（節(jié)選）振動篩外文翻譯---大型振動篩動態(tài)設(shè)計理論與應(yīng)用（原文）

1、 Procedia Earth and Planetary Science 1 (2009) 776–784 www.elsevier.com/locate/procedia=The 6th International Conference on Mining Science reliability; hyperstatic net-beam structure; finite element; dynamic optimizati

2、on 1. Introduction The structural strength and stiffness needs to be improved with the maximization of screening machines. The enlargement of structure of vibrating screen will lead to the increase of vibration mass and

3、exciting force. Dynamic load on the vibrating screen is also increased which will lead to a greater deformation, tear of the side plate, fracture of the crossbeam, and thus affects the service life of the vibrating scree

4、n seriously[1-3]. Conventional static strength calculation and analogy method was used in the design of vibrating screen in our country at present which neglect the dynamic characteristic influence of higher modal freque

5、ncies on the vibrating screen[4]. High exciting force is likely to lead to fatigue damage of vibrating screen. Engineering experience indicates that the screen can also be ? Corresponding author. Tel.: +86-516-83590092.

6、 bJã~áä=~ÇÇêÉëëW ymzhao@cumt.edu.cn. 187 - /09/$– See front matter © 2009 Published by Elsevier B.V. doi:10.1016/j.pro .2009.09.1238 5220epsProcedia Earth and Planetary

7、Science = =The structure and load on the vibrating screen should be considered according to actual operating condition to make the finite element model accurate and effective. The main structure adopted solid element SO

8、LID95 and SOLID92.The spring used COMBINE14 and the vibration generator was simplified as lumped mass element MASS21.The imaginary beam was introduced to replace the flange, considering the stiffness of flanges and ign

9、oring its mass. The bear was simplified as sleeve and the exciting force distributed on the inner face of the sleeve uniformly. The finite element model was finished in ANSYS, as shown in Fig 3. Fig. 3. Finite element

10、model of vibrating screen PKOK k~íìê~ä=ÅÜ~ê~ÅíÉêáëíáÅ=~å~äóëáë=Natural characteristic is composed of natural f

11、requency, natural vibration modes and other modal parameters. One purpose of natural characteristic analysis is to avoid resonance and harmful vibration mode. The results is also used to provide necessary basis for dyna

12、mic response analysis[8]. Block Lanczos method with high precision and computation speed was used solve natural characteristic. The first twelve modal results are shown in Table 1. Table 1. Modal calculation results of

13、 vibrating screen Set Natural frequency Ñ=(Hz) Natural modes of vibration 1 1.66 Rigid motion along z axis 2 2.88 Rigid motion along x axis 3 2.92 Rigid motion along y axis 4 3.43 Rigid rotation around y a

14、xis 5 3.94 Rigid rotation around x axis 6 4.18 Rigid rotation around z axis 7 14.85 Bending and swing of discharge end along y axis 8 16.92 Twist of side plates along y axis and swing of feed end along z axis 9

15、18.98 Twist of screen frame along y axis 10 23.54 Reversal around x axis and bending of screen along z axis 11 33.41 Bending and twist of feed end along x axis 12 36.45 Flexural oscillations of middle and back of

16、the screen along z axis Table 1 show that the natural vibration modes include rigid motion and bending deflection. The first six vibration modes are rigid modal and modal frequency is lower which depends on the vibration

17、 mass and stiffness of spring. The seventh to twelfth vibration modes are deformable modes and modal frequency lies on structural stiffness of the vibrating screen.The seventh to tenth vibration modes are shown in Fig

18、4. From Table 1 and Fig 4 we know that there are two elastic modal around the working frequency, that are the seventh and the eighth modal which take a central part to the total deformation of the vibrating screen and ar

19、e easy to lead to resonance. The seventh modal frequency is 14.85Hz, the bending and swing amplitude of the discharge plate is greater, of which the maximum deformation reaches 4.25mm. The result shows that the intensi

20、ty of the discharge end is weaker and the structure is easy to break. Thus the structure of discharge end needs to be modified. The eighth modal frequency is 16.92Hz, the deformation of connection part of two side plat