MR fluids are widely used in various structures such as controlled dampers, brakes, clutches, etc. Application of these fluids can reduce energy costs and weight as well as increase device operational speed and lifetime. In order to exploit all the qualities of MRS and ERS properties it is necessary to occasionally mix the fluids and monitor them. These systems are still under research and development in laboratories worldwide. This article describes the developed and tested flexible bellow, which can determine whether the MR fluid is under influence of sedimentation and whether it can operate correctly or it is necessary to perform the mixin

Dragašius, E.

Kunevicius, J.

Mažeika, D.

Volkovas, V.

Maintenance, Reliability and Condition Monitoring

 582. RESEARCH OF THE FLEXIBLE BELLOW WITH THE  MAGNETORHEOLOGICAL FLUID. D. MAŽEIKA 1, J. KUNEVIČIUS2, V. VOLKOVAS3, E. DRAGAŠIUS412    VIBROENGINEERING. JOURNAL OF VIBROENGINEERING.   DECEMBER 2010. VOLUME 12, ISSUE 4. ISSN 1392-8716 472  582. Research of the flexible bellow with the          magnetorheological fluid   D. Mažeika1, J. Kunevičius2, V. Volkovas3, E. Dragašius412 bold) 1 Kaunas University of Technology, Kaunas, Lithuania e-mail: 1da.mazeika@stud.ktu.lt; 2justinas.kunevicius@stud.ktu.lt                   3 vitalijus.volkovas@ktu.lt;   4 egidijus.dragasius@ktu.lt  (Received  20 August  2010;  accepted 9 December 2010)     Abstract. MR fluids are widely used in various structures such as controlled dampers, brakes, clutches, etc. Application of these fluids can reduce energy costs and weight as well as increase device operational speed and lifetime. In order to exploit all the qualities of MRS and ERS properties it is necessary to occasionally mix the fluids and monitor them. These systems are still under research and development in laboratories worldwide. This article describes the developed and tested flexible bellow, which can determine whether the MR fluid is under influence of sedimentation and whether it can operate correctly or it is necessary to perform the mixing.  Keywords: magnetorheological fluid, flexible bellow, sedimentation.   Introduction  This article studied flexible bellows with the magnetorheological fluid. Bellows is a tube shaped spring element of the corrugated side surfaces [1]. Its special feature is the large deformations with nearly linear stiffness characteris ic. When Bellows is well-stocked by the rheological fluid, we can be observe MR fluid characteristic and performance when  magnetorheological fluid is left at the rest for some hours and at this time sedimentation process is running. These experiments were carried out by measuring of the two MR fluids then they are exposed to a magnetic field and measuring flexible bellow shift dependence from the current strength of the induction coil.  Flexible bellows  Flexible bellows are used for making linear displacements of force or other factors: pressure, temperature. Therefore, they are often applied for the flow measurement and in control devices for various compensations. Flexible ellows are used in pneumatic and hydraulic gears because they generate large power wh n subjected to high pressure.  Seamless flexible bellows are made from thin-walled pipe, but multi-punched bellows are welded for ring elements (corrugates).  When making high power and compensating bellow construction, we are limited by the strength of the stock assessment. During metrological cases, there is a need to calculate bellow effective area changes in deformation process and to e ermine process deviations from the linear loads. It is also necessary to check bellow stability zones of high strain, thrilling stability and durability of loading cycles [1].    582. RESEARCH OF THE FLEXIBLE BELLOW WITH THE  MAGNETORHEOLOGICAL FLUID. D. MAŽEIKA 1, J. KUNEVIČIUS2, V. VOLKOVAS3, E. DRAGAŠIUS412    VIBROENGINEERING. JOURNAL OF VIBROENGINEERING.   DECEMBER 2010. VOLUME 12, ISSUE 4. ISSN 1392-8716 473   Fig. 1. Geometric parameters of a flexible bellow [1]   Bellow technical parameters   Bellow corrugates can be treated as circular plates, and we can express as symphonic springs stiffness:   ( )nREhrRnAEhcQ23038,4...3,42π≅=        (1)  Here =0RRfAQ – corrugates coefficient; R – outside radius (at the outside corrugates wall center line), mm;  0R  – inside radius (at the inside corrugates wall center line), mm; h – wall thickness, mm; 0h  – inside corrugates deviation from the tube outside, mm.  