Study Of Structural Lightweight For Megawatt-level Wind Turbine Gearbox

As a kind of clean and renewable energy, wind power has attracted great attention of people, which leads to the rapid development of wind power generation industry. The structure of the wind power gearbox which works in the high-altitude tower is complex. Because of the use of side support and its large transmission ratio, the gearbox has poor rigidity and a high failure rate. The key technology of wind turbine gearbox has been an important factor in the rapid development of wind power industry. Especially, with the rapid increase of the wind turbine unit capacity, more and more factors need to be taken into consideration for the design and manufacture of large-scale wind turbine gearbox. In this paper, megawatt-level wind turbine gearbox is considered as the research object.Various structural optimization methods are applied to study the wind turbine gearbox when its original performance is guaranteed. The main contents are as follows:(1) Static and dynamic analysis of wind turbine gearbox. Simplified models of the wind turbine gearbox components are established and then assembled in the3D graphics software SolidWorks according to the structural characteristics. In addition, the reasonable boundary conditions and loads for finite element analysis are determined. Then the simplified models are imported into CAE software HyperWorks and Workbench to finish the work of geometry cleanup, static analysis and modal analysis. Finally, analysis results including displacement field, stress field, natural frequencies and vibration modes of the gearbox and input stage planet carrier under limit load condition are obtained.(2) Structural lightweight of wind turbine gearbox. Not only size optimization, shape optimization and topography optimization are applied to the wind turbine gearbox, but also topology optimization and size optimization are applied to the input stage planet carrier. According to the analysis results and design goal, different kinds of variables are determined to finish different optimization designs. In addition, for the consideration of optimization design, all structural optimizations are carried out under the limit load condition.(3) Structural optimization based on support vector machine. Relevant theory knowledge about support vector machine and fruit fly optimization algorithm which is newborn in the field of optimization algorithm is introduced. Then, programme in MATLAB to model and optimize using the sample datas generated in size optimization of the gearbox and planet carrier. As the results show, support vector machine has a strong generalization ability; fruit fly optimization algorithm has a quick optimization speed and can quickly find the global optimal solution.(4) Analysis and comparison between the original model and the optimized model. According to the structural optimization results, wind turbine gearbox and input stage planet carrier are remodeled and reanalyzed. Then static analysis and modal analysis which are compared with the original ones are carried out for wind turbine gearbox. In addition, calculation of parallelism values is applied to wind turbine gearbox and input stage planet carrier, and compare them with the original ones.In summary, the optimized wind turbine gearbox and input stage planet carrier ensure the performance of the original structure. What’s more, the total quality decreases substantially by3.67%, which is about666.7kg, achieving the goal of lightweight.