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In this paper we prove that the homogeneous spaceG/K has a structure of a globally symmetric space for every choice ofG andK, especially forG being compact.


Similarly, by a specific choice of the parameter, the level (1,0) vertex representation of the quantum totoidal algebra gives rise to a structure on irreducible level1 highest weightmodules.


A structure iterated by the unbalanced Feistel networks is introduced.


Acousticstructure sensitivity is used to predict the change of acoustic pressure when a structure design variable is changed.


However, the appearance of imaginary frequency phonon modes indicates the instability of such a structure.

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 Improved computational methods for dynamical analysis of various structures are now available and many universal computer programs have been developed. Accurate results of calculation depend great to a extent on the selection of physical parameters of a structure and the determination of the exciting force. This paper presents a calculational method in which characteristic parameters to be measured in experiments can be conveniently transformed into physical parameters. The calculation formulas are derived... Improved computational methods for dynamical analysis of various structures are now available and many universal computer programs have been developed. Accurate results of calculation depend great to a extent on the selection of physical parameters of a structure and the determination of the exciting force. This paper presents a calculational method in which characteristic parameters to be measured in experiments can be conveniently transformed into physical parameters. The calculation formulas are derived and the method of the identification of parameters discussed.  对各种结构的动力分析的计算方法已趋完善,并有大型通用程序可使用.振动分析的结果取决于结构参数的选择和激振力的确定.本文介绍由试验的特征参数转换到物理参数的一种计算方法,导出了计算公式,讨论了识别参数的方差.  It is well known that the classical bound theorems provide estimates of lower and upper bounds on the plastic limit loading of a structure. These are the basis of limit analysis which is a branch of applied plasticity in solid mechanics.In 1963, we suggested a generalized variational principle to compute appreximate plastic limit load[1,2]. Both the stress state σij and the velocity field are introduced and vary independently in the functional of the variational principle which is equivalent mathematically... It is well known that the classical bound theorems provide estimates of lower and upper bounds on the plastic limit loading of a structure. These are the basis of limit analysis which is a branch of applied plasticity in solid mechanics.In 1963, we suggested a generalized variational principle to compute appreximate plastic limit load[1,2]. Both the stress state σij and the velocity field are introduced and vary independently in the functional of the variational principle which is equivalent mathematically to the whole set of equations in limit analysis.A further development of this variational principle is given in this paper in order to establish new bound theorems which will give better estimates than that of the classical theorems.Let the multiplier load factor be defined by eq. (2.6) in the text where Pbasic loading such that vP is the actual loading, σijstress state, f(σij)quadratic yielding function, H(x)Heaviside function, and aweighting factor which may take nonunique forms as or others.Based on expression (2.6) in the text, new bound theorems are formulated as following:Theorem of lower bound: Given a stress state an, satisfying the equilibrium requirements with the load P, for arbitrary variation of the independent but kinematically admissible velocity field wi, the minimum value vmin of the expression (2.6) will be smaller than the actual multiplier load factor for the plastic limit state of the structure.Theorem of the upper bound: Given a velocity field wi, satisfying thekinematic requirements with the boundary conditions, for arbitrary variation of the independent statically admissible stress state σij, the maximum value vmax of the expression (2.6) will be larger than the actual multiplier load factor for the plastic limit state of the structure.Computer algorithm can be formulated to determine the lower limit as well as the upper limit of the. plastic loading. Furthermore, by using alternatively the lower bound theorem and the upper bound theorem, the exact solution should be approached through an iteration process.  本文在文[1]的极限分析一般变分式的基础上,进行了发展,导出了极限乘子的新的上、下限定理。由本文上、下限定理决定的极限乘子的上、下限将比经典的上、下限定理给出的更为靠近准确解。然后又对于两种权因子得到的上、下限进行了比较。最后,在新的上、下限定理的基础上,建议了一套推求极限乘子的计算机算法。  The influence of node flexibility on the brace buckling load of an offshore oil production jacket is investigated. A simplified inplane buckling analysis method for individual brace members is presented. The buckling analysis method has been adopted by WS Atkins & partners in the U.K.The basic equation for the analysis of the brace buckling load can be derived by considering a simple beam in Fig.2. The beam is subjected to an axial compresive force P, couples Ma and Mb, The angles θa and θb giving the rotation... The influence of node flexibility on the brace buckling load of an offshore oil production jacket is investigated. A simplified inplane buckling analysis method for individual brace members is presented. The buckling analysis method has been adopted by WS Atkins & partners in the U.K.The basic equation for the analysis of the brace buckling load can be derived by considering a simple beam in Fig.2. The beam is subjected to an axial compresive force P, couples Ma and Mb, The angles θa and θb giving the rotation of the ends of the beam in Fig.2 are obtained from equations(1) and (2) ,and notations(3)~(6). Using the notations (7)~(9), we can obtain equation (18) which is a basic equation considering the influence of node flexibility on the brace buckling load. It defines a relationship between A. and B for any value of P/Pcr. The relationship listed in Table 1 can be expressed by graphs 3 and 4, α and β can be obtained by a structure analysis program of jacket considering the influence of node flexibility. The effect of joint flexibility on the inplane buckling load of the brace can be determined by these graphs. In example 2, we obtain the influence of node flexibility on the brace buckling load that by a change of the chord wall from 67 mm to 37.5mm the buckling load is dropped by about 12.6%.  海洋平台的导管架的管结点具有一定的柔性,其柔性大小对杆件的屈曲有影响,这种影响是复杂的。本文提出一种工程计算方法,导出基本方程;给出工程计算图表,可以简明地计算管结点柔性对杆件屈曲的影响。   << 更多相关文摘 
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