| Modal analysis theory,this paper based on a single degree of freedom for the porosity of the soil,com pactness and moisture content of single factor experiment,to explore the relationship between the soil poro sity,compactness and moisture content,soil compaction machinery and use homemade tillage soil natural f requency and soil porosity,explore the relationship between the compactness and moisture content.The ver tical acceleration,longitudinal acceleration,vertical vibration frequency and longitudinal vibration frequen cy of the front axle,rear axle and seat of the tractor under three working conditions were analyzed.Throug h a large number of experimental analysis,the following conclusions are obtained:1.To explore the cultivation of soil moisture content to its porosity,and the influence of compactne ss and the relationship between porosity and compactness: when making bread soil samples at the same hei ght,density increased with the increase of soil moisture content in the soil sample increased,in close to the moisture content of 12% or so,soil compaction appears after the maximum began to decrease;With the inc rease of soil moisture content,the porosity of soil samples began to decrease regularly.However,when the soil moisture content reached about 11%,the trend of decrease tended to be gradual.There is a negative cor relation between soil compactness and soil porosity when the water content range is 3%-15%,and the corre lation is extremely significant.2.The relationship between soil moisture content,soil porosity,soil compactness and soil natural fr equency was obtained through the modal analysis of soil through hammer test.On the whole,the soil natur al frequency increases with the increase of water content,and the higher the soil porosity is,the more obvio us the change with water content is.The overall variation rule of soil natural frequency with soil porosity is that the soil natural frequency first increases with the increase of porosity,then presents a gentle trend and t hen continues to increase,and the higher the water content is,the faster the gentle trend appears.With the i ncrease of soil compactness,the natural frequency of soil first decreases,and then continues to decrease aft er a gentle trend appears.Moreover,the higher the soil moisture content is,the smaller the gentle trend is,a nd the greater the degree of compactness decreases.3.The harvested cotton field is taken as the test site,and John Deere 5E-854 model tractor is taken as the research object.The tractor can be concluded that(1)the vertical acceleration of the front bridge of th e tractor is greater than the longitudinal acceleration.(2)The longitudinal acceleration of the rear axle of the tractor is greater than the vertical acceleration,and in the course of the test ground,the vertical vibration ha s two vibration frequency bands,the longitudinal vibration has two vibration frequency bands.(3)The vertic al acceleration of the seat of the tractor is greater than the longitudinal acceleration,and in the test ground r unning process,the vertical vibration has two vibration frequency bands,the longitudinal vibration has two vibration frequency bands.(4)After harvest of cotton as the experimental site,John Deere 5E-854 type tra ctor as the research object,the tractor to shut down the power,in the case of drag,tractor front tire pressure is 200 Kpa,no obvious vibration frequency,the tractor front axle vertical tractor front tire pressure of morethan 200 Kpa,the vertical vibration frequency of 0-8Hz.The longitudinal vibration frequency of the front axle,the vertical and longitudinal vibration frequency of the rear axle and the vertical and longitudinal vibr ation frequency band of the seat are all 0-10 Hz.The results of this experiment can provide reference and theoretical basis for the research on the vibration a nd noise reduction of agricultural tractors and the passing performance of tractors after the operation of diff erent agricultural machinery and tools. |
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