Applying hybrid dynamic substructure synthetic method to dynamic analysis for tower crane

This paper presents a dynamic hybrid substructure synthetic method for tower crane dynamic analysis. This method employs the transfer matrix method and the flexibility degree method respectively to formulate the vibration mathematical models of the tower body and tower top system substructures in the hoisting luffing plane. Based on the motion of the substructures in the interface and the dynamic harmonize condition, the frequency equations are established. Then the program is designed according to the mathematical models and firstly applied to the dynamic analysis of the QTZ63 tower crane in the construction site and the parameter identification of attached device and tower body. The test results show that the value calculated by the above method is quite approximate to the instrument measured value, which can meet the engineering requirements. Further study has found that , for the flexible long-distance attached tower crane, the method that introduces dynamic load coefficient for statics analysis of tower cranes is unprecise enough since there exist errors.This paper suggests to conduct site test and identification of the rigidity coefficient of attached device of the tower crane for the accident prevention of tower crane collapse by timely take measures.     

Model Analysis of Tower Crane Structure Based on ANSYS

In this paper,a complete dynamic model of the tower crane is set up by the finite element software ANSYS and then the QTZ25 tower crane model is calculated.Through comparing the results,the feasibility of this method is proven.This method is a new approach to fast and precise analysis on dynamical model of tower crane structure.     

THE COMPUTER AIDED DESIGN SOFTWARE SYSTEM FOR THE STEEL STRUCTURE OF TOWER CRANE

This paper introduces the main structure and function,the theor-etical basis and the main features of the computer aided design software system QT-SCAD for the steel structure of tower crane.The QT-SCAD is suitable for allkinds of movable or fixable tower crane with level arm which rotates above thecrane body,and has single or double hanging points.It can be used for the stre-ngth,stiffness and stability analyses of the structure,the vibrative and dynamiccalculation of mechanisms and structure,and the optimal design of the structureof tower crane or its components.     

COMPUTER-AIDED ANALYSIS AND DESIGN FOR THE BASE STRUCTURE OF A MOVABLE TOWER CRANE

This paper is one of the achievements of the researchitem for computer-aided design of tower crane's steel structure.In thepaper,taking the well-base structure as an example,first the method establishing the mechanical model is explained for the base structure ofa movable tower crane.Then the math model of its optimal design andthe N-S figures for the computer program is described and calculatedusing discrete optimal technology.Finally the problems related to thedesign for the base structure of a movable tower crane are briefly illu-strated.     

Dynamic characteristics analysis of megawatt wind turbine drive train

Since the wind turbines are installed on the flexible support tower, the drive train of the wind turbines runs under severe work conditions with varying wind directions and loads. So its failure rate is high and it is the bottle neck of the wind power development. This work presents a study which takes the coupling effect of oscillating of tower barrel and the twisting vibration of driven train into account. Using the lumped parameter method, a coupled dynamic model for the megawatt wind turbine drive train is built by considering the flexible tower barrel support effects. Then, the dynamic characteristics of the megawatt wind turbine drive train are analyzed. The Campbell chart is used in this research to analyze the potential resonance points. And the potential resonance frequencies between the cutting in and cutting out rotational speed of the drive train are obtained. Finally, Simpack is used to analyze the dynamic characteristics of drive train and verify the correctness of the proposed method.     

刚性连体位置对非对称双塔连体结构动力可靠度的影响

考虑地震动的非平稳性,变化连体位置,对非对称双塔连体结构运用虚拟激励法进行非平稳随机激励下的动力可靠度研究。采用刚度退化的Bouc-Wen模型模拟塔楼各楼层的滞变特性,建立非线性化动力方程。运用混合精细积分法对每一时刻的响应进行求解,得到连体位置变化时非对称连体结构在非平稳随机激励下的时变方差。基于首次超越破坏准则与Markov假定,研究非平稳随机地震激励下连体结构的动力可靠度。运用上述理论,在8度罕遇地震作用下对某非对称双塔连体结构进行随机地震响应与动力可靠度分析。研究结果表明,地震作用下结构的层间位移响应呈现强烈的非平稳性,变化连体位置对连体结构的随机地震响应与动力可靠度将产生显著影响。     

THE DYNAMIC MODEL AND OPTIMIZATION OF A NEW DYNAMIC VIBRATION ABSORBER

A method of forming the broadband dynamic absorber by paralleling two absorbers is proposed in view of the characteristics of the narrow suppression range of the traditional absorber. The formation of its dynamic model and optimization are studied as well.     

