 Proceedings of Engineering and Technology Innovation, vol. 7, 2017, pp. 14 - 19 Study of Alloy Springs with Magnetorheological Dampers for Vibration Isolator Device Dyi-Cheng Chen * , Li-Ren Chen Department of Industrial Education and Technology, National Changhua University of Education, Changhua 500, Taiwan. Received 16 July 2017; received in revised form 19 August 2017; accept ed 30 August 2017 Abstract Vibrat ion is a factor that must be controlled during the manufacturing process; variation in workpiece dime n- sions often results in inaccuracies due to v ibration. This study adopted a spring and electro magnetic -repulsion and magnetorheological da mper that can absorb the energy of e xte rnal vibrat ions and deduced the influential vibrat ion factors. ANSYS was e mp loyed to determine the energy that could be absorbed by the vibration isolation device under mach ine vibrat ion, and the Taguchi method of quality engineering was used to design the structure of the device (metal spring, wire dia meter, and materia l). The usabil ity of the product was e xa mined for applicat ion in computer nume rica l control and tradit ional machines. The considered parameters of the magnetorheological fluid were density, coefficient of elasticity, and Poisson’s ratio. The results indicated that sprin g wire dia meter e xerted the strongest effect on the device’s performance and that the electrical current provided to the damper could be buffered . Keywor ds : vibration isolation device, alloy spring s, magnetorheological dampers 1. Introduction Serving as a semiactive control element, a magnetorheological (MR) damper is a smart damping device that is controlled by a magnetic field [1]. An MR damper with semiactive control integrated with the controllability and flexibility of active dampin g can adjust its damping force in response to load force and structure and is characterized by passive stability and energy conservation. The dynamics of an MR damper under different input voltages [2] enable the input voltage to pass through a current driver, which generates an electric current. The electric current then passes through a coil to generate a magnetic field; adjusting the input voltage thus changes the magnetic field strength. Kim et al. [3] proposed an innovative friction pendulum system and MR damper that utilize the isolator and auxiliary damper of a smart base isolation system. A fuzzy logic controller is generally used to regulate an MR damper because it has inherent robustness and its capability in processing nonlinear and uncertainty data. Beijen et al. [4] demonstrated that a control scheme with two sensors was superior that with sensor fusion because cyclic shaping and greater stability are possible. Van der Sandea et al. [5] proposed that by changing the weighting filter, different controllers could be d esigned to emphasize comfort or controllability. 2. Research Methods 2.1. Simulation analysis of the organization SolidWorks was used to design the vibration isolation device and mechanism shown in Fig . 5. The overall design concept of the mechanism is displayed in Figs . 1 and 2. During an earthquake, the springs absorb vibration. Because earthquake movement can occur in various directions—for example, horizontal or vertical—this mechanism was designed to enable absorption regardless of the direc- tion of movement. * Corresponding author. Email address: dcchen@cc.ncue.edu.tw Proceedings of Engineering and Technology Innovation, vol. 7, 2017, pp. 14 - 19 Copyright © TAETI 15 Fig. 1 Vibration isolation device 2.2. ANSYS ANSYS is a fin ite ele ment analysis software package; its processing operations can be divided into a preprocessor, postprocessor, and solver. The postprocessor module d isplays calculated results using graphical methods such as a color contour, gradient, vector, part icle trac k, three-dimensional section, transparent, and semit ransparent displays. Ca lculated results can be displayed or output in the forms of charts or curves . 