Fabrication & Characterization of MR Nanocomposites based on Silicone Rubber (original) (raw)
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IJISME
This paper presents a comparative study on mechanical and magnetic properties of two sets, each including five samples of film-shaped magnetorheological nanocomposites (MRNCs) based on RTV silicone rubber and nano-sized carbonyl iron particles (CIPs). One set of sample was prepared by polymerization of silicone rubber with CIPs and silicone oil, while the other set obtained by filling the ammonium bicarbonate (NH4HCO3), CIPs and silicone oils. Both set of samples were manufactured under isotropic condition and their microstructures was characterized by XRD and EFSEM. Porosity characteristics was measured by displacement method and porosity image analysis was applied using ImageJ and Origin Pro Software. The mechanical tensile tests was conducted using Gotech tensile strength tester and the density of samples was observed experimentally and estimated theoretically. The magnetic properties of MRNCs were practically determined using VSM test. Plateau stress induced by the applied magnetics fields and MR effects was determined. Through fabrication of film-shaped MRNCs, the samples deflections was measured against applied magnetic fields .The comparative investigation results show that porosity improve the mechanical and magnetic properties of MRNCs and porous MRNCs will be the good candidate for miniature and flexible gripper’s jaws.
MREs Development and Its Application on Miniature Gripper
ipcsit.net
Smart composites based on carbonyl-iron particles in a silicone rubber known as magneto-rheological Elastomer (MREs) whose modulus can be controlled by strength of magnetic fields. In this article, MRE materials based on silicon rubber matrix are fabricated without applying magnetic field. The mechanical properties and SEM images are investigated. MRE samples were fabricated by two-component silicone rubber with 50 % content of 10 μm sized carbonyl-iron particles by volume. In the course of material development, samples of carbonyl-iron filled by silicone rubber are produced and their mechanical and magnetic properties are practically determined. The developed MRE samples are placed in the magnetic field that varied from 0 to 100 kA/m. The observations of samples in the presence and absence of the magnetic field show that the magnetic field increased the stiffness of the material. Additionally, the rheological properties of MREs are tested in a magnetic field. Through successful development of Magneto Rheological Elastomer, the produced MRE is used in its potential applications for a miniature gripper. Using the developed MRE, a miniature gripper is designed and fabricated. Developments of MREs along with design methodology of grippers enhance performance of micro-mechatronics system used in medical and metrological devices as well.
Journal of Central South University, 2015
The preparation of natural rubber based isotropic thick magnetorheological elastomers (MRE) was focused on by varying the percentage volume concentration of carbonyl iron powder and developing a test set up to test the dynamic properties. Effect of magnetic field on the damping ratio was studied on the amplification region of the transmissibility curve. The viscoelastic dynamic damping nature of the elastomer was also studied by analyzing the force-displacement hysteresis graphs. The results show that MR effect increases with the increase in magnetic field as well as carbonyl iron powder particle concentration. It is observed that softer matrix material produces more MR effect. A maximum of 125% improvement in the loss factor is observed for the MRE with 25% carbonyl iron volume concentration. FEMM simulation shows that as carbonyl iron particle distribution becomes denser, MR effect is improved. FEMM analysis also reveals that if the distance between the adjacent iron particles are reduced from 20 μm to 10 μm, a 40% increase in stored energy is observed.
Modares Mechanical Engineering
This paper deals with the design and fabrication of an adjustable, two fingers flexible miniature gripper based on porous magnetorheological nanocomposites having the adjustability of pre-openings of the jaw’s tips and its operational study in according to the performance. The fabricated gripper holds the small size and lightweight objects, maintain them and release them as required upon reducing the electrical current. The magnetic analysis has done and magnetic simulation has conducted using Vizimag software. The lead, condensed papers, foams and silicon wafer sheets were used as under experiments materials and it has been noticed that it is working properly to grip the things which has rough surfaces at all. For a greater objects, it can be adjusted through its tips as well. In this scheme, the magnetic actuation has been used because the magnetorheological nanocomposites is the most sensitive materials against the magnetic field. This type of grippers includes the simple montage, lower fabrication prices and owns lower volume as well as weight, and there will be no need to apply the classic mechanical linkage inside. This type of grippers are recommended for applications in the fields of the micro electromechanical systems, especially in the holding and transporting of sensitive work pieces against scratches, fingerprints and pressure.