A Study on Input Excitation for Simulation System of the Hoisting Mechanism of a Crane

In this paper, a model has been set up and S function of input excitation is used to simulate the dynamic performance of the hoist mechanism of a crane driven by asynchronous motor. A comparison is given between different displacements and dynamical load responses obtained by different input excitations.     

THE FUZZY OPTIMIZATION DESIGN OF BOX EXPANSION ARM OF CRANE TRUCK

In this paper the section sizes of box expansion arm of crane truck are optimized in order that the weight of the arm will be the lightest on conditions that strength, rigidity, stability and size constraints are satisfactory. The fuzzy factors which influence design and the fuzziness of constraint conditions are considered. The unsymmetry mode of fuzzy optimization is established and solved by the method of optimal level cut set. Examples show that the effect is notable.     

高效低耗的粮食烘干机研制与试验报告

根据粮库的需要研制和开发了高效低耗的新型粮食烘干机，介绍了该机的主要特点、总体结构及工艺流程等方面，尤其对干燥塔、炉灶进行了详细介绍。简述了烘干机的具体应用。     

Structural Optimum of Main Tower- Frame of Mast Crane

Taking the Structural optimum of main metal frame of mast- crane as a sample,this paper discussed the method of Structural optimization of common middle & high flexibility metal tower- frame by dynamic programming.The method of dynamic programming applied to the structural optimum was deducted and the minimum weight design method of tower- frame was practiced The paper gave up the traditional interactive way of choosing type of material,combining with the concrete example,changed the data- table looking up into formula solution,shifting with one by one into directly sieving within selected types,artificially fixing up composed rods into automaticaliy arranging them through the way of maximum twist moment of inertia,thus,accelerate optimization and offered a short way for artificial structural analysis and calculation.     

大豆烘干与储藏综合管理

文章从大豆太仓前的清理,烘干塔参数的控制,合理通风,倒仓,大豆温度和水分的监控,仓内灭菌以及储存期的控制,介绍了应用烘干技术和波纹钢板仓储藏技术对大豆进行综合管理。     

9种鹤类DNA条形码的研究

为了研究9种鹤类的DNA条形码,采用DNA条形码鸟类通用引物扩增中国4种鹤类（22个个体）的线粒体细胞色素C氧化酶亚基I（COI）基因。从GenBank及BOLD Systems下载13条鹤类的COI基因序列,对35条COI序列进行分析,构建NJ树和MP树,探讨DNA条形码对鹤类的识别和鉴定。结果显示,丹顶鹤群体中,除D1和B18号个体外,均被归为同一类群;白鹤群体中,编号为AY567881的个体与黑鹤划为同一类群;其余鹤类的系统发育分析结果均与形态学分类结果相同。由于丹顶鹤样本均取自沈阳森林野生动物园,所以是同一物种或是近缘物种杂交的可能性最大;白鹤较大的种内差异则可能是地理位置或是其他原因。     

Dynamic Simulation on the Hoisting Mechanism of a Crane

Considering the difficulties of mathematical analysis and the complex computer programming of numerical methods in solving dynamical problems of the multi-body dynamic system for the hoisting mechanism of a crane, in this paper, a multi-mass-multi-freedom model is set up and the simulation system of the model is built up applying MATLAB/SIMULINK toolbox. The differential equations of the model is solved with adaptive-step fourth-order Runge-Kutta method. In the study, the typical work conditions of the hoisting mechanism, such as start rise from ground, start rise/down in air, brake conditions, were simulated. The dynamic performance of the hoisting mechanism is studied and the results obtained are valuable to practice. This study improves the modeling accuracy of the hoisting mechanism and the results of precious theoretical analysis and numerical computation conclusions. The movement of every discrete body of the system can be modeled applying the methods suggested by this study and more consistent results between model and actual hoisting mechanism can be achieved.     

