应越低,加7075铝合金的射孔弹壳撞击枪壁,较未加软金属的情况,可以减少52.1%的鼓包高度。在应变率相近的情况下,材料的屈服极限与鼓包的高度,存在近似的线性关系。

关键词：射孔枪有限元法射流