曲翼中耕培土装置作业参数优化与试验

中耕培土作业质量对防旱保墒、促进玉米植株生长有重要影响,合理的结构及作业参数可有效改善玉米的生长环境.针对传统中耕培土器碎土率较低、培土高度不佳的问题,该研究对曲翼中耕培土装置(以下简称曲翼培土装置)曲翼结构及其关键作业参数进行优化.首先对阻力监测系统进行改进并通过土槽试验对其可靠性进行验证;再基于装置关键部件与结构理...     

Overload-controlled cultivation shanks under static loads

Cultivators for stony soils have to be protected to prevent breakage. Draft forces of cultivator shanks in hard clod-forming soils are higher than in the temperate soils of wet areas. Load-control devices are used to prevent breakage, but most of them cannot maintain constant depth in hard soils.

Load-controlled light cultivator shanks and chisel plows were tested to define their behaviour under high soil resistances and obstacles. The shanks were loaded with horizontal forces to simulate soil resistances as found in cultivating hard clod-forming soils.

The variations in the depth, the lift angle and the backward deflection were measured. The maximum stresses on the shanks were calculated.

It was found that only the light cultivator shank with a pre-loaded special design moment control device can till hard soils with small reasonable depth variations and still run over an obstacle without being broken.

Only the heavy chisel plow with the rear spring load control device can run over an obstacle without being broken, but it loses cultivation depth under too low a soil resistance, compared with the maximum draft that it can hold.     

Performance of low-draft tillage implements on a hard setting Alfisol of the SAT in India

Abstract. Four bullock-drawn tillage implements (mouldboard plough, chisel plough, sweeps, and shovels) were evaluated on a hard-setting Alfisol. Measurements included draft requirement, bulk density, cone index, soil crust strength, water content of the plough-layer and crop yield. Changes in bulk density and cone index due to tillage decreased with time and were negligible by the end of the growing season. After tillage with a mouldboard plough the crust was stronger than after tillage with other implements. The shovel cultivator enabled the soil to store more water, and required least draft per unit effective area of cut.     

驱动式碎土除草多功能马铃薯中耕机设计与试验

针对传统锄铲式中耕机在土壤黏重板结情况下碎土率和除草率低、培土效果不佳等问题,该文设计了集深松碎土、铲除杂草、侧深施肥、培土起垄等多功能于一体的驱动式马铃薯中耕机,并对机具关键部件进行设计与分析,确定了深松铲、碎土刀、培土器的结构以及工作参数,在设计分析的基础上进行田间试验,并与锄铲式中耕机进行对照试验。田间试验表明:本文所研制的驱动式中耕机碎土率为95.1%、除草率为96.3%、伤苗率为1.2%、土壤蓬松度达到21.5%、油耗为13.2 kg/hm^2,满足相关标准作业指标要求。对照试验表明:相较于传统锄铲式中耕机,驱动式马铃薯中耕机碎土率提高3.3个百分点、除草率提高3.1个百分点、伤苗率降低1.6个百分点、土壤蓬松度提高2.7个百分点、油耗降低28%,明显优于其作业效果,满足国家标准碎土率≥85%、伤苗率≤5%、除草率≥90%的要求。     

仿生减阻树木移植机铲片设计与试验

铲片是树木移植机的重要工作部件,其尺寸参数、形状以及数量分布决定着移植机的挖土性能和整机的能耗大小。为了有效减小铲片切削土壤时所受阻力、减小整机能耗,该文根据树木移植机的工作状况和特点,对铲片进受力分析并建立力学模型。仿照土壤动物步甲的掘土器官大颚的体表结构设计非光滑仿生铲片,运用动力学分析软件ANSYS/LS-DYNA对原型铲片和仿生铲片切削土壤过程进行数值优化,通过原型铲片的数值仿真确定最佳铲片切削角为83?,在相同的铲片结构和土壤条件下,数值优化得到仿生铲片最佳参数为表面凸起直径14 mm,凸起中心距28 mm,凸起高度4 mm。根据最佳参数研制仿生铲片,并安装在移树机上进行原型铲片和仿生铲片的作业对比试验,发现仿生铲片有效减阻11.11%,证明了仿生非光滑铲片具有较好的减阻特性,可为整机节能降耗奠定基础。     

