Please wait a minute...


当期目录

    2000年 第21卷 第4期    刊出日期:2000-04-18
    论文
    GENERAL SOLUTION FOR U-SHAPED BELLOWS OVERALL-BENDING PROBLEMS
    朱卫平;郭平;黄黔
    2000, 21(4):  371-382. 
    摘要 ( 478 )   PDF (628KB) ( 484 )  
    参考文献 | 相关文章 | 多维度评价
    The formulae for stresses and angular displacements of U-shaped bellows overall bending in a meridian plane under pure bending moments are presented based on the general solution for slender ring shells proposed by Zhu Weiping, et al. and the solution for ring plates. The results evaluated in this paper are compared with those on EJMA (standards of the expansion joint manufacturers association) and of the experiment given by Li Tingxin, et al.
    ON A NEW ALGORITHM OF CONSTRUCTING SOLITARY WAVE SOLUTIONS FOR SYSTEMS OF NONLINEAR EVOLU-TION EQUATIONS IN MATHEMATICAL PHYSICS
    闫振亚;张鸿庆
    2000, 21(4):  383-388. 
    摘要 ( 551 )   PDF (371KB) ( 357 )  
    参考文献 | 相关文章 | 多维度评价
    According to the improved sine-cosine method and Wu-elimination method, a new algorithm to construct solitary wave solutions for systems of nonlinear evolution equations is put forward. The algorithm has some conclusions which are better than what the hyperbolic function method known does and simpler in use. With the aid of MATHEMA- TICA, the algorithm can be carried out in computer.
    ABUNDANCE OF UNIMODAL MAPS WITH DENSE CRITICAL ORBIT AND PREFIXED CRITICAL ORBIT
    曹永罗;王兰宇
    2000, 21(4):  389-394. 
    摘要 ( 433 )   PDF (337KB) ( 388 )  
    参考文献 | 相关文章 | 多维度评价
    For the so-called quadratic family, it is proved that, there exists a positive Lebesgue measure set E in the parameter space such that the corresponding map has a dense critical orbit in the support set of the invariant measure for almost all parameters in E; it is also proved that there is a dense set in E such that the critical orbit of the corresponding map enter the reversed fixed point.
    FIfth-ORDER ISOTROPIC DESCARTES TENSOR
    阎大桂;徐军;严尚安;付诗禄
    2000, 21(4):  395-398. 
    摘要 ( 484 )   PDF (261KB) ( 470 )  
    参考文献 | 相关文章 | 多维度评价
    Fifth-order isotropic descartes tensor and its existence theorem and representation problems are researched, then a general representation formula of fifth-order isotropic descartes tensor is got.
    SINGULAR INTEGRAL EQUATIONS AND BOUNDARY ELEMENT METHOD OF CRACKS IN THERMALLY STRESSED PLANAR SOLIDS
    徐春晖;秦太验;华云龙
    2000, 21(4):  399-406. 
    摘要 ( 742 )   PDF (486KB) ( 586 )  
    参考文献 | 相关文章 | 多维度评价
    Using the method of the boundary integral equation, a set of singular integral equations of the heat transfer problems and the thermo-elastic problems of a crack embedded in a two-dimensional finite body is derived, and then its numerical method is proposed by the numerical method of the singular integral equations combined with boundary element method. Moreover, the singular nature of temperature gradient field near the crack front is proved by the main-part analysis method of the singular integral equation, and the singular temperature gradients are exactly obtained. Finally, several typical examples are calculated.
    CONSTRUCTION OF HIGH-ORDER ACCURACY IMPLICIT RESIDUAL SMOOTHING SCHEMES
    倪明玖;席光;王尚锦
    2000, 21(4):  407-414. 
    摘要 ( 492 )   PDF (537KB) ( 292 )  
    参考文献 | 相关文章 | 多维度评价
    Referring to the construction way of Lax-Wendroff scheme, new IRS(Implicit Residual Smoothing) schemes have been developed for hyperbolic, parabolic and hyper-parabolic equations. These IRS schemes have 2nd-order or 3rd-order time accuracy, and can extend the stability region of basic explicit time-stepping scheme greatly and thus can permit higher CFL number in the calculation of flow field. The central smoothing and upwind-bias smoothing techniques have been developed too. Based on one-dimensional linear model equation, it has been found that the scheme is unconditionally stable according to the von-Neumann analysis. The limitation of Dawes’ method, which has been applied in turbomachinery widespreadly, has been discussed on solving steady flow and viscous flow. It is shown that stable solution of this method is not completely independent with the value of time step. In the end, numerical results by using IRS schemes and Dawes’ method as well as TVD (total variation diminishing) scheme and four-stage Runge-Kutta technique are presented to verify the analytical conclusions.