2.3. Taguchi quality engineering The offline quality control of Taguchi e mploys three -stage quality engineering design to achieve a robust product. In the first stage, which is system design, engineering personnel determine the ideal product design concepts according to their professional knowledge, e xperience, and mutual discussion. In the second stage, parameter design, re levant process parameters are selected and an orthogonal arrange ment is used to conduct an experiment, the purpose of the orthogonal arrangement is to reduce the sensitivity of the product toward interference by noise and thus reduce variation in product quality. The third st age, tolerance design, focuses on process operating conditions and analyzes causes of p roduct variation to determine the product’s tolerance range. The loss function can be used to calculate product cost after the tolerance design stage. Loss functions are used in quality engineering to obtain a balance between cost and quality. This researc h project e mployed an orthogonal array (OA) to plan the e xpe riment. The response table and factor effect diagra m we re used to determine the effect of each factor on a ta rget value and then to select the most favorable parameter combination . 3. Results of Research and Analysis 3.1. The setting of magnetorheological fluid Prior to simu lation analysis, the para meters of the MR fluid (MRF) had to be set, including its density, coeffic ient of elasticity, and Po isson’s ratio. The Poisson’s ratio of a fluid is 0.5. In consideration of the changes to the MRF under di f- ferent magnetic currents, the Poisson’s ratio of the MRF was set at that of rubber (i.e., 0.45). The density of magnetorheological fluids is known fro m the description of Lo rd's magnetorheological da mper products. The elastic modu lus of the para mete rs set for the magnetorheological fluid is required to co mple x modulus G * , the modu lus of the modulus of the material show the relationship between the stress -strain ratio, the modulus of the complex modulus G * G * = G' + iG" (1) G ' is Young's coeffic ient of storage modulus, and the viscoelastic materia l by the vibrat ion of the storage energy elastic part. G "for the loss modulus is the viscoelastic materia l by the vibration force when the part of the energy consumption. Sun et al. [6] obtained e xperimental data to obtain a set of non -linear re lationship between the modulus and loss modulus of the magnetorheological material and the magnetic field : damper spring MRF Proceedings of Engineering and Technology Innovation, vol. 7, 2017, pp. 14 - 19 Copyright © TAETI 16 G' =3.11X10 -7 B 2 + 3.56 X10 -4 B + 5.78X10 -1 (2) G" =3.47X10 -9 B 2 + 3.85 X10 -6 B + 6.31 X10 -3 (3) B is the magnetic induction intensity, unit mT. Diffe rent magnetic fie lds result in diffe rent magnetic induction intensities, as illustrated in Fig. 15. The magnetic indu c- tion intensity was substituted into (1) to obtain the complex modulus G*, which is detailed in Table 1. Table 1 MRF-140CG magnetorheological damper parameters current M agnetic induction (mT) G'(M Pa) G"(M Pa) G * (M Pa) 0 0 0.578 0.006 0.578+0.006i 0.5 350 0.74 0.008 0.74+0.008i 1 550 0.867 0.009 0.867+0.009i 3.2. The setting of magnetorheological fluid Table 2 d isplays the settings of various materia l para meters. The force e xe rted above the shock absorber mechanis m during each simu lation was 5000 N; pressure was applied downward, and the total deformat ion and von Mises stress were determined. Table 2 Material parameters table material Al JIS G 3522 Si-Cr Alloy SUS316 M RF-140CG density (g/cm 3 ) 2.7 7.85 7.86 8.02 3.64 Young's modulus (M Pa) 69000 205882 207000 186274 1.03 Poisson's ratio 0.34 0.3 0.3 0.3 0.45 3.3. Application of Taguchi method to be optimized This study select four spring factors and one MRF factor for the vibration isolation device (Table 3). Tab le 4 lists the L27(3 5 ) OA co mprising the total deformat ion and von Mises stress obtained through 27 simulat ions with various parameter values. Table 3 Earthquake device mechanism parameter factor A B C D E Factor Wire diameter (mm) Sp ring center diameter (mm) Sp ace(mm) Sp ring material Current(A) Level 1 6 50 20 JIS G 3522 0 Level 2 8 60 25 Si-Cr Alloy 0.5 Level 3 10 70 30 SUS316 1 Table 4 L 27(35) Proceedings of Engineering and Technology Innovation, vol. 7, 2017, pp. 14 - 19 Copyright © TAETI 17 As shown in Tables 5 and 6, the most favorable parameters obtained for four factors at three levels were a spring wire dia meter of 6 mm (A 1), spring center dia meter of 60 mm (B2), spring coil spacing of 25 mm (C2), spring material of chro me silicon (D2), and damper current of 0 A (E). Regarding the degree of impo rtance to the vibration isolation mechanism, the parameters were in a descending order of spring wire dia meter > spring ma teria l > spring coil spacing > spring center diameter > damper current. Fig. 3 plots the S/N (smaller) factor response of the total deformation. Table 5 Total Deformation S / N ratio factor reaction Level A B C D E 1 20.34 16.52 16.41 16.70 17.60 2 16.41 