铲齿-双滚筒组合式花生捡拾装置研制

两段收获是国内花生机械化收获主要方式。大中型花生捡拾收获机所配置的弹齿滚筒式捡拾装置结构复杂且易损坏,捡拾过程中不仅存在植株抛起、壅堆、漏捡和掉果等问题,弹齿弹出地面时也会造成扬尘,严重制约了花生收获作业效率、增加花生损失,加剧环境污染。针对上述问题,该研究在分析弹齿滚筒捡拾花生过程基础上,提出了由铲齿、拨秧滚和捡拾滚（简称双滚筒）构成的花生捡拾机构,研制出相应的捡拾装置样机并进行田间性能试验;基于Box-Behnken中心组合设计原理,以植株捡拾率和荚果落果率为试验指标、以机组前进速度、捡拾速比和铲齿半径为试验因素进行了正交试验,并对试验因素进行优化。试验结果表明,铲齿-双滚筒组合式花生捡拾装置作业中不存在植株抛起、壅堆和弹齿扬尘等问题;在田间试验条件下,作业速度为1.2 m/s、捡拾速比为1.2、铲齿半径为498 mm时,花生植株捡拾率高于99.22%,落果率低于1.84%,均优于花生捡拾作业标准要求。铲齿-双滚筒研究结果对解决国内花生捡拾收获机存在的捡拾问题具有重要意义。     

Influence of soil strength on root growth: experiments and analysis using a critical-state model

Roots grow thicker in compacted soil, even though it requires greater force for a large object to penetrate soil than it does for a small one. We examined the advantage of thickening in terms of the stresses around a root penetrating with constant shape, rather than the stresses around an expanding cylinder or sphere, as has been studied previously. We combined experiments and simulations of the stresses around roots growing in compacted soils. We measured the diameter of pea roots growing in sandy loam and clay loam at four different densities, and the critical‐state properties of the soils. At a penetration resistance of about 1 MPa the diameter of the roots in the sandy loam was about 40% greater than that at 0.7 MPa, and at 2 MPa it was about 60% greater. In the clay loam, there was less thickening – about 10% greater at 1 MPa and about 20% greater at 1.5 MPa. The maximum axial stresses were predicted using a critical‐state finite‐element model to be at the very tip of the root cap. When there was friction between the root and the soil, shear stresses were predicted with smaller values at the tip than just behind the tip. When the interface between the soil and the root was assumed to be frictionless, there were by definition no shear stresses. In the frictionless case the advantage of root thickening on relieving peak stress at the root tip was diminished. The axial and shear stresses were predicted to be smaller in the clay loam than in the sandy loam and may explain why the roots did not thicken in this soil although its resistance to penetration was similar. Our results suggest that the local values of axial and shear stresses experienced by the root near its tip may be as important in constraining root growth as the total penetration resistance.     

基于灭茬圆盘驱动旋耕刀多功能耕整机设计与试验

针对玉米作物根茬难清除、制约后续标准作业的问题,结合北方寒地保护性耕作工艺,设计了一种与大马力拖拉机配套的茬地耕整机。该机采用联合作业方式,能够一次完成起茬、破茬碎土、垄体深松、灭茬旋耕、起垄、垄体整形等多项作业。设计了自驱动式弧形齿盘破茬器和螺旋碎土装置,破茬器转速为33～37r/min,旋耕刀转速为350～390r/min,深松深度为30cm左右。田间试验表明,该机工作性能良好,灭茬旋耕效果显著。与传统耕作机具和进口联合整地机相比,破土率提高2.4%～6.9%,破茬率提高6.3%～12.9%,节省油耗26.3%～40.4%。     

