履带式玉米收获机底盘车架振动特性分析与优化OA

[Objective]In the process of full mechanization of corn production,the mechanical harvesting lags relatively behind,especially regarding the research on the dynamic characteristics of tracked harvesters'chassis,which remains a blank.Aiming at the critical problems of severe vibration and susceptibility to resonance in the chassis frame of tracked corn harvesters during complex farmland operations,conducting vibration characteristic analysis and structural optimization research is beneficial to en-hancing the operation smoothness and reliability of the entire machine,improving harvesting quality,reducing grain loss,and providing a theoretical basis for chassis lightweight design and fatigue life assessment,ultimately promoting the technological upgrading of corn harvesting machinery and the sustainable development of the industry in China.[Methods]A high-precision fi-nite element model of the frame was constructed within the ANSYS Workbench environment.By means of the free modal anal-ysis methods,the first four natural frequencies and vibration modes were obtained(the first four orders were 10.965,12.703,15.243,and 21.792 Hz,respectively),and the effectiveness of the model was verified using the hammer impact modal test.Based on the aforementioned model,static simulations under two extreme load conditions,field obstacle-crossing and full-load bending,were further carried out to evaluate its structural response.To achieve a fundamental improvement in vibration perfor-mance,sensitivity analysis was innovatively introduced.Nine variables with high sensitivity to modal frequency were screened from 16 structural size parameters,and a multi-objective genetic algorithm was further applied to optimize the design of the key size parameters of the frame.[Results]The optimization results showed that the first four natural frequencies of the frame signifi-cantly increased to 12.703,21.792,27.100,and 38.972 Hz,effectively avoiding the excitation frequency range of main work-ing components such as the threshing drum and engine;the first four orders of modal frequencies increased by 15.85%,42.96%,8.19%,and 8.87%,respectively,compared to before optimization,fundamentally reducing the risk of resonance.[Conclusion]This article focused specifically on the special chassis of the"tracked type".It solved the problem of vibration avoidance design for multivariable complex frames through sensitivity analysis,and its optimization process had engineering pro-motion value for low-cost vibration reduction of similar agricultural equipment.However,the optimization scheme proposed in this study only took wall thickness as the design variable and did not change the existing assembly relationship.In the future,it can significantly improve the low-order natural frequencies while controlling the structural weight gain within a reasonable range.