紫花苜蓿圆捆机卷压过程的应力松弛特性与模型建立
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摘要
牧草属于粘弹性物料,研究其应力松弛特性对降低圆捆机功耗、提高草捆质量具有重要意义。该文通过搭建圆捆机试验平台,结合各钢辊对草捆径向作用力分析,进行了紫花苜蓿应力松弛试验。采用无线电阻应变仪与ANSYS模拟相结合的方法,获取了卷压过程中捆室上半部分钢辊对草捆的径向作用力。在对应力松弛试验曲线和模型原理分析的基础上,确定了牧草应力松弛行为可采用2个Maxwell元件和1个弹簧元件并联组成的广义麦克斯韦尔模型模拟。利用残数法求得模型中应力松弛时间和平衡应力流变参数,分别为76.92、23.25 s和3.65 k Pa。该研究可为进一步探索喂入量、压缩频率、含水率与物料流变特性等参数间的关系,为节能圆捆机的设计提供理论依据及技术支持。
Grass used as a high-quality animal feed has been grown in large scale in China. It is very important to study its stress relaxation characteristics to reduce the power consumption of round bales and improve the quality of bales. In order to understand the stress relaxation characteristics of alfalfa in course of rotary compression, a rotary compression test platform was designed using a steel-roll round baler. The radial forces of steel rolls to the bale during rotary compression were analyzed. Because of the different location of the steel roller of the baling chamber, the radial force of the steel roller to the bale is also different. The radial stress of the steel roll of the upper part of the baling chamber to the bale during rotary compression was obtained through the combination of the wireless resistance strain gauge and the ANSYS simulation. On the basis of the analysis of the stress relaxation test curve and the model principle, it is determined that the stress relaxation behavior of herbage can be simulated by a generalized Maxwell model composed of 2 Maxwell elements and 1 spring element in parallel. Residual stress method is used to get stress relaxation time and equilibrium stress rheological parameters in the model, which were 76.92 s, 23.25 s and 3.65 kP a respectively. The coefficient of determination(R2) was used to evaluate the model fit to the experimental data. The parameters of stress relaxation were analyzed. The moduli of the 2 Maxwell elements were E1 = 1.88/ε1 and E2 = 6.1/ε2. The modulus of the material was not changed during the relaxation process. The stress relaxation times were T1 = η1/E1= 76.92 s and T2= η2/E2 = 23.25 s. It reflected the relaxation speed of the material and the stress relaxation time of each Maxwell element is independent of each other. The initial stress for stress relaxation was 11.63 k Pa(σ = σ1 + σ2 + 3.65), and the equilibrium stress was 3.65 k Pa. This study provides a theoretical basis and technical support for the further exploration of the relationship between feed volume, compression frequency, water content and rheological properties of materials and for the design of energy saving baler.
Grass used as a high-quality animal feed has been grown in large scale in China. It is very important to study its stress relaxation characteristics to reduce the power consumption of round bales and improve the quality of bales. In order to understand the stress relaxation characteristics of alfalfa in course of rotary compression, a rotary compression test platform was designed using a steel-roll round baler. The radial forces of steel rolls to the bale during rotary compression were analyzed. Because of the different location of the steel roller of the baling chamber, the radial force of the steel roller to the bale is also different. The radial stress of the steel roll of the upper part of the baling chamber to the bale during rotary compression was obtained through the combination of the wireless resistance strain gauge and the ANSYS simulation. On the basis of the analysis of the stress relaxation test curve and the model principle, it is determined that the stress relaxation behavior of herbage can be simulated by a generalized Maxwell model composed of 2 Maxwell elements and 1 spring element in parallel. Residual stress method is used to get stress relaxation time and equilibrium stress rheological parameters in the model, which were 76.92 s, 23.25 s and 3.65 kP a respectively. The coefficient of determination(R2) was used to evaluate the model fit to the experimental data. The parameters of stress relaxation were analyzed. The moduli of the 2 Maxwell elements were E1 = 1.88/ε1 and E2 = 6.1/ε2. The modulus of the material was not changed during the relaxation process. The stress relaxation times were T1 = η1/E1= 76.92 s and T2= η2/E2 = 23.25 s. It reflected the relaxation speed of the material and the stress relaxation time of each Maxwell element is independent of each other. The initial stress for stress relaxation was 11.63 k Pa(σ = σ1 + σ2 + 3.65), and the equilibrium stress was 3.65 k Pa. This study provides a theoretical basis and technical support for the further exploration of the relationship between feed volume, compression frequency, water content and rheological properties of materials and for the design of energy saving baler.
