振动式土壤切削系统的振动频率范围研究

Research on the vibration frequency range of vibratory soil cutting system

本研究基于共振效应分析,探索了振动式土壤切削机具振动参数,特别是振动频率的选取方法,为相关机具开发提供参考。在测得室内土槽土壤固有振动参数基础上,以单自由度振动系统共振效应分析为切入点,通过经验值、半功率带宽、振幅放大因子和正态分布等四种方法计算土壤共振区参数,分析了振动式土壤切削机具的振荡频率选择范围和原则。测得第一阶土壤固有振动频率f_(0)为29.688 Hz,对应阻尼比ζ为0.142。由工程经验法、放大因子等于2和正态分布1σ所确定的共振区间(约为0.75 f_(0)~1.25 f_(0)),对于振动式土壤切削机具振动频率选择而言是有效的,但略窄。放大因子等于1确定的土壤共振区间最宽(0~1.414 f_(0)),机具振动参数选择范围也最宽,而振动减阻效果可能会略差。推荐用正态分布2σ下限频率0.470 f_(0)或者正态分布3σ下限频率0.205 f_(0),而采用正态分布1σ上限频率1.265 f_(0)作为机具振荡频率的选择范围,理论上可获得较好的土壤振动切削减阻效果和较宽的土壤参数适应能力。

The study,based on the analysis of resonance effect,explored the selection method of vibration parameters,especially the vibration frequency,for the development of related tools.The single-degree-of-freedom vibration model of cut soil was used as the starting point after measuring soil natural vibration parameters in the soil bin.Four methods,including empirical value,half-power bandwidth,amplitude amplification factor,and normal distribution,were used to calculate and analyze the soil resonance interval frequency bandwidth and principle.The first-order soil natural vibration frequency f_(0)was measured to be 29.688 Hz,and the corresponding damping ratioζwas 0.142.The resonance frequency bandwidth(approximately 0.75 f_(0)-1.25 f_(0))was determined by the empirical method and by setting the amplification factor to 2 and the normal distribution to 1σ.The bandwidth was effective for the vibratory soil cutting machine,but it was slightly narrow.The soil resonance frequency bandwidth determined by setting the amplification factor to 1 was the widest(0-1.414 f_(0)),and the selection range of machine vibration parameters was also the widest,but the vibration drag reduction effect may be slightly worse.It was recommended to use the lower limit frequency 0.470 f_(0)with normal distribution 2σ,or the lower limit frequency 0.205 f_(0)with normal distribution 3σ,and use the upper limit frequency 1.265 f_(0)with normal distribution 1σas the selection range of the machine oscillation frequency.Theoretically,a better resistance reduction effect and wider soil parameter adaptability of vibration soil cutting system can be obtained.