Application of Evolutionary Algorithms to the Optimal Design of Non-circular Actively Lubricated Bearings

The paper presents an approach to the optimal design of actively lubricated hybrid bearings with non-circular bore geometry. The novelty of the proposed approach is the automated and joint assessment of the performance of the active lubrication system and the nonlinear dynamic behavior of the rotor on the designed bearings, also considering their non-circular bore shape. The optimization problem is solved by several evolutionary algorithms, including MOGA, NSGA-II and MOPSO to compare their efficiency. Also, a new variation of MOPSO algorithm with the modified method for selecting leading solutions was proposed to improve the quality of solution. Since the calculation results are represented by a three-dimensional Pareto front, several solutions with different specified properties are analyzed, as well as an approach to selecting a single solution using the linear convolution method. The results of comparative analysis of the applying the considered evolutionary algorithms are presented. In particular, the time spent on performing calculations, the degree of minimization of objective functions, as well as the variety of Pareto-optimal solutions obtained were compared. The results obtained allow giving recommendations regarding the application of the considered approach and algorithms to the optimal design of active fluid film bearings.