19.57 19.68 19.89 17.60 3 16.04 16.71 16.71 16.21 17.60 Delta 4.30 3.05 3.27 3.68 0.00 Rank 1 4 3 2 5 Table 6 Total Deformation of the best parameters A1 B2 C2 D2 E Wire diameter (mm) sp ring center diameter (mm) Sp ace(mm) Sp ring material Current(A) 6 60 25 Si-Cr Alloy 0 The most favorable obtained para meters were used to construct a model, and A NSYS analysis was perfo rmed to obtain the following results: greatest total deformation of 0.169 mm (Fig. 4 (a)) and greatest von Mises stress of 97.12 M Pa ( Fig. 4 (b)). As shown in Tables 7 and 8, the most favorable para meters obtained for the four factors at the three levels we re a spring wire dia meter of 10 mm (A3), spring center diameter of 50 mm (B1), spring coil spacing of 20 mm (C1), spring material of SUS316 (D3), and damper current of 0 A (E). The para meters had the follo wing order o f importance in their effect on the vibration isolation mechanis m: spring center dia meter > spring wire d ia meter > spring coil spacing > spring materia l > da mper current. Fig. 5 shows the S/N (smaller) factor response diagram of von Mises stress. Table 7 von Mises S / N ratio factor reaction Level A B C D E 1 -39.78 -39.65 -39.71 -41.87 -40.45 2 -41.90 -42.00 -39.76 -39.75 -40.45 3 -39.66 -39.69 -41.87 -39.72 -40.45 Delta 2.24 2.35 2.16 2.15 0.00 Rank 2 1 3 4 5 Table 8 Von Mises of the best parameters A3 B1 C1 D3 E Wire diameter (mm) sp ring center diameter (mm) Sp ace(mm) Sp ring material Current(A) 10 50 20 SUS316 0 The most favorable obtained para meters we re used to construct a model, and ANSYS analysis was perfo rmed to dete r- mine the greatest total deformation of 0.166 m (Fig. 6 (a)) and greatest von Mises stress of 97.38 GPa (Fig. 6(b)) . 4. Conclusions In this study, the investigated MRF was treated simila r to a solid to configure the material para meters. During the simu- lation process, these parameters we re simp lified by overlooking viscosity. Optimal values of total deformation and von Mises stress were obtained through simulat ion analysis followed by Taguchi analys is. Quality characteristics were selected based on the smalle r the better situation to minimize product variation. The optimal para meter results obtained through simu lation analysis revealed that spring wire dia meter had the most crucia l e ffect on the performance of the vibrat ion isolation mechanism; increasing the spring wire dia meter would increase the seismic performance of the mechanism. Proper selection of the spring center dia meter and spring coil spacing also enhances seismic perfo rmance. The results of this study can serve as a useful reference for relevant industry. Proceedings of Engineering and Technology Innovation, vol. 7, 2017, pp. 14 - 19 Copyright © TAETI 18 Fig. 2 MRF-140CG magnetorheological damper magnetic field and magnetic induction change map Fig. 3 Total deformation S / N ratio calculation (a) Total deformation (b) Von Mises stress Fig. 4 Total deformation model and von Mises stress Fig. 5 Von Mises stress S / N ratio calculation Proceedings of Engineering and Technology Innovation, vol. 7, 2017, pp. 14 - 19 Copyright © TAETI 19 (a) Total deformation (b) Von Mises stress Fig. 6 Total deformation model and von Mises stress References [1] S. Narasimhan, S. Nagarajaiah, and E. A. Johnson, “Smart base-isolated benchmark building part IV: Phase II sample controllers for nonlinear isolation systems,” Structural Control and Health Monitoring. vol. 15, no. 5, pp. 657-672, July 2008. [2] S. J. Dyke, B. F. Spencer Jr., M. K. Sain, and J. D. Carlsonl, “Modeling and control of magnetorheological dampers for seismic response reduction,” Smart Materials and Structures, vol. 5, no. 5, pp. 565-575, 1996. [3] H. S. Kim and P. N. Roschke, “Design of fu zzy logic controlle r fo r sma rt base isolation system using genetic algorith m,” Engineering Structures , vol. 28, no. 1, pp. 84-96, January 2006 [4] M. A. Beijen, D. Tjepkema, and J. van Dijka, “Two-sensor control in active vibration isolation using hard mounts ,” Control Engineering Practice, vol. 26, pp. 82-90, May 2014. [5] T. P. J. van der Sandea, B. L. J. Gysenb, I. J. M. Besselinka, J. J. H. Paulides , E. A. Lo monova , and H. Nijmeijer, “Robust control of an e lectro magnetic active suspension system: Simulat ions and measureme nts,” Mechatronics, vol. 23, no. 2, pp. 204-212, May 2013. [6] Q. Sun, J. X. Zhou, and L. Zhang, “An adaptive bea m model and dynamic characteristics of magnetorheological materia ls ,” Journal of Sound and Vibration, vol. 261, no. 3, pp. 465-481, March 2003.