引文
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[19]中华人民共和国机械行业标准.牧草捡拾器:JB/T5160-2010[S].北京:机械电子工业部,1991.
[20]赵何.碎玉米秸秆卷压特性的研究[D].泰安:山东农业大学,2010.Zhao He.Study on Rotary Compression Characteristic of Chopped Corn Stalks[D].Taian:Shandong Agricultural University,2010.(in Chinese with English abstract)
[21]聂毓琴,马洪顺,韩志武.薇菜压缩应力松弛与蠕变力学特性研究[J].农业机械学报,2005(4):89-91.Nie Yuqin,Ma Hongshun,Han Zhiwu.Research on stress relaxation and creep mechanics behaviors of osmunda cinnamomea[J].Transactions of the Chinese Society for Agricultural Machinery,2005(4):89-91.(in Chinese with English abstract)
[22]王菊霞,崔清亮,李红波,等.基于流变特性的不同品种苹果果皮质地评价[J].农业工程学报,2016,32(21):305-314.Wang Junxia,Cui Qingliang,Li Hongbo,et al.Evaluation on peels texture of different apple cultivars based on rheological properties[J].Transactions of the Chinese Society of Agricultural Engineering(Transactions of the CSAE),2016,32(21):305-314.(in Chinese with English abstract)
[23]马彦华,宣传忠,武佩,等.玉米秸秆振动压缩过程的应力松弛试验[J].农业工程学报,2016,32(19):88-94.Ma Yanhua,Xuan Chuanzhong,Wu Pei,et al.Experiment on stress relaxation of corn stover during compression with assisted vibration[J].Transactions of the Chinese Society of Agricultural Engineering(Transactions of the CSAE),2016,32(19):88-94.(in Chinese with English abstract)
[24]杨晓清,王春光.果品静载流变特性的研究进展[J].农业工程学报,2005,21(9):178-182.Yang Xiaoqing,Wang Chunguang.Review of research advances in rheological properties of fruits under static loading[J].Transactions of the Chinese Society of Agricultural Engineering(Transactions of the CSAE),2005,21(9):178-182.(in Chinese with English abstract)
[25]Aline Bauer,Luo Gu,Brian Kwee,et al.Hydrogel substrate stress-relaxation regulates the spreading and proliferation of mouse myoblasts[J].Acta Biomaterialia,2017.
