摘要
采棉机在工作时,会因载荷激励而导致机架振动,当激励频率在机架固有频率范围内,会产生共振现象,对采棉机产生影响.为提高采棉机工作性能,对采棉机机架进行模态分析,得到机架前6阶模态参数,通过分析振源激励特性,发现机架一阶和四阶模态频率处在振源激励区间,将其与机架质量设为优化目标,机架各尺寸设定为设计变量;对机架进行灵敏度分析,基于CCD抽样设计并运用Kriging方法拟合响应面,运用多目标遗传算法得到5个优化方案,结合熵权法与线性加权法,其中方案1综合得分最高是最佳设计方案.优化后机架一阶模态频率97 Hz降低到91 Hz,四阶模态频率225 Hz增加到230 Hz,远离发动机激振频率100 Hz和220 Hz;质量为688.8 kg降低1.5％.经静力学与谐响应分析验证,优化后的机架满足工作要求.
Abstract
When the cotton picker is working,the frame vibration will be caused by the load excitation.When the excitation frequency is within the natural frequency range of the frame,the resonance phenomenon will occur,which will affect the cotton picker.In order to improve the working performance of the cotton picker,this paper conducts modal analysis on the frame of the cotton picker and obtains the first six modal parameters of the frame.By analyzing the excitation characteristics of the vibration source,it is found that the first and third modal frequencies of the frame are in the excitation interval of the vibration source,and the frame quality is set as the optimization target,and the dimensions of the frame are set as design variables.The sensitivity analysis of the rack is carried out based on CCD sampling design and Kriging method is used to fit the response surface.Five optimization schemes are obtained by using multi-objective genetic algorithm.Combining entropy weight method and linear weighting method,scheme 1 has the highest comprehensive score and is the best design scheme.After optimization,the first-order mode frequency of the rack is reduced from 97 Hz to 91 Hz,the fourth-order mode frequency is increased from 225 Hz to 230 Hz,and the excitation frequency away from the engine is 100 Hz and 220 Hz.The mass is 688.8 kg reduced by 1.5％.It is verified by statics and harmonic response analysis that the optimized frame meets the working requirements.
基金项目
新疆生产建设兵团重点领域创新团队建设计划(2019CB006)
国家科技期刊平台
NSTL
万方数据