Application Of Similarity Theory In Vibrating Screen Series Design

The theory of similarity design promotes the improvement and innovation of the product to some extent. Nowadays, this theory is applied in many aspects, such as fluid mechanics, heat transfer, ship mechanics and aviation dynamics, but the theory is seldom used in the design of vibrating screen. This thesis mainly aimed at the vibration screen, research on similarity based on similarity theory, a series of design methods for the design of the vibrating screen is found, and, the similar design condition of the vibrating screen is put forward.The product series design of vibration machinery is very heavy. In this paper, the similarity theory is introduced into a series of design work. taking a specific product as the prototype(vibrating screen as an example), a series of design is carried out. the similarity criterion of the vibrating screen was deduced. make the series design more scientific and effective. The main contents of the research are as follows:(1) The research on the similarity theory to the product design method of the guiding ideology, the research status of similarity design both at home and abroad is discussed, the development direction of the similarity design theory is analyzed, the feasibility and economic benefits of the similarity theory in the design of the series of vibrating screens are pointed out.(2) On the basis of discussing three theorems of similarity theory, three methods of deriving similarity criteria are analyzed, namely, theorem analysis, equation analysis and dimensional analysis. The advantages and disadvantages of three methods are summarized, finally, the method of determining the similarity of the vibrating screen is determined by using the method of the amount of the method.(3) The similarity criterion of the physical parameters of the vibrating screen was deduced by the dimensional analysis method,and the dimension matrix is established. π factor is obtained by the dimensional matrix, and the expression of the similarity constant of the physical parameters is further established. Taking cantilever beam with different section shape as an example, the correctness of the similarity constants of the physical parameters is verified. Then, the main parameters affecting the performance of the vibrating screen are analyzed, by optimizing these parameters, come to the best prototype. Finally, according to the similarity ratio r and the similarity constant,a similar model vibrating screen was established.(4) The use of finite element software, modal analysis of the vibration screen and the prototype vibrating screen is carried out, six natural frequencies and vibration modes of the first order are obtained. And the difference of the similarity constant is calculated, the difference between the vibrating screen and the vibration screen is obtained, through analysis,the reason of this difference is that the model is simplified and the structure and the supporting plate are increased. Finally, the harmonic response is analyzed, the dynamic stress and strain of the model vibrating screen at the frequency of 16 Hz are obtained, through comparison with the prototype vibrating screen, the correctness of the similarity criterion and the similarity constant are verified. And the strain satisfies national standard allowable value.(5) The kinematic parameters and design parameters of the vibration screen are analyzed, the amplitude and the excitation frequency and the thickness of the plate were chosen as the experimental factors for the orthogonal test. 9 sets of experimental data were obtained. Data processing and analysis of variance showed that, within the range of parameters studied, the amplitude of the vibration screen is the most influential, secondly, the thickness of the plate, the vibration frequency is the least. So, in the premise of reducing the cost of vibration screen production, through orthogonal experiment analysis, the optimal design scheme is the excitation frequency of 16 Hz, the amplitude of the screen box is 4.5mm and the thickness of the plate is 10 mm.