本文選題：割草壓扁機(jī) + 仿形系統(tǒng)�。� 參考：《中國農(nóng)業(yè)大學(xué)》2017年博士論文

【摘要】：為了實(shí)現(xiàn)苜蓿高效、低損和優(yōu)質(zhì)收獲,論文從苜蓿刈割壓扁收獲機(jī)械工作過程出發(fā),在研究苜蓿莖葉連接力學(xué)特性的基礎(chǔ)上,通過虛擬樣機(jī)技術(shù)與田間試驗(yàn)相結(jié)合,對苜蓿刈割壓扁機(jī)的仿形系統(tǒng)和切割壓扁系統(tǒng)的設(shè)計(jì)參數(shù)進(jìn)行了優(yōu)化,對機(jī)械系統(tǒng)在喂入?yún)^(qū)產(chǎn)生的氣流場進(jìn)行了模擬和實(shí)測研究。論文進(jìn)行了苜蓿莖葉連接力學(xué)特性研究,為機(jī)械系統(tǒng)與苜蓿植株作用過程的研究提供理論參考。對于新鮮苜蓿植株,進(jìn)行拉伸破壞時(shí)的最大載荷值根據(jù)破壞方式不同由大到小的排列順序?yàn)?順茬拉伸、垂直拉伸和逆茬拉伸;順茬拉伸時(shí)莖葉連接點(diǎn)被拉扯破壞,逆茬拉伸時(shí)莖葉連接點(diǎn)被撕裂破壞,而垂直拉伸時(shí)則處于兩者之間,從力學(xué)特性角度分析,收獲時(shí)順茬喂入為理想喂入方式。仿形系統(tǒng)是刈割壓扁機(jī)實(shí)現(xiàn)高效收獲的關(guān)鍵,論文建立了仿形系統(tǒng)的虛擬樣機(jī)模型,并進(jìn)行了四因素三水平虛擬正交實(shí)驗(yàn),以平均割茬高度、割茬穩(wěn)定性系數(shù)和割刀觸土深度為優(yōu)化指標(biāo),得出仿形系統(tǒng)最佳設(shè)計(jì)和工作參數(shù)為滑掌長度188 mm,割臺(tái)傾角4.06°,拉力重力比0.85,前進(jìn)速度2 m/s。在此條件下,利用仿形系統(tǒng)虛擬樣機(jī)仿真的結(jié)果為平均割茬高度為69.77 mm,割茬穩(wěn)定性系數(shù)為46.96%,割刀無觸土現(xiàn)象。切割壓扁系統(tǒng)是刈割壓扁機(jī)實(shí)現(xiàn)低損收獲的關(guān)鍵,論文通過建立切割壓扁系統(tǒng)的虛擬樣機(jī)模型,在不同切割壓扁運(yùn)行參數(shù)下進(jìn)行了仿真試驗(yàn),假設(shè)并定義了評判切割壓扁系統(tǒng)對苜蓿植株的破碎作用程度的碎草系數(shù)ε的模型,得到切割壓扁系統(tǒng)最佳運(yùn)行參數(shù)為割刀轉(zhuǎn)速ng=1875 r/min,壓扁輥轉(zhuǎn)速ny=749 r/min,此時(shí)切割壓扁系統(tǒng)對苜蓿植株的破碎作用最小。樣機(jī)田間試驗(yàn)表明:實(shí)測碎草率與碎草系數(shù)ε呈線性正相關(guān),相關(guān)系數(shù)平方R2=0.9588,驗(yàn)證了碎草系數(shù)模型的正確性。刈割壓扁機(jī)械系統(tǒng)形成的氣流場能輔助完成苜蓿收獲過程,論文利用CFX對喂入?yún)^(qū)氣流場進(jìn)行了模擬計(jì)算,發(fā)現(xiàn)了機(jī)器前方存在"氣流交匯點(diǎn)",通過對氣流速度分析得出,該交匯點(diǎn)上方、后方和前方的氣流分別能起到避免重割、輔助喂入和利于切割的作用。利用響應(yīng)面分析得到了關(guān)鍵氣流場參數(shù)隨切割壓扁運(yùn)行參數(shù)變化的關(guān)系模型。對機(jī)械系統(tǒng)進(jìn)行優(yōu)化后的9GYZ-1.2型自走式苜蓿刈割壓扁機(jī),田間作業(yè)的割茬高度為55.5 mm,超茬損失率為0.31%,碎草率為2.32%,壓扁率為98.36%,均達(dá)到國家標(biāo)準(zhǔn)對刈割壓扁機(jī)作業(yè)質(zhì)量的要求。與人工收獲的未壓扁的苜蓿相比,利用樣機(jī)進(jìn)行壓扁調(diào)制收獲的苜蓿,田間晾曬時(shí)的干燥速率明顯加快,樣機(jī)壓扁調(diào)制取得了理想的效果。
[Abstract]:In order to achieve high efficiency, low loss and high quality harvest of alfalfa, the paper studied the mechanical properties of alfalfa stem and leaf connection, and combined it with field experiment through virtual prototyping technology, based on the working process of cutting and flattening harvesting machine. The design parameters of the copying system and cutting flattening system of alfalfa cutting flattening machine were optimized. The airflow field produced by the mechanical system in the feeding area was simulated and measured. In this paper, the mechanical properties of alfalfa stem and leaf connection are studied, which provides a theoretical reference for the study of the interaction between the mechanical system and alfalfa plants. For fresh alfalfa plants, the order of maximum load during tensile damage was as follows: following stubble stretching, vertical stretching and reverse stubble stretching; The joint point of stem and leaf was torn and destroyed during the extension of the reverse stubble, but it was in the middle of the two in the vertical stretching. From the angle of mechanical properties, the ideal feeding mode was to feed along the stubble at harvest. The copying system