马铃薯专用中耕培土犁的应用及增产效果

中耕培土是马铃薯生产的关键耕作技术,影响马铃薯的产量和品质。传统的中耕培土犁培土效果达不到当前生产作业要求,限制了马铃薯产业发展。为解决该问题,该研究根据马铃薯生产现状,应用自主研发马铃薯专用中耕培土犁,并以传统中耕培土犁为对照,开展不同垄距培土犁培土效果对比试验,设置垄距为65、70、80和90 cm,分别在马铃薯苗期及现蕾期进行2次培土,探讨马铃薯专用培土犁的最佳培土模式。研究结果表明:应用马铃薯专用中耕培土犁培土,垄体明显增大,垄体土壤质量高于对照21.7%~33.4%,有利于马铃薯生育期地下干物质的积累,提高马铃薯匍匐茎数;有利于地下薯块的增长,大、中薯块茎产量增加,小薯块茎所占比率有所减少;马铃薯产量两年平均为38 215.0~43 131.2 kg/hm~2,比对照提高1.1%~7.3%,商品薯产量为33 788.9~39 346.7 kg/hm~2,比对照提高4.1%~11.2%,青薯产量为670.7~834.3 kg/hm~2,比对照降低18.7%~28.8%;其中垄距为80 cm培土处理马铃薯产量最高、青薯产量最低,均值分别为43 131.2和670.7 kg/hm~2,为马铃薯专用中耕培犁的最佳培土模式。该研究可为马铃薯生产提供指导。     

挖掘收获多功能曲面铲的设计与试验

摘要：针对传统根茎类作物挖掘工作铲阻力大、顺土性差、集果效果不好的问题,设计了多功能曲面挖掘铲。为提高挖掘入土性能和去土效果,挖掘铲纵向平面采用犁铧与圆弧曲面两段组合设计;为提高横向流畅顺土性能和向中集果率,挖掘铲横向平面采用功能分段及样条曲线拟合设计。通过与应用较广的普通平面多边形挖掘铲的对比试验,表明多功能曲面铲去土率提高了4.8%,向中集果率提高了1.2%,掉果率降低了1.03%。但两者的挖掘阻力相差不大。该挖掘铲的设计为后续的夹持装置和去土装置的作业提供了参考。     

Wear of spring tine cultivator points in sandy loam and light clay soils in southern Poland

Correct evaluation and forecasting of durability of soil cutting parts are the decisive factors for proper operation of agricultural machinery. During operation of cultivators, over two-fold difference in wear of cultivator points is observed, which makes establishing of their exchange periods extremely difficult. So, there is a need to conduct some research aimed for determination of relationship between arrangement of the points in individual cultivator rows and their wear. The presented experiments were performed under authentic farm conditions during spring soil loosening and levelling operations before sowing and planting, in sandy loam and light clay soils. Changes in length and thickness of the spring tine points, wear patterns and weight loss were measured. Loss in length of spring tine points was described by a complex function of the distance travelled or by an exponential function of the distance from the measuring point to the symmetry axis of a spring tine point; loss in thickness was described by a linear function. It was found that soil type, as well as arrangement of the points in individual cultivator rows and their position in relation to the tractor wheel track, significantly influenced their wear. It was also observed that wear of spring tine points was 40–100% higher in the sandy loam soil than in the light clay soil, and that wear within a tractor wheel track was 17–40% higher than outside the track. Moreover, wear of points positioned in the first row on the cultivator frame was 26–100% higher than wear of those in the third row. The research results emphasise the need for field experiments at compare wear of spring tine points made of different materials or of different designs to take into account differences in wear due to positioning of the points on cultivator frames.     