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[2]王德福,张全超,杨星,等.秸秆圆捆机捆绳机构的参数优化与试验[J].农业工程学报,2016,32(14):55-61.Wang Defu,Zhang Quanchao,Yang Xing,et al.Parameter optimization and experiment of rope-winding mechanism of straw round balers[J].Transactions of the Chinese Society of Agricultural Engineering(Transactions of the CSAE),2016,32(14):43-45.(in Chinese with English abstract)
[3]李叶龙,王德福,王沫,等.稻秆圆捆机辊盘式卷捆机构的设计及参数优化[J].农业工程学报,2017,33(6):27-34.Li Yelong,Wang Defu,Wang Mo,et al.Design and parameters optimization of roll-disk baling mechanism for rice straw round baler[J].Transactions of the Chinese Society of Agricultural Engineering(Transactions of the CSAE),2017,33(6):43-45.(in Chinese with English abstract)
[4]杨明韶,张永,李旭英.粗纤维物料压缩过程的一般流变规律的探讨[J].农业工程学报,2002,18(1):135-137.Yang Mingshao,Zhang Yong,Li Xuying.Rheological law of the crop stem fibrous material during compression process[J].Transactions of the Chinese Society of Agricultural Engineering(Transactions of the CSAE),2002,18(1):135-137.(in Chinese with English abstract)
[5]马彦华,宣传忠,武佩,等.玉米秸秆振动压缩过程的应力松弛试验[J].农业工程学报,2016,32(19):88-94.Ma Yanhua,Xuan Chuanzhong,Wu Pei,et al.Experiment on stress relaxation of corn stover during compression with assisted vibration[J].Transactions of the Chinese Society of Agricultural Engineering(Transactions of the CSAE),2016,32(19):88-94.(in Chinese with English abstract)
[6]李旭英,杨明韶,鲁国成,等.苜蓿压捆过程中压缩与恢复应力传递规律[J].农业工程学报,2014,30(16):61-67.Li Xunying,Yang Mingshao,Lu Guocheng,et al.Transfer rule of compression and springback stress in compression process of alfalfa[J].Transactions of the Chinese Society of Agricultural Engineering(Transactions of the CSAE),2014,30(16):61-67.(in Chinese with English abstract)
[7]杨明韶,杜建民,李旭英.新鲜草物料压缩过程中应力松弛的试验研究[J].农机化研究,2006,2:100-103.Yang Mingshao,Du Jianmin,Li Xunying.An experimental study of fresh herbage material stress relaxation in the process of compression[J].Journal of Agricultural Mechanization Research,2006,2:100-103.(in Chinese with English abstract)
[8]宫泽奇.青贮玉米秸秆螺旋致密成型工艺及压缩过程流变学试验研究[D].北京:中国农业大学,2017.Gong Zeqi.The Experimental Study on Rheology of Silagecorn Stalk in the Mechanized Spiral Dense Forming Process[D].Beijing:Chian Agricultural University,2017.(in Chinese with English abstract)
[9]朱凯,牛智有.粉体棉花秸秆的应力松弛特性与模型建立[J].华中农业大学学报,2014,33(5):130-134.Zhu Kai,Niu Zhiyou.Compression stress relaxation characteristic of cotton stalk particles and its model building of cot[J].Journal of Huazhong Agricultural University,2014,33(5):130-134.(in Chinese with English abstract)
[10]廖娜,陈龙健,黄光群,等.玉米秸秆木质纤维含量与应力松弛特性关联度研究[J].农业机械学报,2011,42(12):127-132.Liao Na,Chen Longjian,Huang Guangqun,et al.Grey relation analysis of lignocellulose content and compression stress relaxation of corn stalk[J].Transactions of the Chinese Society for Agricultural Machinery,2011,42(12):127-132.(in Chinese with English abstract)
[11]郭文斌,王春光,刘百顺.马铃薯应力松弛特性[J].农业机械学报,2008(2):205-207.Guo Wenbin,Wang Chunguang,Liu Baishun.Stress relaxation characteristics of potato[J].Transactions of the Chinese Society for Agricultural Machinery,2008(02):205-207.(in Chinese with English abstract)
[12]许永亮,熊善柏,赵思明.蒸煮工艺和化学成分对米饭应力松弛特性的影响[J].农业工程学报,2007,23(10):235-240.Xu Yongliang,Xiong Shanbo,Zhao Siming.Effect of cooking technology and chemical components on stressrelaxation property of cooked rice[J].Transactions of the Chinese Society of Agricultural Engineering(Transactions of the CSAE),2007,23(10):235-240.(in Chinese with English abstract)
[13]李汝莘,耿爱军,赵何,等.碎玉米秸秆卷压过程的流变行为试验[J].农业工程学报,2012,28(18):30-35.Li Ruxin,Geng Aijun,Zhao He,et al.Rheologic behavior of chopped corn stalks during rotary compression[J].Transactions of the Chinese Society of Agricultural Engineering(Transactions of the CSAE),2012,28(18):30-35.(in Chinese with English abstract)
[14]雷军乐,王德福,张全超,等.完整稻秆卷压过程应力松弛试验[J].农业工程学报,2015,31(8):76-83.Lei Junle,Wang Defu,Zhan Quanchao,et al.Experiment on stress relaxation characteristics of intact rice straw during rotary compression[J].Transactions of the Chinese Society of Agricultural Engineering(Transactions of the CSAE),2015,31(8):30-35.(in Chinese with English abstract)
[15]李旭英.草物料压缩流变动力学特性研究及压缩过程优化[D].呼和浩特:内蒙古农业大学,2006.Li Xuying.Rheodynamic Characteristics of Herbage Materials in Compression and Optimization of Compression Process[D].Hohhot:Inner Mongolia Agricultural University,2006.(in Chinese with English abstract)
[16]Hu J,Lei T.Stress relaxation in straw molding[J].Bio Resources,2009,4(3):1158-1167.
