| As one of the most important operation equipment,the belt conveyor has developed nearly150years in the modern industrial and mining industry, because of its conveying capacity, simple structure, convenient repair, low cost, strong versatility, stable operation and continuous operation ability, it has widely used in metallurgy, coal, transportation, power, chemical industry and the other departments.With the rapid development of the global economy and industrial technology, the belt conveyor’s direction towards to long distance, large capacity and high speed. This kind of belt conveyor brought numerous technical problems during greatly improved production capacity, so the performance and dynamic characteristics of the belt conveyor is more obvious, and in order to adapt to this trend of development, studying the dynamic characteristics of the belt conveyor is necessary.This paper is based on the belt conveyor system dynamics theory, the theory of ADAMS rigid body dynamics and ADAMS flexible body dynamic theory, and using the experiment conveyor as model, by simplifying and assuming, two methods were used:the rigid band block modeling method and flexible block modeling method. Using the dynamic simulation software ADAMS to set up an overall machine model and a model of belt of conveyor. Through the simulation, in different modeling methods, choosing the most reasonable Harrison speed starting curve, we know the changes of the state of drum meeting point dynamic tension and speed. The simulation process shows, belt conveyor model that established by the rigid band block, compared with flexible block, the transport cycle and belt speed fluctuation are longer, and the fluctuation amplitude is relatively large, thus the belt speed may appear strong surge characteristics, and also will be quite intense, at the same time will reduce the transmission efficiency of belt drives. And through the simulation comparison with the results of theoretical calculation we can find that the model with flexible block modeling way than rigid results is more close to the theoretical value.Based on the above analysis and modeling, the self advancing tail forward is simplified as the tail roller moved forward, and simulate this process by the model of the belt conveyor flexible block in ADAMS dynamics software. Through the principle that parts instead of the whole, picking conveyor section of several key parts of the tail roller, driven roller, tension device and roller, we can find the change of dynamic tension during the shift in the tail of belt conveyor, along the transmission line. The simulation process shows, drum forwarding will cause excitation on the belt, and a tension wave, and during the transfer process. During the loosing and tighten conveyor belt process, the changes of the tension in the tail and head are larger, and changes in the tension at the loosing process are larger, while in the tighten process the tension change is smaller, and the change of nearby tensioning idler front changes a little.The above analysis shows that, the flexible belt is better than the rigid belt in fitting a conveyor belt model and is more suitable for the flexible belt fitting, thus more accurate to simulate the dynamic characteristics of the belt conveyor. And there are four results in a tail roller movement (1)tension wave in conveyor belt will occur(2)the tension caused by wave will spread along the conveying line conveying belt, and spread by the descending form(3)the tension wave in the process of communication, will cause the large impact in the belt conveyor tail and head(4)while in tension apart, because of the tensioning weight, the smaller changes in process of tension during tighten process, and this is precisely that the hammer tensioning device has the ability of removing some of the impact load. |
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