基于ANSYS Workbench双圆盘割草机连接架模态分析

为了研究9YG-130型前置式双圆盘割草机的动态特性,以其连接架为研究对象,通过SolidWorks对前置式双圆盘割草机的连接架进行三维实体建模,通过接口导入ANSYS Workbench中,利用ANSYS Workbench对连接架进行了模态分析,确定了连接架的固有频率和振型特征,得到了其前6阶模态振型从317.85~935.55Hz之间的变化规律。当阻止外加激励频率与固有频率接近时,可避免因共振引起割草机作业质量下降,研究结果为后续有限元分析和产品优化提供了依据。     

双圆盘割草机切割器虚拟样机设计与试验

应用SolidWorks的参数化设计功能建立9YG-130型双圆盘割草机切割器各零部件三维实体模型,通过约束装配完成虚拟样机设计,将模型导入动力学分析软件ADAMS后进行运动仿真,得到了切割机构在前进速度2.78 m/s、刀盘转速2 000 r/min时刀片顶点的运行轨迹,根据运动轨迹可计算其重割面积。对模型进行四因素三水平虚拟正交试验,采用Design-Expect 8.0软件进行方差分析,结果表明,最佳取值为vg=57.01 m/s,vj=2.76 m/s,h=34.06 mm,m=3时割草机的重割率得到有效降低。通过实际样机试验结果验证了该设计满足割草机对草业技术的要求,提高了设计效率和准确性。     

基于ANSYS的柠条圆盘锯式切割部件有限元分析

柠条圆盘锯式切割部件是柠条联合收割机的关键部件。为此,通过分析圆盘锯式切割部件的工作特性,结合柠条收割要求,确定三圆盘锯式切割部件的各部件的尺寸参数,并利用三维实体建模软件UG建立切割部件模型,导入有限元分析软件ANSYS中进行结构静力学分析,对单个锯齿上刃部点在不同切割深度下的应力、应变进行仿真分析,旨在为优化柠条收割机切割部件结构参数设计提供依据。     

9YG-130型双圆盘割草机

9YG-130型双圆盘割草机主要适用于牧草的切割与铺条作业。该机具有结构合理、工作可靠、性能稳定、操作方便等优点．是牧场和牧草专业户使用的理想机型。     

柠条收割机圆盘锯式切割部件运动学仿真

圆盘锯式切割部件是柠条联合收割机的关键部件。分析圆盘锯式切割部件的运动过程,结合柠条收割要求,建立三圆盘锯式切割部件的运动参数表达式,并利用UG NX软件建立切割部件模型,导入机械动力学仿真分析软件ADAMS进行动力学分析,对单个锯齿上刃部点的运动轨迹进行仿真分析研究,为柠条收割机结构参数设计提供依据。      

双圆盘割草机传动系的应力应变及振动特性分析

建立了9YG—130型前置式双圆盘割草机第一级传动系的三维模型并进行装配,利用ANSYS Workbench软件建立了装配体的有限元分析模型,对传动系进行了结构的强度、刚度校核及模态分析。通过对有限元计算结果的分析,得到应力、应变分布情况及固有频率和振型特征。结果表明,采用虚拟设计可以显著加快设计进度,改进产品设计质量,为农业机械的虚拟样机后续拓扑优化提供了参考依据。     

胡萝卜联合收获机拉齐切割装置设计与试验

拉齐切割装置是胡萝卜联合收获机的重要工作部件,其性能好坏直接决定了秧苗切口位置是否统一平整,切割是否干净。针对我国胡萝卜主产区的种植模式和农艺要求,研制了一种应用于双行胡萝卜联合收获机上的双圆盘刀式拉齐切割装置,该装置主要由拉齐部件、切割部件和水平夹持输送部件等组成,一次作业可完成胡萝卜的拉齐、切割、抛秧等功能。该装置采用双圆盘刀作为切割部件,切口平整美观,切割效果好;采用挡板作为拉齐部件,挡板的高度及中间缝隙的大小均可调;采用上下两层夹持带作为水平夹持输送部件,能够有效防止胡萝卜秧叶倒伏,有利于后续的切割及抛秧作业。该装置的成功研发解决了机械收获时胡萝卜切口不美观、拉齐效果差以及堵秧的问题,有效提高了胡萝卜联合收获机的收获效果。      