Bellow corrugates stress is calculated as:   rhFrpππσ2210 =         (2)  The same can be nomographic calculation of stresses: circular 20σ  and bending M1σ  and M2σ .  Bellows are from 4.5 mm to 190 mm in diameter and are suitable for working temperatures between - 260°C to 550°C. The maximum allowable operating environment pressure for bellows is calculated as follows:   ( )2038RRLnkhEpkr+=π         (3)  Bellows may function when they are influenced by transverse and torsional loads.  Then corrugates shear stress is calculated as follows:   582. RESEARCH OF THE FLEXIBLE BELLOW WITH THE  MAGNETORHEOLOGICAL FLUID. D. MAŽEIKA 1, J. KUNEVIČIUS2, V. VOLKOVAS3, E. DRAGAŠIUS412    VIBROENGINEERING. JOURNAL OF VIBROENGINEERING.   DECEMBER 2010. VOLUME 12, ISSUE 4. ISSN 1392-8716 474  Inside 202 RhTv πτ =                   (4) Outside 22 RhkTi πτ =                   (5)  Bellows service life depends on load type and bellow material and is from 8 to 70 thousand cycles. [1]  Research of flexible magnetorheological bellow  The device under study was assembled after producing the necessary components. Fig. 2 illustrates this device that consists of 7 units with 3 of them being standard.      Fig. 2. Image of the device produced by using model constructed with SolidWorks   During assembly of the device from the components, gaps have been filled with a thin layer of sealant. Later, this device was completed with the magnetorheological fluid and attached to the stand (Fig. 3). Induction coil size was chosen on the basis of the flexible bellows outside diameters. Induction coil was made from 0,223 mm wire diameter, coil turns – 900, coil resistance – 46 Ω, coil inductivity – 23 mH. Permissible permanent current 0,40 A, short-term (till  3 seconds) – 1,35 A. Experimental setup (Fig. 3) consists of: Power supply: „V&A Instrument HY3002-2“; Capacitive gap measurement device: „DISA 51D11“; Measurement instrument: Multimeter „Fluke – 87 IV „. In order to accurately measure small displacements we imulated experimental setup using SolidWorks software Experimental setup is adjustable and sufficiently rigid so that measurement accuracy is under insignificant influence. The measuring device operating principle is based on the electromagnetic vibration LCR circuit operating principle. During these measurements the constant are: inductance and resistance parameters (capacity is variable). The capacity was changed by adjusting air gap between sensor plate and the measured surface (Fig. 5). The measured capacity is converted to voltage signal ant it is about U = ± 6V. And because this capacity sensor has a mechanical distance controller, it can be easily calibrated. By measuring the voltage dependence on shift we can easily express MR bellow plate push in micrometers.   582. RESEARCH OF THE FLEXIBLE BELLOW WITH THE  MAGNETORHEOLOGICAL FLUID. D. MAŽEIKA 1, J. KUNEVIČIUS2, V. VOLKOVAS3, E. DRAGAŠIUS412    VIBROENGINEERING. JOURNAL OF VIBROENGINEERING.   DECEMBER 2010. VOLUME 12, ISSUE 4. ISSN 1392-8716 475    Fig. 3. Experimental setup: custom-made adjustable stand, 2. capacitive gap measurement device, 3. reactive impedance converter, 5. induction coil, 6. multimeter, 7. flexible magnetorheological bellow, 8. oscillator   Fig. 4. Experimental setup block diagram    Fig. 5. Air gap between sensor plate and the measured surface of MR bellow Voltmeter Power supply Induction coil MR bellow Capacitance sensor „Disa“ Converter  582. RESEARCH OF THE FLEXIBLE BELLOW WITH THE  MAGNETORHEOLOGICAL FLUID. D. MAŽEIKA 1, J. KUNEVIČIUS2, V. VOLKOVAS3, E. DRAGAŠIUS412    VIBROENGINEERING. JOURNAL OF VIBROENGINEERING.   DECEMBER 2010. VOLUME 12, ISSUE 4. ISSN 1392-8716 476  For the first study we selected magnetorheological fluid MRF-140CG from the “Lord Company“. This fluid has high concentrations of iron particles, approximately 70%, so when the fluid is exposed to a magnetic field it can changed the viscosity characteristics more than other MR fluids with lower concentrations of iron particles. The study was carried in eight days by measuring the deformation of bellow, when the bellow is exposed to a magnetic field.       