|
|
|
| Cutting mechanism of conical pick based on elastic-plastic-fracture theory and test verification |
| WANG Xin1, XU Lanxin2, CHEN Hongyue3,4, BAI Yangxi3, CHEN Hongyan3 |
1. Research Institute of Technology and Equipment for the Exploitation and Utilization of Mineral Resources, Liaoning Technical University, Fuxin 123000, China;
2. College of Management, Xi’an University of Science and Technology, Xi’an 710054, China;
3. College of Mechanical Engineering, Liaoning Technical University, Fuxin 123000, China;
4. China National Coal Association, Dynamic Research for high-end complete Integrated Coal Mining Equipment and Big Data Analysis Center, Fuxin 123000, China |
|
|
|
|
Abstract To study the cutting mechanism of conical pick in process of cutting coal, a mathematical model of external contour of conical pick was established. Based on theories of elastic mechanics, plastic mechanics and fracture mechanics, the theoretical model for elastic-plastic-fracture instability to happen under action of cutting force of pick cutting coal rock was proposed to describe the mechanism of pick cutting coal rock. According to the model, expressions for pick cutting force and coal rock stress under coal rock’s elastic deformation, plastic deformation and fracture instability were derived. Finally, the self-built test equipment was used to perform pick cutting coal rock tests with different cutting angles. The test results showed that during pick cutting force being exerted on coal rock, the contact area between pick and coal rock gradually increases with increase in pick cutting depth, coal rock has elastic deformation stage, plastic deformation one and fracture instability one, and these facts are consistent with what the theoretical model describes; when cutting angle is 90°, 75°, 60°, RMS errors between the theoretical value and the test one of pick cutting resistance are 0.082 kN, 0.199 kN and 0.204 kN, respectively, the difference between the theoretical value and the test one is small to verify the correctness of the theoretical model.
|
|
Received: 12 August 2019
Published: 15 February 2021
|
|
|
|
[1] 刘春生,任春平.改进分数阶Tikhonov正则化的截割煤岩载荷识别方法[J].煤炭学报,2019,44(01):332-339.
LIU Chunsheng,REN Chunping.Identification method of cutting coal and rock load based on improved fractional Tik-honov regularization[J].Journal of China Coal Society,2019,44(01):332－339．
[2] 王想,王清峰,梁运培.截割参数对镐型截齿截割比能耗的影响[J].煤炭学报,2018,43(02):563-570.
WANG Xiang,WANG Qingfeng,LIANG Yunpei.Effects of cutting parameters affecting on specific cutting energy of conical picks[J].Journal of China Coal Society,2018,43(2):563－570．
[3] Evans I. A theory of the cutting force for point-attack picks[J]. Geotechnical & Geological Engineering, 1984, 2(1): 63-71.
[4] I Evans. Basic Mechanics of the Point-Attack Pick [J].Colliery Guardian,1984(02):189-191.
[5] Gokan R M. A suggested improvement on Evans' cutting theory for conical bits.[C]. Proceedings of the Fourth symposium on Mine Mechanization Automation., 1997: 57-61.
[6] FF Roxborough.Mechanical cutting characteristics of lower chalk[J].Tunnels & Tunnelling International,1973,3(5):261-274.
[7] Roxborough Frank F,Phillips Huw R.Experimental studies on the excavation of rock using picks[J].Advances in rock mechanics,reports of current research,1974:1407-1412.
[8] Roxborough Ff L Z.Throretical considerations on pick shape in rock and coal cutting.[C]. Proceedings of the sixth underground operator's conference, 1995: 189-193.
[9] Nishimatsu Y.The mechanics of rock cutting[J]. International Journal of Rock Mechanics & Mining Science & Geomechanics Abstracts, 1972, 9(2): 261-270.
[10] I Nishizawa,S Okubo,Y Nishimatsu,M Akiyama.Cutting Force of Point Attack Bit[J].Shigen-to-Sozai,1991,107(12):859-864.
[11] 王庆康,门迎春.采煤机截割理论[M].北京:煤炭工业出版社,1992.
WANG Qingkang,MEN Yingchun.Cutting Theory of Shearer[M].Beijing:China Coal Industry Publishing House.
[12] 牛东民.煤炭切削力学模型的研究[J].煤炭学报,1994,18(05):526-530.
NIU Dongmin.Mechanical model of coal cutting[J].Journal of China Coal Society,1994,18(05):526-530.
[13] 牛东民.刀具切削破煤机理研究[J].煤炭学报,1993,17(05):49-54.
NIU Dongmin.Study of coal cutting mechanism of cutting tools[J].Journal of China Coal Society,1993,17(05):49-54.
[14] 李勇.高应力硬岩镐形截齿截割破岩研究[D].中南大学,2012.
LI Yong.The Study of cutting hard rock with high stress by the cutting picks[D].Central South University,2012.
[15] 宋杨. 镐型截齿截割煤岩力学特性的数值模拟[D].黑龙江科技大学,2013.
SONG Yang.Numerical simulation of the mechanicalbehavior on conical pickcutting coal[D].Heilongjiang Institute of Science and Technology,2013.
[16] 刘晓辉. 镐型截齿与煤岩互作用力学与磨损特性研究[D].中国矿业大学,2016.
LIU Xiaohui.Research on Mechanical and Wear Characteristic of Conical Pick Interacted with Coal-Rock[D].China University of Mining and Technology,2016.
[17] 徐芝纶.弹性力学[M].北京:高等教育出版社,2006:220-223.
XU Zhilun.Elastic mechanics[M].Beijing:Higher Education Press,2006:220-223.
[18] IN Sneddon.Boussinesq's problem for a flat-ended cylinder[J].Mathematical Proceedings of the Cambridge Philosophical Society,1946,42(1):29-39.
[19] IN Sneddon.Boussinesq's problem for a rigid cone[J].Mathematical Proceedings of the Cambridge Philosophical Society，1948,44(4):492-507.
[20] 郑颖人,孔亮.岩土塑性力学[M].北京:中国建筑工业出版社,2010:58-102.
ZHENG Yingren,SUN Liang.Geotechnical Plastic Mechanics[M].Beijing: China Architecture& Building Press,2010:58-102.
[21] 范天佑.断裂理论基础[M].北京:科学出版社,2003:20-63.
FAN Tianyou.Theoretical basis of fracture[M].Beijing:Science Press,2003:20-63. |
|
|
|
