Design and Implementation of Control system for Magneto-rheological damper for vibration reduction in a cantilever beam like structures

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1 ISSN Design and Implementation of Control system for Magneto-rheological damper for vibration reduction in a cantilever beam like structures #1 Shital Rasal, #2 Sharad Kshirsagar 1 rasal_shital@rediffmail.com 2 sharadkshirsagar@gmail.com #1 Student, Mechanical Engineering Department, G. S. Moze College of Engineering Balewadi, Pune #2 Associate Professor, Mechanical Engineering Department, AISSM College of Engineering Shivajinagar, Pune ABSTRACT The analysis and design of control system for Adaptive vibration for cantilever beam like structure is presented in this paper. The control system is implemented via semiactive magneto rheological (MR) damper located on the suspension that links the beam to the ground. Project study is concerned with the Single degree of freedom (SDOF) isolation system with MR fluids damper under harmonic excitation. A mathematical model of the MR fluid damper with experimental verification will be adopted. The motion characteristics of the SDOF system with the MR damper will be studied and compare with those of the system with a conventional damper. The energy dissipated and equivalent damping coefficient of the MR damper in terms of input voltage, displacement amplitude and frequency will be investigated. Keywords Magneto rheological (MR) fluids, Magneto rheological dampers; control system, Carbonyl powder particle; Magnetic field intensity. ARTICLE INFO Article History Received :18 th November 2015 Received in revised form : 19 th November 2015 Accepted : 21 st November, 2015 Published online : 22 nd November 2015 I. INTRODUCTION MR Dampers used commercially in the recent several years are of major interest of researchers. The real time control is the interesting characteristic which leads to spectacular engineering applications. MR dampers are Semi active device controlled by a magnetic field. They contain MR fluid has the property of changes liquid to semi solid state under the application of II. OBJECTIVES OF WORK Experimental setup is developed to implementation of control system for Magneto-rheological damper for vibration reduction in a cantilever beam like structures. The objective of the work is to determine the MR Fluid magnetic field in few milliseconds, so the results is an controllable large damping force in relation with velocity that changes the viscosity of MR fluid. MR damper allows modifying the damping properties under different condition. The MR fluid is representing the non Newtonian fluid, i.e. kinematic viscosity coefficient is variable. Fluid also represents a group of viscous fluids with liquid limit and controlling of their properties. [3] behavior experimentally, and further to find out the control system to reduce the vibration in cantilever type structure. For conducting experiment, MR damper were developed and MR fluid is prepared. To run the total circuit 6 volts DC supply is given to produce current up to 2 A. However the vibration effects were measured and accounted 2015, IERJ All Rights Reserved Page 1

2 III. METHODOLOGY A. Requirement of test facility Test facility was developed by using following parts, 1) Cantilever beam Specifications TABLE III CANTILEVER BEAM SPECIFICATION AND MATERIAL PROPERTIES 2) MR Damper Dimensions/Properties Mild Steel Young s modulus of E 210 MPa cantilever beam Density of cantilever beam ρ 7850 Kg/m3 Thickness of beam t 12 mm Length of beam L 660 mm Width of beam b 25 mm MR damper is similar to the traditional damper except the use of a magneto rheological fluid, which consists of magnetically polarizable particles dispersed in a carrier medium.[7] Under the action of magnetic field, the particle contain in fluid forms chains, and fluid becomes semi solid whish shows plastic behavior and changing the flow properties. MR damper constructed on traditional damper body with Cu Wire 19 Gauge (resistance 1.5 Ω) is wounded on cylinder with 1 spool of 70 cm and 10 layers. Cylinder having ID = 25mm and length 100mm. The piston with four holes on head and damper is 150mm long in its extended position with stroke. The voltage V required to produce the desired damper force f is[12] The power required to control the magnetic field is less than 30 watts, which allow the damper to operate for more than an hour continuously. The magnetic field in the MR damper can be generated with coils wound around the cylinder. The dimension of circular armature is outer diameter DO=50mm, inner diameter DI=28mm, height H=70mm. Maximum current supply is 2 A at normal temperature. Figure 1: Fabricated MR Damper 3) Mechanical Stirrer: This is developed at laboratory for the speed range up to 270rpm variable with dimmer type V2P1 variac (capacity 2A). MR fluids were agitated with mechanical stirrer for 1/2 hours. 