侧深施肥直斜偏置式免耕播种开沟器设计与试验

采用侧深施肥技术,施肥铲作业后播种带两侧土壤高度不一致,易加剧播种机横向偏摆,进而导致播种深度均匀性和播种横向一致性较差。为解决上述问题,该研究设计了一种直斜偏置式免耕播种开沟器。该开沟器主要由切土斜刃、挡土定位板、偏置推土板等组成,作业时滑切土壤并将其推移至肥沟一侧拓宽种沟,避免种子落至肥沟后位置过深,提高播种质量。通过离散元仿真试验,以前进阻力、肥沟回土深度、种沟回土深度为试验指标进行二因素五水平正交旋转组合试验,得到斜刃滑切角为37°、偏置角为15°时开沟器作业性能最好。在最优参数下与双圆盘式、尖角式开沟器进行田间作业性能对比试验,相对于双圆盘式和尖角式开沟器,直斜偏置式开沟器播种深度变异系数分别降低41.12%、19.41%;播种横向变异系数分别降低39.00%、28.41%;前进阻力分别降低7.26%、28.20%;作业后肥沟与种沟回土深度分别提高9.47%、13.68%和33.33%、7.14%。试验结果表明,该开沟器可以减小前进阻力,增加肥沟与种沟回土,提高播种深度均匀性和播种横向一致性,可为播种开沟器的设计提供参考。     

温室用轻型方钢管柱脚底板压力及其简化计算模型

为研究半刚性柱脚底板压力分布,以轻型方钢管柱脚底板为研究对象,首先利用数值模拟方法,考虑柱脚与混凝土基础间非线性静力接触效应,针对4种加劲肋布置方式、6种偏心矩,分别计算24个轻型方钢管柱脚模型的底板受力情况,得到了底板压力分布规律,在此基础上提出了三折线底板压力分布模型,给出了轻型方钢管柱脚底板压力简化计算模型,并确定了相应关键参数。将简化计算模型结果与数值模拟、基于Winkler弹性地基梁模型的解析解和三角形压力分布的底板压力计算结果相对比。结果表明:三角形压力分布计算得到的底板最大压力值位于底板端部,而数值模拟、解析解及该文简化计算模型得到的最大压力值均位于柱截面翼缘处,且三角形压力分布的底板压力最大值明显大于该文简化计算模型结果,简化计算模型计算的底板压力最大值与数值模拟结果较为接近,且二者与解析解底板压力分布曲线亦吻合良好(误差大约为10%)。研究成果为轻型方钢管柱脚设计提供了更为精确适用的计算方法。     

不同边膜铲起膜性能分析及其起膜率对比试验

农田地膜污染治理中,由于秋后残膜回收中缺乏较为理想的机构起翻边膜,致使边膜埋于地表不易被回收部件进行回收,对土壤及环境造成一定的污染。为解决这一问题,选取目前较为普遍使用的2种边膜起膜机构开沟器和双翼铲,新设计一种单翼铲,对其进行力学分析,对比3种不同结构的边膜铲受力情况,并且在新疆库尔勒尉犁县开展田间对比试验,对比不同结构的边膜铲在田间的工作性能,考核起出残膜完整率、起膜率及有无壅土现象发生这3个关键因素。结果表明:边膜铲的受力大小与边膜铲入土角度和铲刃的长度有关,对3种边摸铲理论分析得出单翼铲的受力最大,开沟器受力最小,双翼铲受力较为合理,而在田间性能试验中虽然单翼铲受力最大但其作业效果最佳,起出边膜的完整率达100%、起膜率在95.4%、并且在作业中没有壅土现象发生,考虑到作业效果的突出,推荐单翼铲作为秋后残膜回收机的边膜起膜机构。研究结果可为秋后残膜回收机的边膜起膜机构的设计选择提供参考。     

An approach for draft prediction of combination tillage implements in sandy clay loam soil

A methodology to predict the draft requirements of combination tillage implements in any soil and operating conditions was developed. This methodology required the draft requirements of individual tillage implements in undisturbed soil condition and draft utilization ratio of the rear passive set of combination tillage implement, which is defined as the ratio of the drafts of the rear passive set operating in combination and individually. Laboratory experiments were conducted to measure the draft requirements of a reference tillage tool (single disk), three scale-model individual (moldboard plow, cultivator and disk gang) and two combination (moldboard plow with disk gang and cultivator with disk gang) tillage implements at different depths (5, 7.5 and 10 cm), speeds (1.2, 2.2, 3.2 and 4.2 km/h), wet bulk densities (in the range of 1.27–1.85 g/cm³) and cone index penetration resistance values (in the range of 445–1450 kPa) in soil bin filled with sandy clay loam soil. The average draft utilization ratio of the reference tillage tool obtained were analyzed by both orthogonal and multiple regression techniques to develop the regression equation considering soil properties, operating and tool parameters. The developed draft equation based on the above mentioned methodology was verified with the data obtained for the draft of scale-model and prototype combination tillage implements in the laboratory and field conditions, respectively. It was found that the developed equation predicted the draft of both combination tillage implements within an average absolute variation of 18.0 and 13.5%, respectively.     