    A CRYSTALLOGRAPHIC MODEL FOR THE ORIENTATION DEPENDENCE OF LOW CYCLIC FATIGUE PROPERTY OF A NICKEL-BASE SINGLE CRYSTAL SUPERALLOY
    岳珠峰;陶仙德;尹泽勇;李海燕
    2000, 21(4):  415-424. 
    摘要 ( 494 )   PDF (643KB) ( 448 )  
    参考文献 | 相关文章 | 多维度评价
    Fully reversed low cyclic fatigue (LCF) tests were conducted on [0 0 1], [0 1 2], [1 1 2], [0 1 1] and [1 1 4] oriented single crystals of nickel-based superalloy DD3 with different cyclic strain rates at 950℃. The cyclic strain rates were chosen as 1.0×10-2 , 1.33×10-3 and 0.33×10-3s-1. The octahedral slip systems were confirmed to be activated on all the specimens. The experimental result shows that the fatigue behavior depends on the crystallographic orientation and cyclic strain rate. Except [0 0 1] orientation specimens, it is found from the scanning electron microscopy (SEM) examination that there are typical fatigue striations on the fracture surfaces. These fatigue striations are made up of cracks. The width of the fatigue striations depends on the crystallographic orientation and varies with the total strain range. A simple linear relationship exists between the width and total shear strain range modified by an orientation and strain rate parameter. The nonconformity to the Schmid law of tensile/compressive flow stress and plastic behavior existed at 950℃, and an orientation and strain rate modified Lall-Chin-Pope (LCP) model was derived for the nonconformity. The influence of crystallographic orientation and cyclic strain rate on the LCF behavior can be predicted satisfactorily by the model. In terms of an orientation and strain rate modified total strain range, a model for fatigue life was proposed and used successfully to correlate the fatigue lives studied.
    GENERAL FAILURE PROBABILITY SIMULATION AND APPLICATION FOR MULTI-MODE
    吕震宙;岳珠峰;冯蕴雯
    2000, 21(4):  425-432. 
    摘要 ( 597 )   PDF (458KB) ( 506 )  
    参考文献 | 相关文章 | 多维度评价
    A general failure probability simulation and deviation evaluation methods were presented for fuzzy safety state and fuzzy failure state. And the corresponding number integral method was simultaneously established. As the distribution of state variable and the membership of the state variable to the fuzzy safety set were normal, the general failure probability of the single failure mode had precise analytic solution, which was used to verify the precision of the presented methods. The results show that the evaluation of the simulation method convergences to the analytic solution with the number increase of the sampling. The above methods for the single failure mode was extended to the multi-mode by the expansion and probability principles. The presented methods were applied to the engineering problem. For the number of significant mode is not too many, the high precision solution can be given by the presented number simulation and number integral methods, which is illustrated by the engineering examples. In addition, the application scope of the methods was discussed.
    ADJOINT SYSTEM INTEGRALS FOR OPTIMAL SPACE N-IMPULSE TRANSFER
    吴玉良
    2000, 21(4):  433-436. 
    摘要 ( 391 )   PDF (255KB) ( 297 )  
    参考文献 | 相关文章 | 多维度评价
    The adjoint system integrals for time free, optimal N-impulse transfer during a firing period in 5-phase selected are derived.
    4TH-ORDER SPLINE WAVELETS ON A BOUNDED INTERVAL
    段继伟;李启光
    2000, 21(4):  437-446. 
    摘要 ( 567 )   PDF (464KB) ( 392 )  
    参考文献 | 相关文章 | 多维度评价
    The 4th-order spline wavelets on a bounded interval are constructed by the 4th-order truncated B-spline functions. These wavelets consist of inner and boundary wavelets. They are bases of wavelet space with finite dimensions. Any function on an interval will be expanded as the sum of finite items of the scaling functions and wavelets. It plays an important role for numerical analysis of partial differential equations, signal processes, and other similar problems.
    PARAMETER IDENTIFICATION OF DYNAMIC MODELS USING A BAYES APPROACH
    李书;卓家寿;任青文
    2000, 21(4):  447-454. 
