共查询到20条相似文献，搜索用时 390 毫秒
1.
In this paper, a constitutive function in form of integration is presented for a nonlinear analysis of structures of linear elements. With applications of a constitutive function, the truss and frame elements material nonlinear stiffness equations are derived. The results shows the convenience in numerical analysis and the ability to solve some difficult problems in tn the structural behavior study both in loading and unloading process by use of the presented constitutive function. 相似文献
2.
Tang Zhuoyao Ren Zhen Wang Guanjie Lou Dianqiang 《保鲜与加工》1998,(1):43-48
For Passive Active Hybrid filtering system on the DC side of HVDC system, the controller based on Hysteresis method is presented, and the corresponding control circuits are also designed in this paper. Simulation results show very fast dynamic response and excellent compensating performance by using the proposed controller and the designed circuits. 相似文献
3.
For requirements of suppressing harmonics on the dc side of HVDC system,a new hybrid filtering system a shunt passive and a small rated reactor transformer coupling series active filter is presented,and the harmonic compensation and control principles are discussed theoretically in this paper.Digital simulation results show excellent filtering characteristics of harmonic current and very high performance/cost by using a new hybrid filtering system proposed int this paper. 相似文献
4.
Yun Zhengqing Tan Bangding 《保鲜与加工》1993,(5):79-84
Based on [l].this paper presents a new spline-BEM for calculating 3-D electrostatic fields,in which bi-cubic B-splines are used as basis functions. The corner problem in BEM and the extreme conditions for splines are circumvented. The numerical results presented show that the global approximation .convergence and stability of the method are satisfactory. 相似文献
5.
Liu Wencai Yang Yongzhen 《保鲜与加工》1990,(3):20-26
A controller employing self-tuning control and feedforward technique for high precision control of high temperature electric furnaces is presented in this paper. The mathematical model of these furnaces and the whole control algorithms are discussed. Experimental results have proved the effectiveness of
ibis controller. 相似文献
6.
In this paper,the conception of bus voltage stability control area of local powersystem is presented,based on the practical criterion for voltage stability calculated by the real-timeinformation and the quasi-real time information form the power system.The method is test6d onIEEE-30-bus test system and results are satisfactory. 相似文献
7.
The number of hotel buildings increased rapidly in Chongqing with the fast development of its economy.This paper presents the electricity consumption audit of 9 typical hotel buildings in Chongqing.The electricity consumption characteristics of hotel buildings in Chongqing were analyzed.Test results of a typical four-star hotel in summer of 2004 are given and some conclusions and suggestions are presented. 相似文献
8.
In this paper,the flow velocity fields,suspended solids concentration fields and flow-through curves in rectangular sedimentation tanks with different reaction baffles location,inlet horizontal velocity and length height ratio are simulated in detail using a developed mathematical model given in Reference 2.According to the numerical results,the influence of different reaction baffles location,inlet horizontal velocity and length height ratio on the operating efficiency is analyzed.Finally,the rational reaction baffles location,inlet horizontal velocity and length height ratio are presented. 相似文献
9.
Zhou Bo Zhao Jianfeng Yang Jun 《保鲜与加工》1999,(2):81-86
In order to decrease the current ripple and improve the operating performances of the rare earth permanent magnetic brushless DC motor system,a two quadrant current chopper is used in the system and its operating principles are analyzed in this paper.The results of digital simulation and system experiment are presented and confirm that the system based on the two quadrant current chopper has attractive performances. 相似文献
10.
In this paper,a new method of water flushing recovery of waste glsss is presented. The equipment of separation of glass from waste materials and it' s mechanisms are described.The relationship between the efficiency of separation of glass from waste materials and the physical and mechanical properties of these waste materials is analyzed. The experimental results of recovery of waste glass are given. It is found that the efficiency of recovery of glass is more than 90%. 相似文献
11.
In this paper,the analytical solutions for an elastic rectangular thin plate with opposite boundary completely clamped support and others free were derived by a Symplectic geometry method.Due to the fact that the basic elasticity equations of the thin plate were only used,it was not necessary to select the deformation function arbitrarily.Therefore,the solutions in this paper are much more general mathematically.In order to prove the validity of the formulations,numericam results were presented to be compared with those derived by other references. 相似文献
12.
A novel approach to modelin8 resonant conventers, was presented in this paper.The variant subtopologies of a converfer are unified into an equiualent topology by the periodicpulse functions;Laplace transforms of the sampled function ,insteady of continuous ,of a small sig-nal variable are made;furthermore,the linear approximation is processed according to the differenttypes of converters, The conventional series and parallel converters are used as examples to discussthe principles of the approach. Finally the computer calcultion data is compared with the experiment results to con firm the models to be correct. 相似文献
13.
