自激式振动深松机设计及试验研究

发布时间：2018-10-23 20:35

【摘要】：土壤深松的目的是为了打破硬且厚的犁底层结构,在机器深松过程中,耕作阻力大消耗大量的能源,深松费用高。在满足农业生产对土壤加工要求的前提下,减少土壤耕作阻力、降低能源消耗,是国内外农机研究工作者十分关注的问题。本论文结合国家自然科学基金项目“自激振动深松部件碎土机理与减阻优化”(项目编号：51175354)开展研究。为了寻求土壤深松机具设计理论依据,探讨了深松机具结构参数和工作参数对工作阻力的影响。本研究采用理论分析与试验研究相结合的方法,通过深松铲土槽试验,研究振动深松部件对牵引阻力的影响；通过对深松机具深松过程的动态响应特性研究,分析振动耕作部件与土壤相互作用规律、土壤破碎机理、振动部件振动机理,揭示振动深松部件的振动产生原因及振动规律。通过和深松部件切削土壤过程的模拟仿真,分析以牵引阻力为目标的深松机具的最佳结构参数,为自激式振动深松机的设计提供理论依据,进而研制自激式振动深松机。通过样机田间试验,检测所设计深松机的深松性能及工业要求是否满足需要。通过对田间试验得到的加速度和牵引阻力数据处理,研究深松机系统的动态特性,以及振动部件的振动特性。本研究以自激式振动深松机为研究对象,以牵引阻力最低为目标,借助动力学分析、试验研究、数值模拟技术相结合的方法开展研究。主要研究成果如下：(1)分析土壤的动力性质,通过三轴压缩试验及其数值模拟,研究土壤的剪切性质。研究表明,土壤间相对移动产生摩擦力,使土壤间产生剪切力,当土壤的剪切力达到土壤的失效应力时,土壤发生破碎。对振动耕作部件的减阻过程分析可知,振动部件牵引力小,碎土效果好。(2)对弹齿式深松铲和刚性深松铲进行土槽试验研究。作业工程相同时,与刚性深松铲相比,弹齿式深松铲牵引阻力减小9.95%,深松比阻减小了14.52%,有较好的深松减阻效果。进行正交试验的极差分析和方差分析综合分析,讨论铲柄类型、前进速度、耕深对牵引阻力、功耗、比阻的影响。试验结果表明：当选用弹齿式深松铲、前进速度为1m/s、耕深为20cm时,牵引阻力、功耗、深松比阻均出现最小值,表明弹齿式深松铲更适用的耕深为20cm。由深松铲的振动分析可知,弹齿式深松铲的振动主频率为5.86Hz,刚性深松铲的振动主频率为4.39Hz。地表不平和土质不均匀等低频成分导致土壤阻力不断变化,进而引起弹齿式深松铲的振动。(3)应用LS-DYNA显示动力学分析程序,进行深松部件与土壤相互作用的有限元分析分析深松铲对土壤的作用过程,以及土壤的破碎过程,比较两种深松铲土壤的抛土轨迹。结果表明,弹齿式的最大应力发生在S型铲柄的第一个弯曲处,土壤扰动范围大。(4)自激式振动深松机的研制。通过对分层深松机工作过程的数值模拟,以牵引阻力最小为试验指标,前进速度V,前后铲耕深差H,前后铲间距L,进行正交旋转组合试验,建立回归方程,应用MATLAB求出最优解。试验结果表明：当前进速度V=1.06m/s,前后铲耕深差H=95mm,前后铲间距L=402mm,牵引阻力达到最小值F=4.2kN。根据最优的工作参数,对分层深松机构的工作过程进行仿真,研究分层深松机构深松减阻机理。(5)对设计样机进行田间试验。对土壤的物理参数进行测量,结果表明在地表下30cm处土壤坚实度达到最大值。深松机性能试验结果分析表明：深松机工作稳定,入土行程较短,为2.2m。平均松土深度为30.2cm,松土深度稳定性系数为97.9%。(6)自激式振动深松机系统动态响应特性分析。对田间试验得到的振动加速度和牵引阻力数据进行分析,通过预处理得到振动加速度与牵引阻力时域曲线,弹齿式深松铲的振动属于复杂的周期振动。在前进速度1m/s、耕深为0.3m时,与非振动下的牵引阻力相比,振动下的牵引阻力牵引阻力均值平均减少11.31%,具有明显的减阻效果。对振动加速度和牵引阻力信号进行频域分析。深松机振动的主频率为6.84Hz,振动周期为0.15s。弹齿式深松铲和弹簧的振动是引起整机振动的两个主要原因。对深松机振动系统求取传递函数,应用Routh(劳斯)稳定判据和Bode稳定判据,可知深松机振动系统稳定。
[Abstract]:The purpose of the soil deep loosening is to break the hard and thick plough bottom structure. In the process of deep loosening of the machine, large amount of energy is consumed during the deep loosening of the machine, and the deep loosening cost is high. Under the premise of meeting the requirements of agricultural production on soil processing, reducing soil tillage resistance and reducing energy consumption is a matter of great concern to agricultural machinery research workers at home and abroad. This thesis is combined with the National Natural Science Foundation of China. Mechanism and Drag Reduction Optimization of "Self-excited Vibration Deep Loose Parts" (Item number: 51175354). In order to find the theoretical basis of soil deep loosening tool design, the influence of structure parameters and working parameters on working resistance is discussed. According to the method of theoretical analysis and experimental research, the influence of vibration deep loose parts on traction resistance is studied by soil-soil groove test of deep soil, and the interaction law of vibrating farming parts and soil is analyzed by dynamic response characteristic of deep loosening process of deep loosening tool. The mechanism of soil crushing and the mechanism of vibration component vibration are used to reveal the reason and vibration rule of vibration of vibration-deep loose parts. Through the simulation of the process of cutting the soil through the deep loosening part, the optimum structural parameters of the deep loosening tool with the traction resistance as the target are analyzed, and the theoretical basis is provided for the design of the self-excited vibration deep loosening machine, and the self-excited vibration deep loosening machine is further developed. Through the field experiment of the prototype, it is tested whether the deep loosening performance and the industrial requirements of the designed deep loosening machine meet the needs. The dynamic characteristics and vibration characteristics of the vibration component were studied by data processing of acceleration and traction resistance obtained from field experiments. In this study, the self-excited vibration deep loosening machine was used as the research object, with the lowest traction resistance as the target, and the research was carried out by means of dynamic analysis, experimental research and numerical simulation technology. The main research results are as follows: (1) The dynamic properties of soil are analyzed, and the shear properties of soil are studied by triaxial compression test and numerical simulation. The results show that the relative movement of soil generates friction force, which causes shear force among the soil, and when the shear force of soil reaches the soil's failure stress, the soil is broken. It can be seen from