Structural Model and Cargo-handling Technology of the Quay with High Amplitude of Water Level in Lantsang

The background of a west communication science & technology project whose topic is structural model and cargo-handling technology of the quay with high amplitude of water level in Lantsang is introduced, and its main research content, research of key technology and main findings are introduced too. Three types of structural model and cargo-handling technology which can be applied perfectly in Lantsang are put forward. The structural models include beam and slab structure with pillar supported, box bridge crane structure and reinforced earth structure, the cargo-handling technologies include vertical fixed crane technology, bridge crane technology and movable simple crane technology. Some findings have been applied in the supporting engineering-Menglun harbor.     

模式识别的斜拉桥损伤诊断动力指纹与识别算法

为有效并准确诊断出斜拉桥损伤,对基于模式识别的斜拉桥损伤诊断方法进行了研究。选取易于测试出的低阶模态频率和部分关键点竖向振型数据为动力指纹,无需模态扩展或模型缩聚。研究并采用全因子设计进行动力指纹库的创建,可精确评估设定的损伤因子及其交互作用对损伤识别结果的影响。设计并增加了带随机误差的动力指纹库样本集。编制了基于Matlab的模式识别的多种算法,重点研究了精确度高的多层感知器识别算法及其提高该算法预测准确率的装袋集成算法。最后给出一座单塔双跨双索面斜拉桥的多种识别算法的损伤诊断过程和结果,得到一种可包容测试随机误差的高精确度斜拉桥损伤诊断评估模型。     

A Calculation Method of Hawser Forces in Loading and Unloading States

In this paper,several calculation methods for hawser cables as the crane stability system in loading and unloading forces is put out by coordinating principle of deformed body.It is convenient for adjustment of crane in unloading state to benifit accurance of the equipment installation and safrty of device during hoisting.It is also a more accurate and practical method for choice of the cable.     

Modeling and simulation of a grid connected wind turbine withdoubly fed induction generator

In order to fully research the effects of external excitations, such as wind speed, wind direction and voltage disturbance, on a grid connected wind turbine with doubly fed induction generator, a co-simulation model of MW-class wind turbine system is established by using Simpack and Matlab/Simulink software. Also, by considering the actual control strategies in the process of simulation, the relationship between external excitations and mechanical system is studied. According to time-domain simulation under the turbulent wind condition, the dynamic meshing forces of gears are analyzed. Besides, the vibration responses of tower are calculated under the different external excitations. Research results lay a foundation for dynamic performance optimization and reliability design of a wind turbine.     

Transverse Seismic Design and Analysis of an H Type Bridge Tower Cable Stayed Bridge

According to our current bridge seismic design codes, the bridge tower is explicitly required to remain almost elastic even under the excitation of occasionally happened earthquake. To achieve this seismic performance objective, usually the steel ratios of tower base and strut are required to satisfy the static loading demand and increase by a large margin as well in most engineering practices which leads to engineering inefficiency as well as a rising seismic demand for the substructure. Therefore, the structural design parameters including the location, the stiffness and the constrain condition of the strut with respect to the tower column of H shape tower were studied to explore their effect on the transverse seismic responses of cable-stayed bridge tower, Moreover, the effect of yield intensity of the strut on the seismic responses of the tower column is also studied. The results show that the location and the stiffness of the strut have a slight effect on the seismic responses while the transverse seismic demands of the bridge tower decrease drastically when the constrain condition between the cross beam and the tower column changes.