A NEW DISCONTINUOUS CURRENT MODEL FOR SCR DC MOTOR SPEED CONTROL SYSTEM AND CURRENT ADAPTIVE CONTROL
Luo Xian-zhi Meng Xiao-feng 《保鲜与加工》1988,(6)
The paper presents a new approximative model suitable to discontinuous current and continuons current in the three-phase controlled bridge rectifier DC motor control system. This model offers a new approach for discontinuous current adaptive control.As an example of application of the model, digital simulation results of discontinuous current adaptive control in a double-closed-loop control system are presented. 相似文献
14.
Perturbation Analysis of Complex Modes for Vibration System with Viscous Damping and Its Application
Deng Zhaoxiang Liang Xichang He Yusheng 《保鲜与加工》1997,(2):1-9
The sensitivity characteristics of the undamped natural frequencies and complex mode shapes of vibration system with the non-proportional viscous damping with respect to structural mass, stiffness and damping modifications are analyzed in this paper using the matrix perturbation of complex modes. The general principles for the selectivity of the design and the most sensitive positions of the structural perturbation modifications are shown thereby. This is of importance to a great computational savings in the dynamic characteristic improvement of large or complex structures. By the dynamic characteristic sensitivity analysis of a test device type RDT-1,the optimal structural design for its especial requirement of dynamic characteristics is obtained easily and the principles presented in this paper are confirmed by the numerical results of perturbation analysis. 相似文献
15.
16.
On the Iteration of Fixed Points for Generalized Quasi-contractive Mapping in p-convex Metric Spaces
The purpose of this paper is to define an Ishikawa iterative scheme for generalized quasi-contractive mappings in p-convex metric spaces and to prove that this iterative scheme converges to the unique fixed point of generalized quasicontractive mappings in p-convex metric space. The results presented in the paper generalize and unify the corresponding results in given by Liu Qin-hou, Xu Hong-kun, Ding Xie-ping, H. E. Rhoades, et al. 相似文献
17.
A computer method for comprehensive comparison between EHVAC and EHVDC is presented in this paper after analyzing the fundamental characteristics and studying the design methods of these two types of transmi-sson schemes. Some formulas are developed and an appropriate mathematical model is established. A generally applicable computer program is exploited which is acceptable to IBM-pc and its compatible micro-computers. The results of numerical practical project of the program are given to prove the correctness of the model and the program described in this paper,and it also shows that the method proposed is an efficient one with the practical values in power system planning. 相似文献
18.
Based on the measured data from the construction site, the prediction uncertainty of the CEB FIP MC90 due to the variation of the calculation parameters (i.e. the external uncertainty) and their sensitivity are analyzed with the help of statistical method and Latin Hypercube sampling method. Three conclusions can be deduced from the analysis. Those are a)the external uncertainty and its decreasing rate of the CEB FIP MC90 reduce with the time increasing, b)the creep coefficient increases with the increasing temperature while decreases with the increase of other calculation parameters, c)in accordance with the degrees of effect to the creep uncertainty, the first three calculation parameters are relative humidity, loading age and temperature, if the variation of the loading age is not taken into acount, the uncertainty of the creep pridection will be underestimated. Also, a method to analyze the uncertainty of the bridge structure due to the creep prediction uncertainty is proposed after the creep uncertain factor, which is the standard of the uncertainty of the creep, is introduced. An exmaple is analyzed in this paper using the random sampling method and the method presented in this paper. Through drawing a comparison between the results from different methods, the method presented in this paper appears to be feasible and efficient. 相似文献
19.
Zhu Jingmin Chongqing Institute of Architectute & Engineering Wang Jiayuan Shenzhen University 《保鲜与加工》1989,(2)
In this paper,the theological model is presented,and the ba-sic principle of the viscoelastoplastic problem is worked out by the boundaryelement direct method,and the relevent formulations are derived.Several exam-ples show that the theological model and the corresponding boundary elementmethod presented in this paper are effective and reasonable. 相似文献
20.
It is still a major problem for research on online monitor dielectric dissipation factor of high voltage equipment insulation. In the field, new methods are paid attention by researchers especially. At present, there are no methods achieving the satisfactory measurement results. Based on the voltage and current at their respective zero crossed points, this paper proposes the integral measurement method which can be used to measure the dielectric dissipation factor of high voltage capacitive apparatus. The formula for dielectric dissipation factor angle computation is deduced by theoretical analysis and the computation results are achieved by digital simulation. Meanwhile, this paper explains the effect to measurements by system frequency, content of harmonic and zero-drift and draws the relevant error curves. It also proposes the measures to reduce the integral measurement method presented in this paper,which can convert measurement of small signal into that of big signal and accurately measure dielectric loss of capacitive apparatus. It also possesses great anti jamming ability under strong electromagnetic interference environment. The online measurement system can detect the dielectric dissipation factor of high voltage equipment by the integral measurement method. 相似文献