关于混凝土泵车的主动控制研究:数值模型和实验分析 毕业论文外文翻译.doc
《关于混凝土泵车的主动控制研究:数值模型和实验分析 毕业论文外文翻译.doc》由会员分享,可在线阅读,更多相关《关于混凝土泵车的主动控制研究:数值模型和实验分析 毕业论文外文翻译.doc(24页珍藏版)》请在三一文库上搜索。
1、外文翻译ON THE ACTIVE CONTROL OF A TRUCK MOUNTED CONCRETE PUMP: NUMERICAL MODEL AND EXPERIMENTAL ANALYSISC.Ghielmetti, H.Giberti, F.RestaPolytechnic of Milan, Mechanical Department, Via La Masa, 34 - 20156 Milan, ItalyABSTRACTIn this paper the study on the behaviour of a pumping group used in industry t
2、o pump a big amount of concrete will be presented. The characteristics of the pumping group, its working and its mathematical model will be explained. Moreover numerical model results will be compare with the experimental ones. The purpose of this work is to show, through the mathematical model, the
3、 improvement of the pumping group system after the introduction of control. In detail, the aim its, on one hand, to optimize the mechanical lay out in order to support some requirements about concrete flux and pressure and, at the other hand, to develop and complete the control system application of
4、 a bigger work in which the pumping group is a part.1. INTRODUCTIONThe study of this pumping group is inserted to a bigger research in which, in addition to the pump, are studied the vibration problems of an associated boom. Both pumping group and boom form the complete system called “truck mounted
5、concrete boom pump”.In Fig 1 the 3D image of the system including the concrete vessel and the couple of cylinders and the real (test rig) pumping group are shown. In Fig 2 theres an image of a truck on which the pumping group is linked and theres an example of mechanical boom movements. About the bo
6、oms can be said that their main feature is the extent and this distance can be changed, assuming various positions, in function of the situation. There are different kinds of booms and their length is variable from a minimum of 28m to a maximum of 58m.Actually, the study of boom behaviour and booms
7、vibration problems are doing by others bevies and some results about this problems are related in others works (A.N.Arbel, 1981; H.B.Kuntze, U.Hirsch, A.Jacubasch, F.Eberle, B.Goller, 1995).At the other hand the study about concrete and pumping group system for concrete will be described. Retracing
8、the story of the pumped concrete can be said that this is a technique for the transport of freshly mixed concrete, allowing the supply of fresh material in the formwork without the use of any bucket nor conveying belt. It has been known in the world for almost 70 years. Concrete pumps in witch the c
9、oncrete circulates in metal pipes were used in the U.S. as early as 1933. The technique of pumping is widely spread, and has profited from many improvements, particularly on the pumps (for example, high span pumps and pumps with high pressure). Its very widely used in the field of industrial constru
10、ction. There are several advantages compared with the other techniques. The importance of rheological properties of concrete can be attested to by the large body of literature (C.F.Ferraris, F.de Larrard, 1998; H.Mori, Y.Tanigawa, 1992; P.Bartos, 1992; P.F.G. Banfill, 2003) while few are the study a
11、bout the way to pump the concrete (ACI Committee 304, 1995; Kaplan,Francois de Larrard, Thierry Sedran, 2005).In this sense this paper presents the compare between the numerical model and theexperimental tests of a pumping group system for concrete, underlining the good results obtained and with the
12、 aim to integrate the control system of the pumping group in order to improve the complete control system.The pumping group is a system installed on a truck and its aim is to pump a big amount of concrete to a large distance from the cockpit. This is possible because the concrete moves along a pipel
13、ine rigidly connected with a mechanical long boom. The pump develops a variable flow and pressure in function of a type of work requirement.Usually the pumping group is used in dirty field and its in contact with extremely aggressive materials so that, the selected design solution, has to be strong
14、and easily to clean and repair. Fig 1. pumping group system, CAD 3D and real test rig.The pumping group is an alternative volumetric pump with two pistons. One of those sucks up the concrete from the concrete vessel and, at the same time, the other pushes the inert along the pipeline. This motion of
15、 the concrete is discontinuous and, because of this, induces many forces on pipeline due to the friction between concrete and metal pipe and depending upon to the position of the boom. These forces induce dangerous mechanical oscillations on the boom so that its work is compromised. Moreover, the si
16、mple layout and the easy employment of the pumping system makes difficult to adjust the provided flow. Fig 2. K41L truck - mounted concrete boom pump.Its clear that the adjustment of the flow in terms of continuity and regularity of the concrete flux inside the metal pipe is fundamental to decrease
17、the oscillations on the entire system and especially of the boom. There isnt in literature a complete study of the pumping group in terms of mechanical and hydraulic models so, for this reasons, it was necessary to develop a mathematical model and an experimental test rig. The mathematical model is
18、helpful in order to adjust the pump flow, reduce the forces on the mechanical boom and optimize the pumping group design in terms of overpressure problems, noise problems, duration and pumping capacity.Moreover, in the paper, will be well describe the physical system, the experimental tests doing on
19、 the real model, the mathematical model and control system associated to the pump.2. DESCRIPTION OF THE ENTIRE SYSTEMIn Fig 3 the pumping group test rig and the block diagram are shown; the position of the group, its constrains with the ground, its lean and all the circuits simulate perfectly the re
20、al group on the truck.The pump was positioned on steel ground constrained structure which has the same connections of the truck - mounted concrete boom pump so that the simulation is the most possible near to reality. The test rig is composed by the pumping group (the physical model in which we are
21、interested) and by a pair of auxiliary circuits; the hydraulic one and the similar concrete one (called CLS circuit). Both the hydraulic circuit, connected to a diesel engines, and the CLS one are similar to the real system.The work fluid (see CLS in Fig 3), flows in a dedicate circuit that is conne
22、ct with a steel tank of almost three meters high. Moreover it goes out alternatively from the concrete side pipes and, through the CLS circuit, puts itself into the steel tank from which, at the same time, come back to the pumping group concrete vessel. On board of CLS circuit a series of valves are
23、 mounted in order to pilot and to adjust the pressure of fluid or, to put it better, the load to which the pistons are subjected from outside.Fig 3. real test rig and test rig block diagram.The Fig 4 shows a scheme of the pumps block connected with the pumping group and with its auxiliary parts. Its
24、 to say that with this complete test rig is possible to make many type of experimental tests and in particular, the variation of the pump rpm and the variation of the dimension of reducing valve, permit us to check, compare and control some important state variables like the flux of oil and concrete
- 配套讲稿:
如PPT文件的首页显示word图标,表示该PPT已包含配套word讲稿。双击word图标可打开word文档。
- 特殊限制:
部分文档作品中含有的国旗、国徽等图片,仅作为作品整体效果示例展示,禁止商用。设计者仅对作品中独创性部分享有著作权。
- 关 键 词:
- 关于混凝土泵车的主动控制研究:数值模型和实验分析 毕业论文外文翻译 关于 混凝土泵 主动 控制 研究 数值 模型 实验 分析 毕业论文 外文 翻译
链接地址:https://www.31doc.com/p-2177411.html