the analysis of drag reduction process of vibrating tillage parts, that the traction of the vibrating part is small and the soil breaking effect is good. (2) To study the soil groove test of the elastic tooth type deep loosening shovel and the rigid deep loosening shovel. Compared with the rigid deep loosening shovel, the drag resistance of the elastic tooth type deep loosening shovel is reduced by 9.95% compared with the rigid deep loosening shovel, and the deep loosening ratio resistance is reduced by 14.52% compared with the rigid deep loosening shovel, and the deep loosening drag reducing effect is good. The difference analysis of orthogonal test and analysis of variance analysis were carried out to discuss the effect of shovel handle type, advancing speed, ploughing depth on traction resistance, power consumption and specific resistance. The experimental results show that the minimum value of drag resistance, power consumption and deep loosening ratio of the spring tooth type deep loose shovel is 1m/ s and 20cm depth, which indicates that the depth of ploughing is 20cm more suitable for the elastic tooth type deep loosening shovel. According to the vibration analysis of the deep loosening shovel, the vibration main frequency of the elastic tooth type deep loosening shovel is 5.86Hz, and the vibration main frequency of the rigid deep loosening shovel is 4.39Hz. Low frequency components, such as uneven surface roughness and uneven soil texture, have caused the soil resistance to change continuously, and then the vibration of the elastic tooth type deep loosening shovel is caused. (3) Using LS-DYNA display dynamics analysis program, finite element analysis of soil interaction between deep soil and soil was carried out. The results show that the maximum stress of the elastic tooth type occurs at the first bend of the S-shaped shovel, and the soil disturbance range is large. (4) Development of self-excited vibration deep loosening machine. Through the numerical simulation of the working process of the layered deep loosening machine, the optimal solution is obtained by using MATLAB to establish the regression equation with the minimum drag resistance as the test index, the forward speed V, the front and rear shoveling depth difference H, the front and rear shovel distance L, and the orthogonal rotation combination test. The results show that when the forward speed V = 1. 06m/ s, the depth difference of the front and rear shovels is H = 95mm, the distance L of the front and back shovel is L = 402mm, and the traction resistance reaches the minimum value F = 4.2kN. According to the optimum operating parameters, the working process of the layered deep loosening mechanism is simulated, and the mechanism of deep loosening and drag reduction of the layered deep loosening mechanism is studied. (5) performing field test on the design prototype. The physical parameters of the soil were measured, and the results showed that the soil firmness reached the maximum at 30cm below the surface. The results show that the operation of the deep loosening machine is stable, the stroke is short, and it is 2.2m. The average depth was 30. 2cm and the depth stability coefficient was 97. 9%. (6) Dynamic response characteristic analysis of self-excited vibration deep loosening system. The vibration acceleration and traction resistance data obtained in the field experiment are analyzed, and the vibration acceleration and drag resistance time domain curve are obtained by pre-processing, and the vibration of the elastic tooth type deep loosening shovel belongs to complex periodic vibration. When the advancing speed is 1m/ s and the ploughing depth is 0. 3m, the average reduction of traction resistance traction resistance under vibration is 11.31% compared with the traction resistance under non-vibration, and has obvious drag reduction effect. Frequency domain analysis of vibration acceleration and traction resistance signal is carried out. The main frequency of the vibration of the deep loosening machine is 6.84Hz and the vibration period is 0. 15s. The vibration of the elastic tooth type deep loosening shovel and spring is the main cause of the vibration of the whole machine. In order to obtain the transfer function for the vibration system of the deep loosening machine, the Routh stability criterion and the Bode stability criterion are applied to know the stability of the vibration system of the deep loosening machine.
【学位授予单位】：沈阳农业大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：S222

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