锯齿形双圆盘切割器切割原理分析与仿真

以锯齿形双圆盘切割器作为研究对象,分析研究了圆盘刀滑动切割的工作原理,建立了影响切割效率的参数模型,从切割稳定性和效率角度,确定了合理的线性切割角度范围;仿真分析了圆盘刀切割运动轨迹变化规律,给出圆盘式切割器的合理转动速度;同时,对圆盘刀进行了模态分析,明确了圆盘刀的固有频率和各阶模态,为实际工作避开扭转振动状态提供设计依据。研究结果表明,保证了锯齿形双圆盘切割器设计的合理性和可靠性,解决了甜高粱果穗和茎秆的高效切割技术问题,为高秆植株作物茎穗联合收获技术研究提供参考依据。     

基于Solidworks可折叠货物机械装置建模与装配

应用Solidworks软件对可携式货物上下车助力机械装置各部分零件进行建模,分模块进行装配。本次建模,实现了对可携式货物上下车助力机械装置的虚拟设计,为实际生产制造提供设计装配模型,缩短了产品的研发周期,节约了开发成本,提高实际生产的效率与产品的可靠性。     

9YG—130型双圆盘割草机齿轮传动系统动力学仿真

9YG—130型双圆盘割草机齿轮传动系统运行的平稳性在机组工作过程中具有很大的影响。为此,运用Solidworks三维建模软件,基于圆锥齿轮齿廓表面形成原理和圆锥齿轮球面渐开线方程绘制直齿锥齿轮,并进行装配。同时,应用虚拟样机仿真分析软件ADAMS,基于冲击函数法对样机进行运动仿真,得到角速度、角加速度以及轮齿啮合力等参数特性曲线,并对特性曲线进行分析。分析结果表明:在主动轮转速达到2 000r/min时,从动锥齿轮的速度呈现出在12 000d/s(即2 000r/min)附近上下波动的情况,轮齿啮合力也呈现出在某一值附近上下波动的情况,符合锥齿轮传动系统实际工作中的运行规律,并且也体现出传动系统运行的平稳性,可为动态特性优化提供理论参数。     

Overland water and salt flows in a set of rice paddies

Cultivation of paddy rice in semiarid areas of the world faces problems related to water scarcity. This paper aims at characterizing water use in a set of paddies located in the central Ebro basin of Spain using experimentation and computer simulation. A commercial field with six interconnected paddies, with a total area of 5.31 ha, was instrumented to measure discharge and water quality at the inflow and at the runoff outlet. The soil was classified as a Typic Calcixerept, and was characterized by a mild salinity (2.5 dS m⁻¹) and an infiltration rate of 5.8 mm day⁻¹. The evolution of flow depth at all paddies was recorded. Data from the 2002 rice-growing season was elaborated using a mass balance approach to estimate the infiltration rate and the evolution of discharge between paddies. Seasonal crop evapotranspiration, estimated with the surface renewal method, was 731 mm (5.1 mm day⁻¹), very similar to that of other summer cereals grown in the area, like corn. The irrigation input was 1874 mm, deep percolation was 830 mm and surface runoff was 372 mm. Irrigation efficiency was estimated as 41%. The quality of surface runoff water was slightly degraded due to evapoconcentration and to the contact with the soil. During the period 2001–2003, the electrical conductivity of surface runoff water was 54% higher than that of irrigation water. However, the runoff water was suitable for irrigation. A mechanistic mass balance model of inter-paddy water flow permitted to conclude that improvements in irrigation efficiency cannot be easily obtained in the experimental conditions. Since deep percolation losses more than double surface runoff losses, a reduction in irrigation discharge would not have much room for efficiency improvement. Simulations also showed that rice irrigation performance was not negatively affected by the fluctuating inflow hydrograph. These hydrographs are typical of turnouts located at the tail end of tertiary irrigation ditches. In fact, these are the sites where rice has been historically cultivated in the study area, since local soils are often saline-sodic and can only grow paddy rice taking advantage of the low salinity of the irrigation water. The low infiltration rate characteristic of these saline-sodic soils (an experimental value of 3.2 mm day⁻¹ was obtained) combined with a reduced irrigation discharge resulted in a simulated irrigation efficiency of 60%. Paddy rice irrigation efficiency can attain reasonable values in the local saline-sodic soils, where the infiltration rate is clearly smaller than the average daily rice evapotranspiration.     