Solid State Phenomena, 2012
Results on anisotropic magnetorheological elastomers' magnetoelasticity are presented and discussed. In the dipole approximation, and considering the MRE as a continuous linear body, the effects of magnetic field on its main elastic properties (linear deformations and Young module) are investigated. Experimental evidences that the compression of the cylindrical bar is influenced by the intensity of the longitudinal magnetic field and the Young module of the MRE sample increases with the intensity H of the longitudinal magnetic field are obtained and the results discussed.
Dynamic properties of magnetorheological elastomers based on iron sand and natural rubber
Journal of Applied Polymer Science, 2014
In this study, magnetorheological elastomers (MREs) based on iron sand and natural rubber were prepared. The Taguchi method was employed to investigate the effect of a number of factors, namely, iron sand content, iron sand particle size and applied magnetic field during curing on tan δ and energy dissipated during cyclic loading. Tan δ was measured through dynamic mechanical analysis (DMA) over a range of frequency (0.01-130Hz), strain amplitude (0.1-4.5%), and temperature (-100-50 °C). Energy dissipated was measured using a universal tester under cyclic tensile loading. The data were then statistically analysed to predict the optimal combination of factors and finally experiments were conducted for verification. It was found that the iron sand content had the greatest influence on tan δ when measured over a range of frequency as well as energy dissipated during hysteresis tests. However, none of the factors showed significant influence on tan δ when measured over a range of strain amplitude. Furthermore, the iron sand content and magnetic field were also found to influence the width of the peak in tan δ as a function of temperature. The morphological characteristics of the MREs were also examined using scanning electron microscopy (SEM).
Development and Characterization of Isotropic Magnetorheological Elastomer
Universal Journal of Mechanical Engineering, 2013
Magneto rheological elastomer (MRE) is a new kind of smart materials. Its dynamic mechanical performances can be controlled by controlling an applied magnetic field. MRE is usually used as stiffness-changeable spring in the semi-active vibration absorber. In order to get perfect vibration control effect, low dynamic damping of MRE is needed. This paper presents a new method of fabricating isotropic MREs under normal temperature and pressure conditions. In the absence of a magnetic field, a variety of MR elastomer samples were prepared using Sylard's184 silicone elastomer along with un-annealed electrolytic iron power 500 mesh and 15 micron size. Their dynamic characteristics like fractional change in resonant frequency and fractional change in have been studied. The effects of iron particles and the applied magnetic field were investigated. This study is also expected to provide a good guide for designing and preparing new MR elastomers.
Characterization of Magneto-Rheological Elastomer and Modelling of MRE Based Isolators
2018
Magneto rheological elastomer (MRE) is a new kind of smart material whose dynamic properties can be altered in the real time with an externally applied magnetic field. This advantage of MRE has brought up its application to the development of real time adaptable base isolation systems, with ability to change the stiffness and damping according to applied magnetic field. The MRE base isolator generally consist of a laminated layer of MR elastomer sheets and steel sheets, sandwiched between two thick steel plates one at top and other at bottom, and enclosed by a current carrying coil. Current in the coil generates magnetic field which alter the stiffness and damping of the isolator and by controlling the current, the required stiffness and damping can be achieved. In this study, characterization and modelling of the current dependent visco-elastic properties of synthetic rubber based MRE is carried out. Synthetic rubber based MRE were fabricated with magneto-sensitive carbonyl iron (C...
Defence Science Journal
Magnetorheological Elastomers (MRE) endure a change in mechanical properties with the application of an externally applied magnetic field. It consists of an elastomeric matrix reinforced with ferromagnetic powdered particles. This paper focuses on the investigation of viscoelastic properties of Room Temperature Vulcanized (RTV) silicone based isotropic MRE in sandwich beam configuration by varying the volume percentage of Carbonyl Iron Powdered (CIP) reinforcement. Viscoelastic properties of the MRE core material were calculated by following the ASTM E756-05 standard. The magnetic field was applied by employing a Halbach array which was numerically analyzed using Finite Element Method Magnetics (FEMM). The magnetic field was varied up to 0.15 T. Loss factor and shear modulus were found to be strongly influenced by the percentage content of CIP. The loss factor and shear modulus of 30% MRE at 0.15 T were higher than other tested samples. The variation of natural frequency with respec...