旋耕刀结构优化设计与动力稳定性分析
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摘要
为了解决土壤和草根对旋耕刀的阻力和刀尖受到的摩擦力及振动冲击而造成的疲劳失效问题,利用有限元软件对旋转对称六刀刃旋耕刀进行了强度评价并对其结构进行了5次优化改进,并分别对5种优化改进结构建立了数值模型,且进行了静态和模态数值分析。静态强度分析结果表明:随着旋耕刀结构的优化改进,其最大应力集中和最大变形量明显减小。动力学分析结果表明:第3次优化改进后的3种弧形旋耕刀各阶固有频率都提高于100Hz并避开了工作频率。最后,通过对比分析5种优化改进结构的强度、固有频率、振型和动力稳定性等提出了飞轮性旋转对称弧形刀刃圆角旋耕刀。该旋耕刀的特点是,应力和变形量比改进前的分别降低2倍和4倍以上,第1阶固有频率由改进前的12Hz提高到170Hz。新提出的旋耕刀型应力集中很小、固有频率很高,具有可提高疲劳寿命、耐磨性好与使用寿命长等特点,是旋耕机上最适合用的刀片之一。如果不考虑偏心率的影响,在工作频率范围内弧形旋耕刀不会出现振动和共振现象。
In order to solve the problem of soil and root friction fatigue and vibration impact on the rotary blade and tip resistance is caused by the failure,this paper of rotationally symmetric six blade rotary blade of strength evaluation and its structure was optimized and improved and then 5 times respectively on five optimization improvement structure established numerical model,the numerical analysis of static and modal using finite element software. The analysis results show that static strength,with the optimization of rotary blade structure improvement and the maximum stress concentration and the maximum deflection decreases obviously. Dynamic analysis results also indicate that the third optimization of 3arc rotary blade improved each order natural frequency are increased in the 100 Hz and split the work frequency. Finally,through the comparative analysis of five kinds of optimization proposed flywheel rotation symmetric arc- shaped blade fillet rotary blade improved structure strength,natural frequency,vibration mode and dynamic stability. The characteristics of the rotary blade,stress and deformation than the improved reduced respectively2 times and 4 times above,the first order natural frequency than the previous algorithm improved from 12 Hz to 170 Hz. Rotary blade type new stress concentration is very small,the natural frequency is very high,so it can improve the characteristics of fatigue life of good wear resistance and long service life,one of the most suitable blade rotary cultivator for. If we do not consider the influence of eccentricity,in the working frequency range of arc rotary blade vibration and the resonance phenomenon does not appear.
In order to solve the problem of soil and root friction fatigue and vibration impact on the rotary blade and tip resistance is caused by the failure,this paper of rotationally symmetric six blade rotary blade of strength evaluation and its structure was optimized and improved and then 5 times respectively on five optimization improvement structure established numerical model,the numerical analysis of static and modal using finite element software. The analysis results show that static strength,with the optimization of rotary blade structure improvement and the maximum stress concentration and the maximum deflection decreases obviously. Dynamic analysis results also indicate that the third optimization of 3arc rotary blade improved each order natural frequency are increased in the 100 Hz and split the work frequency. Finally,through the comparative analysis of five kinds of optimization proposed flywheel rotation symmetric arc- shaped blade fillet rotary blade improved structure strength,natural frequency,vibration mode and dynamic stability. The characteristics of the rotary blade,stress and deformation than the improved reduced respectively2 times and 4 times above,the first order natural frequency than the previous algorithm improved from 12 Hz to 170 Hz. Rotary blade type new stress concentration is very small,the natural frequency is very high,so it can improve the characteristics of fatigue life of good wear resistance and long service life,one of the most suitable blade rotary cultivator for. If we do not consider the influence of eccentricity,in the working frequency range of arc rotary blade vibration and the resonance phenomenon does not appear.
引文
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[10]刘芳,叶进.微耕机与现代设计方法[J].农机化研究,2013,35(5):246-248.
[11]赵少汴,王忠保.抗疲劳设计[M].北京:机械工业出版社,1997:65-80.
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[14]王洪亮,张瑞宏.基于NXNASTRAN的旋耕刀轴结构与疲劳分析木[J].中国农机化学报,2013,34(3):135-138.
[15]濮良贵,纪名刚.机械设计[M].北京:高等教育出版社,2010:210-212.
[16]范钦珊,唐静静.工程力学[M].北京:高等教育出版社,2007:59-62.
[17]中国农业机械化科学研究院.农业机械设计手册[K].北京:中国农业科学技术出版社,2007:150-170.
[2]张欣悦,李连豪.1GSZ--350型灭茬旋耕机联合整地机的设计与实验叨[J].农业工程学报,2009,25(5):73-77.
[3]赵伟,张文春.深松旋耕组合作业机的研制与试验研究[J].农业工程学报,2007,23(1):125-128.
[4]闰国琦,张铁民.我国微耕机技术现状与发展趋势[J].安徽农业科学,2008,36(25):37-39.
[5]Yong RN,Hanna A W.Finite element analysis of plane soil cutting[J].Of Terramechanic,1977,14(3):103-125.
[6]Chi L,Kushwaha R L.Finite element analysis of forces on a plane soil blade[J].Can.Agric.Eng,1989,31(2):135-140.
[7]郭志军,周志立,佟金,等.抛物线型切削面刀具切削性能二维有限元分析[J].洛阳工学院学报,2002,23(4):1-4.
[8]郭志军,孙政伟,张毅,等.推土铲切削性能的二维有限元分析[J].拖拉机与农用运输车,2006,33(6):29-33.
[9]张柯柯,卢剑锋,张富贵,等.微耕机的结构设计与动力学分析[J].农机化研究,2012,34(4):58-60.
[10]刘芳,叶进.微耕机与现代设计方法[J].农机化研究,2013,35(5):246-248.
[11]赵少汴,王忠保.抗疲劳设计[M].北京:机械工业出版社,1997:65-80.
[12]高烨.多轴疲劳研究阴[J].机械强度,1996,18(1):9-13.
[13]黄虎,王晓燕.固定道保护性耕作节能效果试验研究[J].农业工程学报,2007,23(12):140-143.
[14]王洪亮,张瑞宏.基于NXNASTRAN的旋耕刀轴结构与疲劳分析木[J].中国农机化学报,2013,34(3):135-138.
[15]濮良贵,纪名刚.机械设计[M].北京:高等教育出版社,2010:210-212.
[16]范钦珊,唐静静.工程力学[M].北京:高等教育出版社,2007:59-62.
[17]中国农业机械化科学研究院.农业机械设计手册[K].北京:中国农业科学技术出版社,2007:150-170.