[17]周庆安,杨培志.我国苜蓿饲草产业的发展现状与思考[J].中国奶牛,2017(5):54-56.Zhou Qingan,Yang Peizhi.Development situation and think of alfalfa forage grass industry in china[J].China Dairy Cattle,2017(5):54-56.(in Chinese with English abstract)
[18]张玲,李菲菲,孙艳梅,等.国内主要品种苜蓿营养价值分析与育种现状及发展历程[J].中国奶牛,2017(11):43-49.Zhang Ling,Sun Feifei,Sun Yanmei,et al.Evaluation on the nutritional value,breeding and development history of main alfalfa(Medicago Sativa)varieties in China[J].China Dairy Cattle,2017(11):43-49.(in Chinese with English abstract)
[19]中华人民共和国机械行业标准.牧草捡拾器:JB/T5160-2010[S].北京:机械电子工业部,1991.
[20]赵何.碎玉米秸秆卷压特性的研究[D].泰安:山东农业大学,2010.Zhao He.Study on Rotary Compression Characteristic of Chopped Corn Stalks[D].Taian:Shandong Agricultural University,2010.(in Chinese with English abstract)
[21]聂毓琴,马洪顺,韩志武.薇菜压缩应力松弛与蠕变力学特性研究[J].农业机械学报,2005(4):89-91.Nie Yuqin,Ma Hongshun,Han Zhiwu.Research on stress relaxation and creep mechanics behaviors of osmunda cinnamomea[J].Transactions of the Chinese Society for Agricultural Machinery,2005(4):89-91.(in Chinese with English abstract)
[22]王菊霞,崔清亮,李红波,等.基于流变特性的不同品种苹果果皮质地评价[J].农业工程学报,2016,32(21):305-314.Wang Junxia,Cui Qingliang,Li Hongbo,et al.Evaluation on peels texture of different apple cultivars based on rheological properties[J].Transactions of the Chinese Society of Agricultural Engineering(Transactions of the CSAE),2016,32(21):305-314.(in Chinese with English abstract)
[23]马彦华,宣传忠,武佩,等.玉米秸秆振动压缩过程的应力松弛试验[J].农业工程学报,2016,32(19):88-94.Ma Yanhua,Xuan Chuanzhong,Wu Pei,et al.Experiment on stress relaxation of corn stover during compression with assisted vibration[J].Transactions of the Chinese Society of Agricultural Engineering(Transactions of the CSAE),2016,32(19):88-94.(in Chinese with English abstract)
[24]杨晓清,王春光.果品静载流变特性的研究进展[J].农业工程学报,2005,21(9):178-182.Yang Xiaoqing,Wang Chunguang.Review of research advances in rheological properties of fruits under static loading[J].Transactions of the Chinese Society of Agricultural Engineering(Transactions of the CSAE),2005,21(9):178-182.(in Chinese with English abstract)
[25]Aline Bauer,Luo Gu,Brian Kwee,et al.Hydrogel substrate stress-relaxation regulates the spreading and proliferation of mouse myoblasts[J].Acta Biomaterialia,2017.
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