    摘要 ( 556 )   PDF (525KB) ( 337 )  
    参考文献 | 相关文章 | 多维度评价
    The Bayesian method of statistical analysis has been applied to the parameter identification problem. A method is presented to identify parameters of dynamic models with the Bayes estimators of measurement frequencies. This is based on the solution of an inverse generalized eigenvalue problem. The stochastic nature of test data is considered and a normal distribution is used for the measurement frequencies. An additional feature is that the engineer’s confidence in the measurement frequencies is quantified and incorporated into the identification procedure. A numerical example demonstrates the efficiency of the method.
    PERIODICITY AND STRICT OSCILLATION FOR GENERALIZED LYNESS EQUATIONS
    李先义;肖功福
    2000, 21(4):  455-460. 
    摘要 ( 505 )   PDF (314KB) ( 322 )  
    参考文献 | 相关文章 | 多维度评价
    A generalized Lyness equation is investigated as follows xn+1=xn/(a+bxn)xn-1, n=0,1,2,…,(*) where a,b∈[0,∞) with a+b>0 and where the initial values x-1,x0 are arbitrary positive numbers. Some new results, mainly a necessary and sufficient condition for the periodicity of the solutions of Eq.(*) and a sufficient condition for the strict oscillation of all solutions of Eq(*),are obtained. As an application, the results solve an open problem presented by G.Ladas.
    ANALYTICAL SOLUTION FOR MODE Ⅲ DYNAMIC RUPTURE OF STANDARD LINEAR VISCOELASTIC SOLID WITH NONLINEAR DAMPING
    范家参
    2000, 21(4):  461-470. 
    摘要 ( 481 )   PDF (594KB) ( 405 )  
    参考文献 | 相关文章 | 多维度评价
    Introducing the nonlinear Rayleigh damping into the governing equation of the Mode Ⅲ dynamic rupture for standard viscoelastic solid, this equation is a partial differential and integral equation. First, eliminating the integral term, a PDE of third-order is obtained. Then, applying the small parameter expansion method, linearized asymptotic governing equation for each order of the small parameter is obtained. Dividing the third-order PDE into an elastic part with known solution, the rest part pertains to viscous effect which is neither a Mathieu equation nor a Hill one. The WKBJ method is still adopted to solve it analytically.
    PASSIVE VIBRATION CONTROL OF SPACE STRUCTURE BY RECEPTANCE THEORY
    严天宏;郑钢铁;黄文虎
    2000, 21(4):  471-478. 
    摘要 ( 469 )   PDF (517KB) ( 495 )  
    参考文献 | 相关文章 | 多维度评价
    The vibration of three-dimensional frame structures was studied as receptance motion. A receptance model was constructed for passive vibration reduction. First, the universal receptance computational method suitable to any combination of boundary conditions was given, and then the way of passive damping-damping elements was analyzed, and an iterative approach to select optimal damping positions, whose dissipated power is larger than the others, was proposed based on the results of receptance analysis. The results show that, the receptance model is very suitable for local modification and analysis of structures.
    ROBUST STABILITY FOR A TYPE OF UNCERTAIN TIME-DELAY SYSTEMS
    年晓红
    2000, 21(4):  479-484. 
    摘要 ( 491 )   PDF (335KB) ( 306 )  
    参考文献 | 相关文章 | 多维度评价
    Some new results for stability of uncertain time-delay systems are derived and the stability degree is also discussed. Some previous results for stability and robust stability of time-delay systems are improved. Lastly, examples are included to illustrate our results.
    ON THE CRITICAL POINTS OF THE MAP Fp:X‖AXB-C‖pp
    杨长森
    2000, 21(4):  485-488. 
    摘要 ( 429 )   PDF (233KB) ( 288 )  
    参考文献 | 相关文章 | 多维度评价
    Suppose A,B and C are the bounded linear operators on a Hilbert space H, when A has a generalized inverse A- such that (AA-)*=AA- and B has a generalized inverse B- such that (B-B)*=B-B,the general characteristic forms for the critical points of the map Fp:X‖AXB-C‖pp(1<p<∞), have been obtained, it is a generalization for P J Maher’s result about p=2. Similarly, the same question has been discussed for several operators.
[an error occurred while processing this directive]
APS Journals | CSTAM Journals | AMS Journals | EMS Journals | ASME Journals