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柠条收获机圆盘锯式切割系统动力学仿真与参数优化 总被引:3,自引:0,他引:3
根据圆盘锯式切割系统的各部件的尺寸参数、柠条参数,在三维实体建模软件UG中建立单组切割部件和切割对象柠条的简化模型,导入动力学分析软件ADAMS中,对对象进行柔性体替换,进行刚柔耦合动力学特性分析。以切割锯盘的直径、厚度和切割部件的转速为影响因素,选取切割系统与柠条的作用力在各向的分力为评价指标表征柠条平茬效率,对影响平茬效率和功率的参数进行了三因素三水平的虚拟正交试验,得到各指标的响应面回归方程,并通过田间试验进行验证及对比分析。结果表明,当切割锯盘直径为400 mm,切割锯盘厚度为5 mm,切割部件转速为1500 r/min时,单组切割部件的切割功率为12.32 kW,柠条收获机的平茬效果最好。 相似文献
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为分析圆盘锯式切割系统的切割机理,在Solidworks中建立单组圆盘锯及灌木枝条的简化模型,并在动力学分析软件ABAQUS中进行仿真分析,研究灌木切割过程中工作参数与圆锯片参数的关系。同时,以锯片转速、行进速度、枝径为影响因素,以锯切力为评价指标,对其影响的因素进行虚拟正交试验,并用Design Expert动态响应软件进行分析,得到响应面回归方程,得知当圆锯转速为2500r/min、前进速度为0.9m/s时平茬效果较好。用小型灌木平茬机上进行实地试验,结果表明破茬率和留茬高度均能满足农艺要求。 相似文献
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针对果树苗木的平茬处理,采用机械圆盘锯切可以提高锯切效率,但平茬要保证切割质量,平茬质量与切割器具有重大关系,切割过程中切割器的振动会造成苗木的损坏。通过分析模态的基本理论达朗贝尔原理及贝塞尔函数,推导切割器的固有频率70.002 Hz,通过简化切割器的运动函数公式得出锯齿与锯盘固有频率的关系,并采用计算机有限元分析圆盘锯的模态参数,得出圆盘锯的一阶极限转速4 539.6 r/min和固有频率75.66 Hz,并将得出的结果为切割器的设计优化提供理论依据和参考依据。通过田间试验测量出发生振动时最大损伤位移值为31 mm,机具在平稳运行时可以有效降低茬口损伤。 相似文献
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《Journal of Agricultural Engineering Research》1998,69(3):249-254
A model to represent the discolouration of dried powder of carrots as a function of temperature was developed. Two types of carrots, Asian and European, containing large amount of lycopene and β-carotene, respectively, were tested. The dried powder was stored under an atmosphere with O2and at three different temperatures, 5,20 and 35°C. The surface colour of the powder was monitored during storage by a Hunter colour ratioa/b. In the proposed model, the rate of oxidation was assumed to be represented by the product of the fraction of concentration of oxidized pigment at arbitrary time and a specific rate of oxidation of pigment. The rate parameters in the proposed model were calculated by fitting the experimental data with smooth curves by trial and error at the end of the induction period but before discolouration took place. The frequency constant and activation energy, expressing the temperature dependence of the rate parameters, were expressed by the Arrhenius relation. The simulation results of a Hunter colour ratioa/bof dried powder at 25°C showed good agreement with the experimental data, suggesting that the proposed model was effective for the prediction of discolouration of dried powder of both types of carrot. The use of the induction period in the manner described may enable the shelf life of dried powder to be predicted. 相似文献
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感官检验棉花的品级,这是农村常见的一种检测手段.它的一个主要特点就是存在不确定性.这是由于检验员的品级检验水平存在一定的差异,其中有很多因素制约着检验的结果.文章对影响感官检验结果的因素进行了系统的分析. 相似文献
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The fractional outflow rate of water from the rumen, measured as the rate of disappearance of the chromium complex of ethylenediamine tetra-acetic acid, was related to a number of dietary factors. A multiple regression equation was derived which expressed fractional outflow rate as a function of the intakes of dry matter, ash, acid-detergent fibre and crude protein.The data analysed consisted of 243 observations for sheep on 59 diets, including forage, concentrate and mixed diets. The ranges covered by the data were: fractional outflow rate 0.7–3.6 day?1; dry matter intake 560–1400g/day; ash 4–30%, acid-detergent fibre 7–41%, crude protein 5–26 % of dry matter; there were no observations for sheep of less than 34 kg liveweight.The equation accounted for 56·3 % of the total variance. Between-sheep variance could not be calculated for the whole of the data but was undoubtedly substantial since, for a sixth of the data, it was known to account for 38 % of the total variance. 相似文献
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从灾害经济学的角度探讨了城镇供水优化调度的必要性和可能性,认为在缺水不可避免的情况下,对供水进行优化调度可以减小缺水带来的损失,产生较好的减灾效益,特别是可以大大减小严重干旱的灾害效应。并根据水资源的特性,提出了缺水损失的计算模式以及优化调度的原则和方法。 相似文献