Optimal Design of Large Circular Vibrating Screen Based on Multiple Frequencies Constraints and Analytical Sensitivity Methods

Multiple frequencies constraints and analytical sensitivity methods were used in structural optimization design of the side plate of 4YK1860 vibrating screen to lower the damage of side plate caused by high dynamic stress. The mass of side plate of the vibrating screen was taken as object function, mode frequencies were regarded as state parameters, size of plate were used as constraint parameters and an optimization criterion which is applicable to solve this kind of problem was given. Meanwhile, sensitivity characteristics of variable parameters were considered during the process of optimization. The results show that the optimization program with embedded analytical sensitivity calculation methods is of a higher solving precision and with a more stable calculating process. After structure optimization, the thickness of side plate to withstand large impact is increased, the thickness of stiffener and peripheral angle are decreased, the mass of side plate is reduced by 7.75% and a better optimization effect is achieved. The analysis of the optimal vibrating screen presents that the mass of vibrating screen decreases by 3.5%, elastic deformation frequency which is close to the working frequency increases by 8.8% and the dynamic stress decreases by 48%. The natural frequencies of vibrating screen are improved and modal frequency is far from the working frequency of the exciting motor, stress concentration of vibrating screen is weakened and thus the structural stiffness and reliability of vibrating screen is enhanced.