Numerical Simulation And Optimization Design Of Heavy Load Rolling Bearings

Heavy load rolling bearings are the key load components in large equipments, which work under high stress, low speed and insufficient lubrication. Less work was done on rolling bearing's design considering the special requirements. Therefore, in this work, Finite Element Analysis (FEA) and optimal designs of heavy load roller bearings are completed.FEA is a widely used numerical method to execute fast calculation on complex structures. To carry out the explicit dynamic analysis of the roller bearing, a 3D solid model is built in the environment of ANSYS LS-DYNA. Applying different material models, such as the elastic material model and the plastic material models, motion pattern, stress distribution and shaft's displacement in radial displacement are calculated. The influences of different material models on calculation results are discussed. The plastic material models were proved to be more suitable for the case of heavy load compared with the elastic material model. The reasons for motion failure and problems to be solved are also included in this FEA simulation section.The method of optimization design is explored with regard to two types of bearings suitable for heavy loads. Constraint multi-objective genetic algorithm(Fast Non-dominated Sorting Genetic Algorithm,NSGA-II)is applied in this work, as it is able to avoid trapping in local maximum. Optimal design on toroidal roller bearing is realized, in which inner geometry parameters are considered as design variables, while the static load rating, fatigue life, wear life and high stress at roller ends are chosen as objectives. After defining the constraints according to geometry and strength requirements, non-inferior solutions are obtained and the optimal design is selected among them. Certain verifications of the result are done in the way of calculating the static stress by FEA as well as calculating the dynamic load rating of the final design.Finally, the main shaft bearing of the 700TM manipulator is designed. Tapered roller bearing is chosen as the basis for further optimal design. Inner geometry parameters are deemed as design variables. The four objectives are static load rating, fatigue life, wear life and maximum stress in the rib respectively. Constraints on variables are estimated according to geometry and strength concerns. The optimal design was verified in the way of calculating the static stress by FEA as well as calculating the dynamic load rating.