4) Universal Vibration Lab:- Universal Vibration lab instrument is manufacture by EEE (P). Ltd. Pune which is available in vibration laboratory. It s a vibration measuring device which measures all type of vibration. As an exciter 180 VDL PMDC motor (1500 rpm) is used which operate on current maximum is 0.4amp range & 60watt B. Instrumentation 1) DC power supply: 6 volts DC supply is required to generate 2A current. At the time of experimentation, Hitech PS 3002 DC power supply is used which have range of 0 to 3v Voltage and current up to 0 to 2A. 2) Rheostat It is used to control current in damper in various steps of 0.5A. The range offered by the rheostat is 5AMPS & 1000 OHMS capacity 3) Input Current measurement: Caddo 51 Multimeter is used to show the exact value of Input current which has range of 200mA to 10A and 200Ω to 2000Ω on armature coil for generate the magnetic field inside the MR Damper. 4) Digital Flux / Gauss Meter Gauss Meter is easily available in physics laboratory which is used to find the magnetic flux in the MR damper manufacture by SECOM. 5) Speed controller: Controlling the speed of DC motor to generate vibration on system having Range ( rpm) 6) FFT Analyser: FFT analyser is SVAN 958 model with four channel make of SVANTEK. Range of the FFT 0.5 Hz to 20 KHz signal analyser including sound level meter and vibration meter. C. Experimental setup:

3 Fig 2: Schematically representation of experimental set up Where, v= speed of piston; f= friction of piston and cylinder; K 0 =coefficient 0.8 to 1.0, h= thickness of the annular fluid between piston and outer cylinder.[11] h = R r If F is much smaller, eq. 1 & 2 can be mathematically manipulated to yield.. (5) Eqn. (3) shows that the damping force developed in the cylindrical MR damper. It can be divided into a magnetic field dependent which is induced yield stress component FY and a viscous component Fɳ. The F Total is the sum of FB and Fɳ. FY = 2πτ B Lr 2, Fɳ = The active volume of MR fluid in the cylinder of MR damper can be evaluated by... (6) v = 2πrLh Electric power consumption of the MR Damper can be find out by... (7) Where, R = resistance, L = inductance, i = current, β = weighting coefficient and J= objective function.[9] V. EXPERIMENTATION Figure 3: complete Experimental setup IV. THEORY CONSIDERATION FOR DESIGN OF FABRICATED MR DAMPER The MR damper design is based on the following criteria s. The mechanical energy required for yielding increases with increase in applied magnetic field intensity which in turn increases yield shear stress. [9] When magnetic field is applied to damper, the shear stress in association with the flow of MR fluid can be predicted by the Bingham equations. τ τ >..(1) Where, τ is the fluid shear stress, is the fluid s yield stress at magnetic flux density B, η is the plastic viscosity (at B=0), and is the fluid shear rate.[1], [11] This equation is used to design any device working with MR fluid. The designed MR dampers working on flow (valve) mode of the fluid. [6], [10]. The total pressure DROP is calculated by ΔP = ΔP η + ΔP Y..(2) Where, ΔP =total pressure drop, ΔP η =viscous pressure loss, ΔP Y =field dependent yield stress pressure loss [11]..(3) Where, η= fluid viscosity, Q =flow rate, L =pole length, w =pole width, g =fluid gap, and τ Y =field yield stress. When magnetic field is applied to damper, the damping force F can be calculated by[11] F damper = P reb (A piston A rod ).P com A piston + frictionsgn(x.) A. MR Fluid Composition & preparation There are basically three components in an MR fluid: basic fluid, metal particles and stabilizing additives. Majority of MR fluid are composed of micron- scale (1-7µm) particles of iron or iron compound mostly Carbonyl Iron powder (CI) suspended in a carrier fluid like Silicone oil, Synthetic oil, mineral oil. [5]The size of particles makes these fluids stable against the settling when not in use. After settled, magnetic attraction between particles makes difficult. The large particles size also could lead to unwanted abrasion & corrosion to components in contact with the fluid. Reduction of the size of magnetic particles in the fluid could eliminate these undesirable effects. MR fluids were composed of mechanically soft ferromagnetic