is the key to the high efficiency harvest of the cutting and flattening machine. The virtual prototype model of the copying system is established, and the virtual orthogonal experiment of four factors and three levels is carried out to average the stubble height. The optimum design and working parameters of the copying system are as follows: the length of the slide palm is 188 mm, the slope angle of the cutting table is 4.06 擄, the pull gravity ratio is 0.85, and the forward speed is 2 m / s. Under this condition, the simulation results show that the average stubble height is 69.77 mm, the stubble stability coefficient is 46.96, and the cutting knife has no contact with soil. Cutting and flattening system is the key to realize low loss harvest of cutting flattening machine. This paper establishes a virtual prototype model of cutting flattening system and carries out simulation experiments under different cutting flattening operation parameters. Suppose and define the model of breaking coefficient 蔚 of cutting and flattening system to evaluate the degree of fragmentation of alfalfa plants. The optimum operating parameters of the cutting and flattening system were obtained as follows: cutting speed ng=1875 rmin and flattening roll speed ny=749 r / min. At this time, the cutting and flattening system had the least effect on the breaking of alfalfa plants. The field test of the prototype showed that there was a linear positive correlation between the measured sloppiness and the breaking coefficient 蔚, and the correlation coefficient square R _ (2) was 0.958 8, which verified the correctness of the model. The airflow field formed by the cutting and flattening mechanical system can assist in the alfalfa harvest process. In this paper, the air flow field in the feeding area is simulated by CFX, and the "air flow intersection point" in front of the machine is found, which is obtained by the analysis of the airflow velocity. The air flow above, behind and ahead of the intersection can avoid recutting, assist feeding and facilitate cutting. Based on the response surface analysis, the relation model of the key airflow field parameters with the cutting flattening operation parameters is obtained. After optimizing the mechanical system, the 9GYZ-1.2 self-walking cutting and flattening machine of alfalfa, the stubble height of field operation is 55.5mm, the loss rate of excess stubble is 0.31mm, the rate of sloppy crushing is 2.32cm, and the flattening rate is 98.36. All of them meet the requirements of the national standard for the operation quality of cutting flattening machine. Compared with the unflattened alfalfa harvested by artificial harvesting, the drying rate of the alfalfa, which was compressed and modulated by the prototype, was obviously accelerated when it was dried in the field, and the ideal effect was obtained by the flattening modulation of the prototype.
【學(xué)位授予單位】：中國農(nóng)業(yè)大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2017
【分類號】：S817.11

