Research On Dynamic Characteristics For The Working Device Of Bucket Wheel Stacker-Reclaimer

Bucket wheel stacker-reclaimer,one type of equipment which is the largest bulk material handling machinery in the world, is widely used in the area of mining, metallurgy, electricity, transportation, building materials and chemical industry for its significant advantages. By the different structures,bucket wheel stacker-reclaimer are classified into three kinds:cantilever type,gantry type,bridge type.The cantilever bucket wheel stacker-reclaimer become the most commonly used form of structure for its flexible work structures,wide working scope and the lowly required site.This paper mainly study the cantilever bucket wheel stacker-reclaimer.In the domestic design process of bucket wheel stacker-reclaimer, as a result of the lack of scientific basis for the dynamic design,designer often bases on past experience to make a judgment.This is the main reason that domestic products has relatively poor quality and the high failure rate of the underlying.Working device is an important part of bucket wheel stacker-reclaimer,it includes bucket-wheel mechanism,luffing mechanism,revolving mechanism.The forces on the working device of bucket wheel stacker-reclaimer are complex,including Cutting resistance,blanking impact,inertia force of conveyer belt, bucket-wheel drive, luffing drive and rotary-driven rotor caused motivation, luffing inertia load and wind excitation.From the cutting action of bucket-teeth,the dynamic performance of working device will have a direct impact on bucket-teeth performance.It is difficult to guarantee that the cutting parameters of bucket-teeth are reasonable because of poor dynamic performance of working device. This, in turn, will increase from the operation targeted cutting resistance, which enabled the vibration of working device.Thereforce,studying the dynamic performance of working device,ascertaining the dynamic parameters such as natural frequencies and mode shapes,that not only provide scientific basis for dynamic design of working device,but also has an important significance for improving the bucket wheel stacker - reclaimer work performance, reducing vibration and noise, improving structural fatigue resistance and heightening the service life, reducing weight and increasing productivity.The traditional method solving such problems is using analysis mechanics with real testing. It is difficult for the method to be used in solving the problems for complex structures and large components.With quick development of computer technology, some dynamic analysis software of mechanical system which is based on rigid multibody theory, finite element method, module analysis, are used in many fields. The computer simulation has become an important method in mechanical design and analysis. This paper takes the working device of DQ800/1000.40 type bucket wheel stacker-reclaimer as an example. With the help of ADAMS and ANSYS, the example is caculated and the kinematics and dynamic characteristics of the case are obtained in this paper. The works done are as follows:1. The paper researches on the forces acting on the working device in the working process, determinates the main force(excavating force, normal force, side direction force),ignored the subordinate force(friction, impact).According to the data of model and theory, we calculated rotating velocity,pitching velocity, cutting velocity of wheel).2. According to the actual bucket wheel stacker reclaimer format, simplify structure of the model; determine the size and location between the various components. Establish models of the various components and assemble in CATIA environment.3. Through the interface documentation STL, transform the CATIA model into ADAMS format. In ADAMS environment, impose the restraints and load on the model and establish the dynamic model of working device. Through simulation, the data of forces acting on the working device in the course of reclaimer and the velocity and acceleration of weight heart in the luffing process are obtained. 4. Through the interface between ANSYS and CATIA, transform the CAD model into ANSYS format. Use the solid45 unit to mesh the model and establish a finite element model. Impose the load on the model according the result ADAMS calculating. Through the static module, ANSYS calculates that the model deformation map, node maximum displacement and stress. Identify the danger point of the structure under the first intensity theory.5. Through modal analysis of structural dynamics, ANSYS obtains the inherent characteristics of working device and the 10 bands of model type and frequency of vibration. Through harmonic response analysis,indentified the frequency of excitation in low order natural frequnencies, calculated the working device stability at the safety bucket wheel speed range.