共查询到20条相似文献，搜索用时 93 毫秒
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单圆盘甘蔗切割器影响破头率的运动学仿真 总被引：1，自引：0，他引：1
利用有限元软件ANSYS对甘蔗切割进行有限元分析,制定了单圆盘甘蔗切割器切割甘蔗的坏切割状态判别标准,通过物理试验制定了刀盘压破蔗头的判别标准.利用动力学仿真分析软件ADAMS进行了切割器连续切割多根甘蔗的运动学仿真,定量研究了影响切割状态和压破蔗头的各因素及交互作用对破头率的影响机理.结果表明.小频率和小速比、小振幅和少刀片的组合有利于降低破头率,当频率、振幅为零,速比为24,倾角为15°,刀片数目为2片时破头率为6.7%. 相似文献
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采用ANSYS/LS-DYNA显式动力学仿真软件,建立甘蔗-切割器系统的动力学仿真模型,且进行了甘蔗切割物理试验验证。利用四因子二次通用旋转组合设计方法和甘蔗-切割器系统仿真模型进行一刀切断甘蔗的仿真试验,建立影响因素与切割力和剪应力的数学模型,研究了切割力和剪应力各影响因素及其交互作用的影响规律,且对影响因素进行优化,获得了一刀切断甘蔗时可靠性为95%的最佳切割力总区间。结果表明,刀片刃角为17.5°,切割角为27.73°,刀盘倾角为28°,切割速度为16 m/s时,可靠性为95%的最佳切割力范围为235.82~297.98 N。 相似文献
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单圆盘甘蔗切割器切割破头率影响机理研究 总被引：1，自引：1，他引：0
为了降低甘蔗切割器切割甘蔗的破头率,提高切割质量,在已建立的不同工况下切割器结构因素及振动因素对切割器切割破头率影响的数学模型基础上,分析了各因素对破头率的影响.利用动力学仿真分析软件ADAMS进行了切割器连续切割甘蔗的运动学仿真,通过观察每一根甘蔗的切割状态,并结合图解法研究了各因素对破头率的影响机理.结果表明:频率与振幅对破头率影响显著,切割器设计时应考虑增加减振措施. 相似文献
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为分析小型前悬挂双圆盘牧草收割机切割器的工作性能,通过SolidWorks软件建立切割器三维模型,利用ADAMS软件对切割器刀片完成运动仿真分析,对切割器的输入轴进行有限元力学分析和模态分析。结果显示,刀片上单点运动是以一定的频率波动和振幅前进,切割器的运动满足牧草收割要求;输入轴的最大应力值为28.4 MPa,应力最大处主要集中在轴承颈及键槽附近,输入轴最大应力小于轴的屈服极限,输入轴的最大位移值为0.013 2 mm,应变从轴承位置向齿轮啮合方向逐渐减少,满足强度和刚度要求;振动方式主要为扭曲振动和弯曲振动,当输入轴的工作转速为2 000 r/min时,对应的频率为33.3 Hz,远小于输入轴第一阶频率1 104.5 Hz,机构不会产生共振现象,输入轴能够保证可靠、安全的正常作业。 相似文献
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Overland water and salt flows in a set of rice paddies 总被引：1，自引：0，他引：1
E. Playn O. Prez-Coveta A. Martínez-Cob J. Herrero P. García-Navarro B. Latorre P. Brufau J. Garcs 《Agricultural Water Management》2008,95(6):645-658
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. 相似文献
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车用发动机润滑油失效规律与更换周期研究 总被引：7，自引：0，他引：7
研究在正常使用条件下１０Ｗ／３０－ＱＣ级润滑油用于某型车用发动机时所表现的失效规律,确认期服从两参数Ｗｅｉｂｕｌｌ分布,并给出分布的尺度参数η和形状参数ｍ之最佳线性无偏估计（ＢＬＵＥ）同时,还为定量分析,计算车用发动机润滑油的使用可靠性和合理确定其更换周期提供了一套可供借鉴的方法,并给出了具体的计算实例。 相似文献
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赵国杰 《农业机械化与电气化》2011,(4):106-107
乡（镇）农技推广体系是农业发展的关键。介绍朝阳市农业技术推广体系的现状,针对目前体制及运行机制、服务手段等方面存在的问题,提出适合朝阳市乡（镇）农技推广体系改革与发展的对策,以期对全省农技推广体系改革和发展起到一些借鉴作用。 相似文献
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苑庆刚 《农业机械化与电气化》2010,(3):52-54
草莓果味酸甜爽口,营养价值高,为人们所喜爱的应市鲜果之一。由于草莓易受损伤和微生物侵染,因此其采收、贮藏过程极为重要。介绍草莓采收过程中的注意事项以及11种贮藏保鲜技术的实施步骤和操作方法,推介9种加工方式,为草莓产业化提供技术支持。 相似文献
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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。 相似文献
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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。 相似文献
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对《种子法》存在问题的探讨 总被引：1，自引：0，他引：1
李鹏 《农业机械化与电气化》2011,(6):129-130
《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。 相似文献
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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。 相似文献
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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. 相似文献