【參考文獻(xiàn)】

相關(guān)期刊論文 前10條

1 趙建柱;孫鳳濤;陳宏偉;孫佳;王德成;;全液壓山地手扶式苜蓿刈割壓扁機(jī)設(shè)計(jì)與試驗(yàn)[J];農(nóng)機(jī)化研究;2017年03期

2 汪武靜;王明利;呂官旺;劉玉鳳;石自忠;;美國苜蓿貿(mào)易——趨勢、經(jīng)驗(yàn)與啟示[J];草業(yè)科學(xué);2016年03期

3 劉輝;卜登攀;呂中旺;李發(fā)弟;劉士杰;張開展;王加啟;;凋萎和不同添加劑對紫花苜蓿青貯品質(zhì)的影響[J];草業(yè)學(xué)報(bào);2015年05期

4 孫雨坤;王林;孫啟忠;徐博;;添加蘋果渣對苜蓿青貯品質(zhì)的影響[J];中國草地學(xué)報(bào);2015年01期

5 趙建柱;郭海林;王楓辰;張?bào)闱?王一如;黃韶炯;;苜蓿草壓扁試驗(yàn)臺(tái)設(shè)計(jì)與試驗(yàn)[J];農(nóng)業(yè)機(jī)械學(xué)報(bào);2014年S1期

6 王坤龍;李兆林;尹強(qiáng);姚家富;王石瑩;陳利娜;;不同青貯方式對紫花苜蓿青貯飼料飼用品質(zhì)的影響[J];飼料博覽;2014年11期

7 卞魯平;趙春花;馬世倫;;割草壓扁機(jī)人字齒橡膠壓扁輥的加工方法[J];甘肅農(nóng)業(yè)大學(xué)學(xué)報(bào);2014年05期

8 劉玉鳳;王明利;胡向東;石自忠;;美國苜蓿產(chǎn)業(yè)發(fā)展及其對中國的啟示[J];農(nóng)業(yè)展望;2014年08期

9 劉顯耀;李慶達(dá);;旋轉(zhuǎn)式割草機(jī)新型割刀工藝探討[J];農(nóng)機(jī)化研究;2014年02期

10 蒙建國;趙滿全;黃炎;張寧;黃鵬飛;;9YG-130型雙圓盤割草機(jī)刀片的運(yùn)動(dòng)仿真研究[J];農(nóng)機(jī)化研究;2013年10期

相關(guān)會(huì)議論文 前1條

1 盧欣石;;中國苜蓿產(chǎn)業(yè)化發(fā)展前景分析[A];草業(yè)與西部大開發(fā)——草業(yè)與西部大開發(fā)學(xué)術(shù)研討會(huì)暨中國草原學(xué)會(huì)2000年學(xué)術(shù)年會(huì)論文集[C];2000年

相關(guān)博士學(xué)位論文 前3條

1 張涵;苜蓿莖稈剪切特性及切割參數(shù)的試驗(yàn)研究[D];中國農(nóng)業(yè)大學(xué);2015年

2 付作立;雙圓盤式刈割壓扁機(jī)切割系統(tǒng)研究[D];中國農(nóng)業(yè)大學(xué);2014年

3 許慶方;影響苜蓿青貯品質(zhì)的主要因素及苜蓿青貯在奶牛日糧中應(yīng)用效果的研究[D];中國農(nóng)業(yè)大學(xué);2005年

相關(guān)碩士學(xué)位論文 前4條

1 陳凱;小型割草壓扁機(jī)壓扁裝置關(guān)鍵部件設(shè)計(jì)與試驗(yàn)研究[D];甘肅農(nóng)業(yè)大學(xué);2015年

2 劉喜林;9GBQ-3.0切割壓扁機(jī)的設(shè)計(jì)[D];內(nèi)蒙古農(nóng)業(yè)大學(xué);2012年

3 張雷;商用乘騎式草坪割草車刀盤流場及動(dòng)力學(xué)特性的研究[D];南京理工大學(xué);2009年

4 邵霞;割草機(jī)流道內(nèi)流場數(shù)值模擬及實(shí)驗(yàn)研究[D];江蘇大學(xué);2007年

，

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