1、英文原文Modal Characteristics and Finite Element Analysis of Screen Box forUltra-heavy Vibrating ScreenGuo Nianqin Luo LepingSchool Of Mechanical and Electronic EngineeringJiangxi University Of Science And TechnologyGanzhou, Jiangxi, China 341000Email:nfgnqAbstractThe model of ultra-heavy vibrating scre
2、en has been established by using finite element analysis software ANSYS,the stress distribution of the screen box has been revealed under static load, meanwhile, analyses dynamic characteristics of the screen box structure for ultra-heavy vibrating screen,then, has gotten the low order natural frequ
3、ency and vibration mode of the screen box, and the stress distributions and deformation in various parts of the screen box under rated load, which provided a necessary basis for the design improvement and dynamic strength study about the screen box. In allusion to the cracks of the bottom screen fra
4、me and side panels, according to the stress analysis conclusion,improve the screen box structure and change the original welding connection of the bottom screen shelf steel pipe with the side panels into flange, and this improvement gets good results in the field.Keywords- Ultra-heavy vibrating scre
5、en, screen box, FEM,Modal characteristics.I. INTRODUCTIONThe ultra-heavy vibrating screen consists eccentric-block exciter, screen box, motor, base plate and support device, which have the characters of simple structure, smooth operation, reliable work and so on. The Screen box structure takes the w
6、elding connection which is strong and reliable. It is showed in Figure.1.Besides eccentricity in the central part, each ends of the main axis are fixed with eccentric wheels. Through triangular belt, the motor rotates the exciter eccentric block at a high speed. The rotator eccentric block generates
7、 a great centrifugal force, exciting the screen box to do circular movement with certain amplitude. The spring is used to support the screen box and reduce the power passed to the base while the screen is in operation 1. II. SCREEN BOX MODELModel the 2YAC2460 ultra-heavy vibrating screen as the rese
8、arch object. There are two ways to establish finite element model of the screen box: model in CAD, then lead the solid model into ANSYS, which not only needs a long time to model, but also takes a long time to compute, and even could not get results; The other is modeling in ANSYS unit to establish
9、the finite element model of screen box. This method can build models quickly, compute fast and accurately23. A. The finite element model of screen box In order to accurately and reasonably simulate the screen box, shell63, beam188, combin14, mass21 are used tosimulate side panels, up screen frame, b
10、ottom frame, springs and exciter respectively. The Unit selection is showed in Table 1. To note that, after finished the cell division of the grid, there must be common nodes to transfer load between the junction of different thickness side panels, the junction of the side panel with the beams and t
11、he side panel with the strengthening sinew, otherwise, the locations between the plate elements as well as between the plate element and the beam element will occur separation in calculation process, leading to inaccurate results, and the failure of model establishment. Side panel is formed by a num
12、ber of surfaces, and the boundary line between surfaces is the strengthen beam. The boundary line intersection of surfaces is the connecting point of the beam to the side panels. After this cell divisionof the grid finished in the model establishment, no matter through the welding connection or flan
13、ge connection, in this model there are public nodes to represent them. In the side panel model of the screen box, the bolts and flange whose quality and stiffness have very small influence to the sieve box system, if established in the model, would bring much trouble in cell division of the grid, an
14、d effectively increase the number of units, therefore ignore them. After the model handle, we get the finite element model of screen box as showed in figure 2: B. Calculating conditions and screen containers force analysis In the course of work, the screen box bears gravity, the exciting force, the
15、spring restoring force and damping force. As for the vibrating screen is an inertia screen, in the vibration mainly the inertia force generated from the exciter eccentric mass when rotating is playing the leading role. Spring restoring force and damping force are negligible, therefore, in case of th
16、e screen Strength analysis, the screen box suffers a payload of gravity and the exciting force. The exciting force generated by eccentric block rotation:Which is equivalent to concentration acting on both sides of the side panel, then decomposed in x, y direction, the exciting force was gotten: For the simulation of the exciter, it make use of the rigid regional set in ANSYS, regard the exciter as a point mass element, a
