Finite Element Analysis And Structural Optimization Design Of High-speed Gearbox

Gear box is widely used in energy transmission as mechanical equipments. The design level of gear box reflects a country's comprehensive national strength and industrial technology level in a certain extent. With the rapid development of science and technology, people put forward higher requirements upon the gear box which is high speed, high power, light weight, small vibration, low noise, etc. The high speed gear box of the centrifugal compressor unit works in high speed environment characteristics. The gear box is supporting and positioning the gear transmission system at the same time, influenced by the gear meshing vibration. As an important part of gear transmission system, the performances of box directly affect the stability of gear system. Therefore, the research on static and dynamic performances of gear box become more important.Taking the high-speed gear box of a centrifugal compression unit as the research object, based on the finite element analysis method, the article analyze the dynamic and static characteristics of gear box. The weaker link of initial design is found out from the analysis and evaluation of calculation results. Based on the structural optimization, the structural design is made by the objective optimization method. The main research contents are:(1) According to the structural characteristics of high-speed gear box, the simplified model of the upper, middle and lower three cases of the box is built in the three-dimensional modeling software SolidWorks. The overall assembly is completed.(2) With seamless docking function of CAD/CAE, the simplified model of gear box is introduced into the ANSYS, and the establishment of the finite element model of the box structure is finished. By analyzing and calculating the force situation of gear box rated conditions, the finite element model of loading and boundary conditions has been set up. Based on the static characteristics analysis result of gear box, the maximum deformation and maximum equivalent stress of gear box can be obtained.(3) The high-speed gear box's modal analysis is carried out to extract the first ten order modal frequencies and the corresponding mode shapes in analysis results. By contrasting all transmission gear's rotation frequency and meshing frequency, the reliability of the original design dynamic performance is evaluated. The main factors and the role region of the whole body vibration will be found out.(4) Based on the static and dynamic characteristics analysis of the high-speed gear box, the design goal is selected, and the seven design variables are selected by using the optimization design module of ANSYS. Multi objective design theory is used to balance the relationship between multiple objectives, under licensing constraints of stiffness and strength of the box, the multi-objective structural optimization design of the gear box will be finished.(5) Comparing the static and dynamic performances of gear box before and after the optimization, it is found that the overall performances of the gear box after the structure optimization design are greatly improved, the quality of gear box is reduced by 152.4 kg, the maximum deformation amount is reduced by 22.8%, the low order frequency of box has been improved. The feasibility of multi objective structure optimization design will be verified by the optimization results.