particles. As magnetic material, carbonyl iron (CI) powder (HQ grade) kindly donated by Vimal Intertrade PVT. LTD. was used. The diameter of used carbonyl iron particles was in range μm (D50) and tap density g/cm 3. The powders were characterized for composition, particle size, and shape. Compositional analysis was carried out by X- Ray Diffraction analysis (XRD) as below the peaks corresponding to iron was present in the pattern. CI particles were dispersed with a specific weight fraction (40%) in the SAE 5W 40 oil (Kinematic viscocity = mm 2 /s, dynamic viscosity: CS; density g/cm3). MR fluids were agitated with mechanical stirrer for 1/2 hours... (4) 2015, IERJ All Rights Reserved Page 3

4 Intensity a.u International Engineering Research Journal (IERJ) Special Issue 2 Page , 2015, ISSN Intensity a.u Fe (Fe) 82.38(Fe) Figure 5: Block diagram for open loop control system for MR damper based on input voltage variable to exciter B. Displacement of beam Displacement of cantilever beam can be measured by LVDT or FFT or electronic extensometer Figure 4: XRD result of CI powder B. MR Damper Preparation MR damper were filled by the prepared 35 ml MR Fluid. Circuit diagram connected as per the sequence i.e. DC power supply connected to rheostat. The rheostat connected to multimeter. And it followed to MR damper. Finally negative terminal connected to power supplier. Accelerometer and exciter kept on end of cantilever beam. The flux measurement gauss meter kept near to damper with provision required for the same. C. Control system:- A control system is a system of set of devices, which manage command and regulate the behaviour of other devices or systems to achieve required results. Automatic control system There are two types of Automatic control system - Open control system and closed control system. A control system in which the control action is totally independent of output of the system then it is called open loop control system. Control system in which the output has an effect on the input quantity in such a manner that the input quantity will adjust itself based on the output generated is called closed loop control system. The main feature of control system is there should be a clear mathematical relation between input and output of the system. If output and input of the system shows linear proportional relation called linear system and if there is no single linear relation is called non linear system MR damper control system:- This control system is shows linear relation between three parameters - Input Voltage to motor used as exciter, Displacement of beam, Speed of motor in rpm. These three parameters are used to design the control system for MR Damper for vibration reduction for cantilever type structure.[13, 14] A. Input Voltage to motor used as exciter Input Voltage to motor used as exciter can be measured by multimeter or CRO (in the form of wave form). Figure 6: Block diagram for open loop control system for MR damper based on displacement of cantilever beam C. Speed of motor in rpm Speed of motor used as exciter can be measured by Tachometer or stroboscope or proximity sensor. Figure 7: Block diagram for open loop control system for MR damper based on input speed of exciter motor VI. RESULTS AND DISCUSSION A. Gauss meter result: There is linear relation between current and magnetic flux intensity. When the current supplied to MR damper increases the magnetic flux also increases TABLE III GAUSS METER READINGS FOR DIFFERENT CURRENT LEVEL Current in Ampere Gauss meter reading in Gauss B. Sedimentation Result:- The sedimentation of CI powder in Carrier Fluid was measured by visual observation. Prepared samples (70 ml) were placed into measuring cylinder of 100ml for a 90 min. As a result sedimentation ratio (R) was calculated by (1) 2015, IERJ All Rights Reserved Page 4

5 Where: R (%) - sedimentation ratio, p length of the clear part, q length of the turbid part.[2] Stability of MR fluid depends on the CI content & Stabilization agent like Arsil 1100, Aerosil 200 and 972 & dispersion agent like Lecithin.