On the first day the magnetorheological fluid was well mixed and poured into the bellow without air. Next, it was fixed to the experimental setup and the capacity sensor was calibrated. Measured results are provided in Fig. 6.           F(I) = Poslinkis R2 = 0,9973-1,0000,0001,0002,0003,0004,0005,0006,0007,0008,0000 0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9 1I, APoslinkis, µm Fig. 6. Measured MRF-140CG parameters with bellow when MR fluid was perfectly mixed and unaffected by the sedimentation  F(I) = PoslinkisR2 = 0,9973R2 = 0,9929R2 = 0,9909R2 = 0,9704-10123456780 0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9 1I, APoslinkis, µmMRF-140CG_0dMRF-140CG_1dMRF-140CG_2dMRF-140CG_8dLinear (MRF-140CG_0d)Linear (MRF-140CG_1d)Linear (MRF-140CG_2d)Linear (MRF-140CG_8d)  Fig. 7. Measured MRF-140CG parameters with bellow when MR fluid was left from 0 to 192 hours (0 – 8 days) for sedimentation  Fig. 7 presents measured characteristics of the bellow with MRF-140CG. The characteristics indicate that in the sedimentation process the maxium MR fluid particle settling velocity develops at the first 48 hours, after that MR fluid particle settling velocity decreased. This is F(I) = Displacement Displacement, µm F(I) = Displacement Displacement, µm After 0 hours After 24 hours After 48 hours After 192 hours  582. RESEARCH OF THE FLEXIBLE BELLOW WITH THE  MAGNETORHEOLOGICAL FLUID. D. MAŽEIKA 1, J. KUNEVIČIUS2, V. VOLKOVAS3, E. DRAGAŠIUS412    VIBROENGINEERING. JOURNAL OF VIBROENGINEERING.   DECEMBER 2010. VOLUME 12, ISSUE 4. ISSN 1392-8716 477  because the MR fluid consists of many particles of different size, some particles are larger and some are smaller. Larger particles are heavier and more exposed to the gravitational field, so they quickly settle, while smaller particles remain suspended  F(I) = Poslinkis R2 = 0,9526-0,1000,0000,1000,2000,3000,4000,5000,6000 0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9 1I, APoslinkis, µm  Fig. 8. Measured MRF-122EG parameters with bellow when MR fluid was perfectly mixed and unaffected by the sedimentation  During the next investigation stage the bellow was cleaned and washed, subsequently filling it with MRF-122EG fluid. On the first day the magnetorheological fluid was well mixed and poured into the bellow without air. After that it was fixed onto the experimental setup. Measured results are provided in Fig. 8.  After the measurements magnetorheological fluid wasleft at rest for 24 and 48 hours. After the sedimentation process we re-measured bellow deformations. After several days of testing, we noticed deterioration of MRF-122EG fluid performance, because, when operating the same magnetic field for the MR fluid, over time bellow deformation decreased and, after 48 hours of active sedimentation, it essentially stopped. The results are presented in Fig. 9.      F(I) = PoslinkisR2 = 0,9526R2 = 0,9275R2 = 0,7457-0,1000,0000,1000,2000,3000,4000,5000,6000 0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9 1I, APoslinkis, µmMRF-122EG_0dMRF-122EG_1dMRF-122EG_2dLinear (MRF-122EG_0d)Linear (MRF-122EG_1d)Linear (MRF-122EG_2d) Fig. 9. Measured MRF-122EG parameters with bellows when MR fluid was left from 0 to 48 hours (0 – 2 days) for sedimentation  F(I) = Displacement Displacement, µm Displacement, µm F(I) = Displacement After 0 hours After 24 hours After 48 hours  582. RESEARCH OF THE FLEXIBLE BELLOW WITH THE  MAGNETORHEOLOGICAL FLUID. D. MAŽEIKA 1, J. KUNEVIČIUS2, V. VOLKOVAS3, E. DRAGAŠIUS412    VIBROENGINEERING. JOURNAL OF VIBROENGINEERING.   