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.     

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.     

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.     

The sustainability of the common crane (Grus grus) flock breeding in Norfolk: insights from simulation modelling

VORTEX computer simulations were used to assess the viability of a small breeding flock of common cranes, recently established in Norfolk. Investigations were also conducted on the relative impact of various management options. Raising the carrying capacity of the site had little influence on the survival of the flock. However, great improvements were associated with increases in the size of the founder flock and reductions in the mortality rates of chicks and adults. Regularly supplementing the population increased flock survival times: for a fixed total number of birds added, frequently supplementing with few birds produced the best results. Immigration from the population in continental Europe also increased persistence of the flock, and it is possible that immigration rates will improve as the British flock expands. Strategies including captive breeding, and regular supplementation of the flock, may be the most effective means of ensuring the viability of the Norfolk cranes. The potential value of simulation models in guiding management of small populations is discussed.     

PLC在高架吊中的应用

PLC(可编程序控制器)是一种专门为在工业环境下应用而设计的自动化装置之一。它具有高可靠性高和性能好的优点，在自动化程度要求高、环境恶劣、危险的场所得到广泛的应用。高架吊就是可编程序控制器应用的一个典型例子。为此，介绍了西门子公司S5-135U型PLC在HMK26E高架吊中的应用及其工作原理。     

林用装卸桥小车非正常运行研究

对林用装卸桥小车在作业中出现的非正常运行情况，即啃道、跑偏及轮馏面与轨道的接触长度太短等情况进行了研究，并提出了切实可行的对策。     

论林用门式起重机技术条件

本文分析研究了林用门式起重机的技术条件,技术条件中包括对林用门式起重机的机械件、钢结构件和电器装置等的要求。介绍了林用门式起重机的现状及未来的发展。     

鹤式起重机三维建模及运动特性分析

基于四连杆机构理论,在UG环境下搭建了简化的鹤式起重机三维实体模型,并运用ADAMS软件对其进行了多体动力学运动特性仿真.为改进其结构设计和减轻自重做出了有益的探索.     

Which uncertainty? Using expert elicitation and expected value of information to design an adaptive program

Natural resource management is plagued with uncertainty of many kinds, but not all uncertainties are equally important to resolve. The promise of adaptive management is that learning in the short-term will improve management in the long-term; that promise is best kept if the focus of learning is on those uncertainties that most impede achievement of management objectives. In this context, an existing tool of decision analysis, the expected value of perfect information (EVPI), is particularly valuable in identifying the most important uncertainties. Expert elicitation can be used to develop preliminary predictions of management response under a series of hypotheses, as well as prior weights for those hypotheses, and the EVPI can be used to determine how much management could improve if uncertainty was resolved. These methods were applied to management of whooping cranes (Grus americana), an endangered migratory bird that is being reintroduced in several places in North America. The Eastern Migratory Population of whooping cranes had exhibited almost no successful reproduction through 2009. Several dozen hypotheses can be advanced to explain this failure, and many of them lead to very different management responses. An expert panel articulated the hypotheses, provided prior weights for them, developed potential management strategies, and made predictions about the response of the population to each strategy under each hypothesis. Multi-criteria decision analysis identified a preferred strategy in the face of uncertainty, and analysis of the expected value of information identified how informative each strategy could be. These results provide the foundation for design of an adaptive management program.     

铁路起重机安全监控装置研制

介绍了一套铁路起重机安全监控装置,该装置可对铁路救援起重机在起吊作业中的重心偏移进行实时监测,当发生危险情况时能立即报警并停止起吊作业.