Issue 32

N. Golinelli et alii, Frattura ed Integrità Strutturale, 32 (2015) 13-23; DOI: 10.3221/IGF-ESIS.32.02 22 The end-plug and the bottom-rod were glued to the cylinder using an acrylic adhesive (LOCTITE 638). The MR fluid was poured through the welded boss into the cylinder. To eliminate the air into the damper, the system was placed in a vacuum chamber. Then, two ball joint ends were screwed to the rod and the end plug (Fig. 12). Figure 12 : Final assembled prototype. C ONCLUSION his work shows a design method for a magnetorheological damper with pressure control. By means of analytical equations the magnetic circuit and the hydraulic circuit have been designed. The new MR damper has an innovative architecture able to drive the internal pressure level. A bottom-rod has been adopted which has the same diameter of the upper rod. The main consequence is that the internal volume of the damper remains constant during the operation and an accumulator is no more needed. In order to increase the feasibility of the prototype, commercial components were used: a hydraulic cylinder, its cylinder head and two ball joint ends. Instead, the piston rod, the piston head and the bottom rod were designed and manufactured. Finally, all components were assembled paying particular attention to the concentricity between the cylinder, the piston head and the bottom rod. A conceptual design of pressurization system has also been presented. Such system consists of a screw drive mechanism that controls the stroke of a slider. Moving the slider leads to control the internal volume of the damper and consequently changes the internal pressure. To our best knowledge the prototype presented is the first of its kind ever realized. Several tests will be carried out to test the behavior of this device. The results might bring up new considerations that could lead to an optimization of the properties of the damper and to its commercialization. B IBLIOGRAPHY [1] Kaluvan, S., Choi, S.-B., Design of current sensor using a magnetorheological fluid in shear mode, Smart Mater. Struct., 23(12) (2014) 127003. [2] Alkan, M. S., Gurocak, H., Gonenc, B., Linear magnetorheological brake with serpentine flux path as a high force and low off-state friction actuator for haptics, J. Intell. Mater. Syst. Struct., 24(14) (2013) 1699–1713. [3] Yadmellat, P., Kermani, M. R., Adaptive modeling of a magnetorheological clutch, IEEE/ASME Trans. Mechatronics, 19(5) (2014) 1716–1723. [4] Zhu, X., Jing, X., Cheng, L., Magnetorheological fluid dampers: A review on structure design and analysis, J. Intell. Mater. Syst. Struct., 23(8) (2012) 839–873. [5] Fuchs, A., Rashid, A., Liu, Y., Kavlicoglu, B., Sahin, H., Gordaninejad, F., Compressible magnetorheological fluids, J. Appl. Polym. Sci., 115(6) (2010) 3348–3356. [6] Spaggiari, A., Dragoni, E., Effect of internal pressure on flow properties of magnetorheological fluids, in: ASME 2011 Conference on Smart Materials, Adaptive Structures and Intelligent Systems, 1 (2011) 7–15. [7] Spaggiari, A., Dragoni, E., Effect of pressure on the physical properties of magnetorheological fluids, Fract. Struct. Integr., 23 (2012) 75–86. [8] Spaggiari, A., Dragoni, E., Combined squeeze-shear properties of magnetorheological fluids: effect of pressure, J. Intell. Mater. Syst. Struct., 25(9) (2013) 1041–1053. T