[2], [4] The stabilization agent depends on carrier medium. Normally, higher content of CI increase the stability. Due to lower quantity of oil required in damper (35ml), the stabilizing agent is not used. As can be seen on Figure 7, the stability of the 40 % loaded MR fluid was much better than the 10, 20, and 30 % loaded one. Stabilizers Aerosil 200 with 1% amount of grew good stability for large quantity carrier fluid & 40% CI. Doubling the Aerosil 200 content in decreased the sedimentation ratio. Current supplied 2.0A D. Input readings for control system based on variable voltage to exciter The graph of input Voltage to motor vs Speed of the exciter shows linear relationship y = 0.090x Which have Coefficient of determination is R² = This relationship is used to design the control system. Fig. 8 Sedimentation Ratio VS Time for MR fluid with different CI content C. Effect of vibration with and without use of MR damper The graph shows effect of amplitude of vibration without use of any damper, with viscous damper and at variable input current. As the supplied current increases the velocity decreases at frequency Hz Figure 10: variable Voltage supplied to the exciter VII. PROPOSED WORK On the above results, control system will be design. And further it analysis and implementation will be done. The microcontroller, PID or PI controller can be used to control the system. The programming for the microcontroller can be done in MATLB or C++. [13] [14] VIII. CONCLUSIONS Fig. 9 effect on velocity when cantilever beam vibrate without damper, with viscous damper and TABLE IIIII DIFFERENT VALUES OF VELOCITY FOR DIFFERENT CONDITIONS Condition for Velocity in mm/s Cantilever beam at Hz without damper with Viscous damper Current supplied 0.5A Current supplied 1.0A Current supplied 1.5A a. Magneto rheological fluid composed of CI particles and SAE oil as carrier fluid were prepared for suspension system. The stability of fluid was improved by formulation and stirring time with additives. b. The result presented in this paper show the good effectiveness of MR damping within the full range of excitation frequency occur in cantilever type structure. The tendency vibration reduction of the active system s is highly effective than the passive system at the time of resonance frequency. c. The design parameters of the MR damper are derived. The equivalent damping coefficient of the MR damper in terms of input current and voltage, magnetic flux, velocity and frequency are investigated. d. The SDOF isolation system with and without MR damper quantified and compared in terms of velocity. ACKNOWLEDGMENT The first Author would like to thank Mr. Nirav Shah Vimal Intertrade PVT. LTD. for kindly provided carbonyl iron sample. The support of Dr M. L. Kulkarni & Prof. N. S. Sarpe Department of Mechanical Engineering JSPM Narhe Technical Campus and Prof. R. D. Wategaonkar Department 2015, IERJ All Rights Reserved Page 5

6 of Automobile Engineering Rajendra Mane college of Engineering is acknowledged. REFERENCES [1] M. Kciuk and R. Turczyn, Properties and application of magnetorhelogical fluids, Journal of Achievements in Materials and Manufacturing Engineering, Volume 18 (2006) [2] R. Turczyn and M. Kciuk Preparation and study of model magnetorheological fluids, Journal of Achievements in Materials and Manufacturing Engineering, Volume 27 (2008) [3] S. Kciuk and R. Turczyn, M. Kciuk Experimental and numerical studies of MR damper with prototype magnetorheological fluid, Journal of Achievements in Materials and Manufacturing Engineering, Volume 39 (2010) [4] Nicholas Rosenfeld and Rdhakumar Radhakrishnan et.al. Behavour of Magnetorhehologicalfluid utilizing nanopowder iron International Journal of Modern Physics B, Vol.16, Nos. 17 & 18 (2002) [5] J. L. Arias et.al., Preparation and characterisation of carbonyl iron/poly (butylcyanoacrylate) core /shell nanoparticles, Journal of collid and Interface Science 299 (2006) [6] A. Spaggiri, Properties and applications of Magnetorheological fluids, Frattura ed Integrita Strutturale, 23 (2013)57-61 [7] New Product and Technologes, JFE Technical Report No.6 (2005) [8] Joseph E. Japka, Microstructural and properties of Carbonyl Iron Powder:,Journal of Metals (1988)18-19 [9] Vijay Tripathi, U. K. Joshi, Experimental Analysis of Fabricated Magnetorheological Damper, International Journal Of Science, Engineering And Technology, Volume 02 Issue 04 April-May 2014 [10] J Wang, G Meng, Magneto rheological fluid devices: Principles, characteristics and applications in mechanical engineering, Proc Instn Mech Engrs Vol 215 part I(2001) [11] Mark R. Jolly et. al, Properties and applications of commercial Magneto rheological fluids [12] Henri Gavin et al, Optimal design of MR dampers, US Japan Workshop on smart structures for improved seismic performance in urban regions pp (2001) [13] Bogdan Sapinski, Magneto rhehological dampers in vibration control of mechanical structures, Mechanics Vol.28 No. 1 (2009) [14] Tomoaki Mori, et al, Adaptive Semiactive control of suspension system, IFAC (2007) 2015, IERJ All Rights Reserved Page 6