Incorporation of triallate granules for wild oat control under dry conditions

Tests using various field implements (heavy duty cultivator, vibrashank cultivator, one-way discer, and the double disc or tandem disc) were conducted to determine if the incorporation implement affected wild oat (Avena fatua L.) control by triallate. All of the implements provided efficient control of wild oat by triallate granules, achieving up to 95% control of populations as compared to the untreated check plots. All incorporation treatments rendered triallate more effective compared to non-incorporated or surface only application. Under drought conditions the intensity of incorporation must be balanced against soil moisture losses resulting from the incorporation.     

Mathematical simulation and calculation of the soil compaction under dynamic loads

The deformation and compaction of loamy sandy soddy-podzolic soils under linear dynamic changes in the compressive stresses and in the course of the soil creeping were studied in field experiments. The rheological properties of these soils occurring in the viscoelastic state were described by a first-order differential equation relating the compressive stresses, the rates of their changes, and the velocities of the relative vertical compressive deformation. Regression equations were derived for the viscoelastic properties of the studied soil as functions of its density, moisture, and linear compaction velocity. Methods were proposed for the calculation of indices of the stress-strain state and the compaction of soils under specified conditions of changes in their compressive stresses with time and in the course of the soil creeping after the initial linear increase in load. Corresponding computer programs were developed. The effect of the main factors due to the linear increase in the compressive loads and in the course of the soil creeping on the rheological properties, the stress-strain state, and the density of soils was quantitatively estimated. The calculation showed that the values of the soil deformation and the density under compressive stresses lower than the ultimate strength were stabilized with time, and the properties of the viscoelastic soil approached elastic ones.     

拨指轮式马铃薯挖掘机试验

针对拨指轮式马铃薯挖掘机的明薯率和伤薯率相互牵制的问题,对它的工作性能进行正交试验研究。通过对试验结果的极差分析和方差分析,得出影响明薯率的因素主次为：拨指轮转速、铲轴与拨指轮轴之间的纵向距离、挖掘铲长度,影响伤薯率的因素主次为：拨指轮转速、挖掘铲长度、铲轴与拨指轮轴之间的纵向距离。考虑到试验因素对明薯率和伤薯率影响的大小和它们在挖掘机中所承担的任务,优化机具参数为：拨指轮转速为142 r/min、挖掘铲长度为480 mm、铲轴与拨指轮轴之间的纵向距离为420 mm。重复试验表明：该机明薯率＞96%,伤薯率＜5%。     

基于悬垂平板偏转角的明渠流量估算模型及验证

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残膜回收机起膜器的设计与试验研究

该文在分析残膜回收机具性能的基础上,提出对起膜机构的设计。起膜器是地膜回收机的主要工作部件之一,起膜器主要完成起膜作业,起膜是决定回收地膜效果好坏的一个重要工作环节,它需要完成松土起膜、翻起根茬、膜土分离等几项作业。在收膜工作过程中,让起膜器从膜侧边开始切入,一方面将地膜两边的压膜土耕松,并尽可能地分离地膜与土壤;同时,将根茬切断以方便收膜装置回收地膜,提高地膜回收率。该文对起膜器的结构进行了设计,并考虑了起膜器的正确安装位置,以适应不同作物根茬的地膜幅宽。通过试验,研究起膜器几何参数(刃角δ、切土角α、翼张角β和刃长L)和工作性能参数(工作速度v和耕深h)在不同组合时的性能,并通过MATLAB最优化方法确定出最佳参数。通过田间试验,对起膜器几何参数作适当调整,调整后进一步试验。性能试验结果表明,该起膜器具有较好的膜土分离、切除根茬和耐磨性能,工作性能良好。其结构简单,加工制造方便