瓦房店市水果生产标准化发展研究

瓦房店市是我国重要的水果生产基地,在国内水果生产领域占有重要地位。随着水果市场化的不断深入,如何满足和适应国内外市场需求成为瓦房店市水果生产的关键问题。从瓦房店市水果生产实际出发,阐述了实施水果生产标准化的必要性,提出了发展水果生产标准化的具体措施。     

金谷子耐旱TG118引种试种及推广应用

对引进的谷子新品种金谷子耐旱TG118进行品种比较试验和多点试种。结果表明：该品种抗旱、耐瘠、适应性强,稳产、高产、抗病抗风抗倒伏强,品质优良,粮草兼用,种植简单,省工易管;一般产量在6000kg/hm2以上,比当地主栽品种增产20%以上。最高产量达9450kg/hm2,适于在辽西北地区推广应用。     

对《种子法》存在问题的探讨

《种子法》是我国种植业第一部法律。自实施以来,为依法加强种子管理提供了有力的法律支撑,促进我国种子产业发生翻天覆地的变化。但随着依法管理工作的深入和种子产业的快速发展,《种子法》及配套规章的一些问题逐步显现出来。对《种子法》及配套规章存在的问题进行深入分析,对需要进一步补充的章节以及需要调整的内容进行深入探讨,以求更加完善和明确。     

Review of the Egyptian experience in implementing land drainage projects

About 30 years have passed since the Government of Egypt embarked on implementing a series of large scale drainage projects. At present, about 3.8 million acres have been provided with drainage systems on the basis of systematic pre-drainage investigations and designs. The target is to provide drains in approximately 6.4 million acres in the Nile Valley and Delta.The implementation of the subsurface drainage system is carried out by the public sector and private contractors under direct supervision of governmental regional departments. The implementation process depends on many factors related to the drainage material, machinery, manpower, site requirements, farmers and organizations involved. Problems and constraints are sometimes challenging, however, the annual rate of implementation has gradually increased to 170,000 acre/year.This paper discusses the different aspects involved in the implementation process of drainage systems. The development in materials, machinery and construction technologies will be reviewed. Institutional and management factors are going to be also considered.     

和谐社会理论建设的几点哲学思考

在新世纪,面对机遇和挑战,党的十六大把“社会更加和谐”作为全面建设更高水平的小康社会的一个重要目标。中国人素有社会和谐的理想;西方人自古也向往社会和谐;借鉴东西方两种和谐社会思想的经验、教训,构建社会主义和谐社会理论。     

A European irrigation map for spatially distributed agricultural modelling

We present a pan-European irrigation map based on regional European statistics, a European land use map and a global irrigation map. The map provides spatial information on the distribution of irrigated areas per crop type which allows determining irrigated areas at the level of spatial modelling units. The map is a requirement for a European scale assessment of the impacts of irrigated agriculture on water resources based on spatially distributed modelling of crop growth and water balance. The irrigation map was compiled in a two step procedure. First, irrigated areas were distributed to potentially irrigated crops at a regional level (European statistical regions NUTS3), combining Farm Structure Survey (FSS) data on irrigated area, crop-specific irrigated area for crops whenever available, and total crop area. Second, crop-specific irrigated area was distributed within each statistical region based on the crop distribution given in our land use map. A global map of irrigated areas with a 5′ resolution was used to further constrain the distribution within each NUTS3 based on the density of irrigated areas. The constrained distribution of irrigated areas as taken from statistics to a high resolution dataset enables us to estimate irrigated areas for various spatial entities, including administrative, natural and artificial units, providing a reasonable input scenario for large-scale distributed modelling applications. The dataset bridges a gap between global datasets and detailed regional data on the distribution of irrigated areas and provides information for various assessments and modelling applications.     

粉质仪和拉伸仪在面粉生产中的应用

在介绍粉质仪和拉伸仪结构和原理的基础上,探讨了粉质曲线中吸水率、形成时间、稳定时间、弱化度和评价值等指标与面粉品质的关系,以及如何根据拉伸曲线中面团最大拉伸阻力、延伸度和拉伸曲线面积等指标来评价面团品质,并结合生产实际,概述了粉质仪和拉伸仪在面粉生产中的作用。     

农村信息化服务的现状及建设措施

分析当前我国农村信息化服务的现状,提出加强农村信息化服务的新举措。     

车辆ABS控制算法的研究及探讨

对现代汽车的ABS控制算法作了一些简单的介绍,同时指出了它们的一些缺陷,相应地提出了几种对ABS的其它控制方法并加以探讨,其中着重论述了ABS门限值控制算法中参考车速的确定方法和基于附着系数的控制算法。