DECEMBER 2010. VOLUME 12, ISSUE 4. ISSN 1392-8716 478  Fig. 9 indicates measured characteristics of the bellow with MRF-122EG. The measured characteristics reveal that in the sedimentation process the maximum MR fluid particle settling velocity develops at the first 48 hours, after that MR fluid particle settling velocity reduces and essentially becomes zero. This is because the MR fluid is made of lower concentration of particles and when particles were exposed to gravity, the sedimentation process proceeds faster because larger MR fluid consists of oil and solid particles settling at least with no interaction with one another, in contrast to higher concentrations MR fluids. After several days of testing with the MRF-140CG and with the MRF-122EG fluids, the measured characteristics were obtained that are given in Fig. 10. Fig. 10 provides measured MRF-140CG and MRF-122EG characteristics. These characteristics demonstrate that at the sedimentatio  process the maximum MR fluid particle settling velocity develops in the first 48 hours, after that MR fluid and particle settling velocity is reduced or in some fluids it essentially drops to zero. It was also noticed that after 48 hours, MRF-122EG fluid was affected by sedimentation process, the MRF-122EG fluid is with a lower concentration of particles and at the higher magnetic field fluid performance is extremely poor and is not adequate for operation, therefore it is necessary to mix the MR fluid.   F(I) = Poslinkis-1,0000,0001,0002,0003,0004,0005,0006,0007,0008,0000 0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9 1I, APoslinkis, µmMRF-122EG_0dMRF-122EG_1dMRF-122EG_2dMRF-140CG_0dMRF-140CG_1dMRF-140CG_2dMRF-140CG_8dLinear (MRF-122EG_0d)Linear (MRF-122EG_1d)Linear (MRF-122EG_2d)Linear (MRF-140CG_0d)Linear (MRF-140CG_1d)Linear (MRF-140CG_2d)Linear (MRF-140CG_8d)  Fig. 10. Measured MRF-140CG and MRF-122EG parameters with bellow when MR fluid was left from 0 to 192 hours (0 – 8 days) for sedimentation  Conclusions  Characteristics of MRF-140CG and MRF-122EG fluid were studied in laboratory conditions by means of the bellow. We also measured the relationship between the fluid particle displacements and generated magnetic field in the electromagnetic coil. Measurement results demonstrate that for MRF-122EG fluid the sedimentation of particles proceeds about 6 times faster than in the case of the MRF-140CG fluid. MRF-140CG fluid particles were made 15 times greater flexible bellow shift at the 1A current of the magnetic field in comparison to the MRF-122EG fluid. Maximum bellow deformation effect was observed when subjecting MRF-122EG fluid particles to a 0,8A current of the magnetic field. F(I) = Displacement Displacement, µm  582. RESEARCH OF THE FLEXIBLE BELLOW WITH THE  MAGNETORHEOLOGICAL FLUID. D. MAŽEIKA 1, J. KUNEVIČIUS2, V. VOLKOVAS3, E. DRAGAŠIUS412    VIBROENGINEERING. JOURNAL OF VIBROENGINEERING.   DECEMBER 2010. VOLUME 12, ISSUE 4. ISSN 1392-8716 479  It was determined that magnetorheological fluid MRF-122EG after 48 hours of sedimentation resulted in extremely poor fluid performance, which is  inadequate for operation purposes, therefore it is necessary to perform mixing of the MR fluid.  References  [1] J. Dulevičius, V. Eidukynas, M. Liutkevičius, L. Naginevičien÷, A. Pavilionis, K. Pilkauskas, S. Žiedelis, P. Žiliukas (2000) Mašinų elementai: skaič avimas ir konstravimas. Kaunas: Technologija. 459p. [2] http://www.lord.com/tabid/3318/Default.aspx [watch date: 2009-10-24] [3] LORD Corporation. http://www.lord.com [watch date: 2009-10-24] [4] http://www.lord.com/Home/MagnetoRheologicalMRFluid/Products/MagnetoRheologicalMRFluids/tabid/3360/Default.aspx [watch date: 2009-10-27] . [5] http://www.lord.com/Default.aspx?tabid=3795 [watch date: 2009-10-27] . [6] http://smart.ippt.gov.pl/adland/ [watch date: 2009-10-27] . [7] www.duke.edu/~hpgavin/papers/seattle01b.pdf [watch date: 2009-10-27] . [8] http://www.iop.org/EJ/article/1742-596/149/1/012045/jpconf9_149_012045.pdf?request-id=ec619fad-3db2-4197-a384-ee266a20e6f8 [watch date: 2009-10-27] . [9] http://www.ieee.org/portal/site/sscs/menuitem.f07ee9 3b2a01d06bb9305765bac26c8/index.jsp?&pName=sscs_level1_article&TheCat=6010&path=sscs/07Fall&file=Gilbert.xml [watch date: 2009-10-15] . [10] http://www.lord.com/Default.aspx?tabid=3795 [watch date: 2009-10-18] . [11]  Jolly, M. R., J.W. Bender and J. D. Carlson, ―Properties and Applications of MR Fluids, SPIE 5th Annual Int. Symposium on Smart Structures and Materials, San Diego, CA, 15 March, 1994.        

Research of the flexible bellow with the magnetorheological fluid

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Research of the flexible bellow with the magnetorheological fluid

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Maintenance, Reliability and Condition Monitoring