Dynamic Analysis And Design Of Large-Scale Linear Vibrating Screen

Vibration machines are important in the industry or scientific research experiments such as vibrating screens, vibration feeders, vibrating molding machines, tamping machines, vibrating road rollers, all kinds of vibrating platforms, stimulating vibration machines and so on. These machines satisfy its technological process in producing line and working performance by its vibration characteristics. During the working process, owing to complicated bearing conditions and continuous running of long time, the equipment structure endures variable loads in operation, so the structure failures are inevitable. At present, as far as enterprises use vibrating screen, operating life of the domestic products is much shorter than that of the similar ones abroad. With the advance design and manufacture techniques, some large scale vibrating screens with excellent performances are manufactured abroad. Its un-failure time is more than 3,000 hrs, and overhaul time is more than 20,000 hrs. The same technical targets of the domestic products are much shorter than that of the products abroad. It is a pivotal subject for us to design the large-scale and heavy loading vibrating devices-especially large scaleburden machines-with high reliability and long operating life. For example, forepart fatigue rupture of primary structure pieces of the large scale vibrating screen is an extrusive question bothering engineering industry all the time. An efficient method insuring high reliability and long operating life is to adopt so advanced investigative technique that the structure can be satisfied with the dynamic load it endures and the reasonable distributing of dynamic stress.Presently the conventional design adopting still intension and kinematics analysis mostly uses the calculating method depending on experience data and safety factor. This kind of design can't accurately reveal the distributing of the dynamic stress inside the structure. Therefore the design rationality of the product's structure can't be ensured, which directly infects the use performance and life - span of the product.Taking the large scale vibrating screen as the investigative object, the author of this piece utilizes advanced means of vibration testing and dynamics analysis theory, and applies the dynamic design method combining theory modeling with experiment modeling to the dynamic design process of large scale vibrating machines. Using analysis technology of finite element, the mode parameters and the mode shape of the vibrating screen's prototype are obtained primarily. Then according to these parameters, design structures are modified elementarily to be used as the design basis of the physics experiment model and the main reference about how to dispose the experiment measuring point. Testing technology of vibration is used to found the experimental model with multiple testing points to obtain the mode parameters and the mode shape of the structure. Based on sufficient analysis of testing data, vibrating displacement field and any other dynamic characteristics are obtained .So the stress field is obtained indirectly. Modifying the model of theoretic analysis and the structural dynamics can be on the basis of these dynamic parameters. In this way, the shortage of the traditional static design method can be settled well.In this investigated subject, on the basis of the vibrating screen's working principle, the kinematics of the materiel on the screen surface and the dynamics of the vibrating screen are analyzed detailedly. Consequently technical and structural parameters of the prototype of the vibrating screen can be confirmed.Based on the destroying mechanism of the vibrating screen, the principle of choosing materials for the structural pieces of the vibrating screen and which kind of metal materials is apt to the structure of the vibrating screen are determined.In this subject, a large scale vibrating screen about 30.24M2 is taken asthe example to research and a similar physic model (similar factor 1:3) is used to go along with the research of phy...