The properties of magneto-rheological (MR) materials are temperature dependent. Compared to MR fluids, greases (MRGs) more sensitive due their inherent behavior carrier materials. In this study, MRGs studied examine the effect on yield stress and apparent viscosity. Experimental data obtained for magnetic fields ranging from 0.14 T 0.53 temperatures 10 ° C 70 C. It is observed that has a significant field-induced MRGs. A new model, based an extended Herschel—Bulkley constitutive relation, in...

We present an analysis of the dispersion characteristics and thermal conductivity performance copper-based nanofluids. The copper nanoparticles were prepared using a chemical reduction methodology in presence stabilizing surfactant, oleic acid or cetyl trimethylammonium bromide (CTAB). Nanofluids water as base fluid with nanoparticle concentrations 0.55 1.0 vol.%. A dispersing agent, sodium dodecylbenzene sulfonate (SDBS), subsequent ultrasonication was used to ensure homogenous nanopowders...

We present a study of powder agglomeration and thermal conductivity in copper-based nanofluids. Synthesis the copper powders was achieved by use three different surfactants (polyvinylpyrrolidone, oleic acid, cetyl trimethylammonium bromide). After careful determination morphology purity, we systematically rigorously compared all for production viable nanofluids using dynamic light scattering. Our results show that during synthesis nanopowders has important consequences on dispersion base...

In this study, the response times of magnetorheological fluids and fluid valves are studied under various flow configurations. Two types valving geometries, annular radial flow, considered in valve designs. The transient pressure responses evaluated using a diaphragm pump with constant volume rate. performance each is characterized voltage step input as well current while recording activation electric voltage/current, magnetic flux density, drop function time. variation time rate...

In this research article the contribution of multi-objective stochastical revision a mini unmanned aerial vehicle (i.e., MUAV) having liquid fuel piston-propeller powerplant system via redesigning its automatic flight control AFCS), “fuel weight/total weight” ratio, and propeller pitch for recovering both autonomous performance also general terms maximum range, endurance, ceiling altitude) is investigated. For aim piston-prop MUAV manufactured in Ankara Yıldırım Bayezit University AYBU)...

A novel magnetorheological elastomer (MRE) mount is designed, fabricated, and tested to provide a wide controllable compression static stiffness range for protecting system with variable payload from external shock vibration. The shear dynamic were also studied. MRE field-controllable material in which the properties can be altered by changing applied magnetic field. developed using 0.5-inch thick layers built-in electromagnets. performance of 2-layer characterized compression, shear,...

Abstract A surface grafting technique for poly(2‐fluorostyrene) onto iron particles via atom transfer radical polymerization (ATRP) is described. Grafted poly(2‐fluorostyrene)–iron were synthesized by immobilizing 2‐4(‐chlorosulfonylphenyl)‐ethyltrichlorosilane to the through covalent bond of a silanol group, followed 2‐fluorostyrene monomer. The grafted polymer–iron display higher thermal transition temperature compared bulk polymer because between backbone and restricts molecular mobility....

Current passive elastomeric mounts are designed to provide mitigation for a given shock and vibration exposure not capable of supporting variable payload systems, due variation in the overall system dynamics. A novel magnetorheological elastomer (MRE) mount that can reduce or increase its stiffness based on input is designed, fabricated, tested wide controllable range protecting sensitive systems may require weight from external loading. MRE field-controllable material which properties be...

This paper presents an experimental study on the rheological properties of a magneto-rheological (MR) grease. MR fluids and greases are materials which consist micron-size ferrous particles suspended in carrier fluid. Their material such as apparent viscosity shear stress can be altered dramatically reversibly when stimulated by magnetic field. The main difference between MRG fluid is Unlike fluids, MRGs do not have particle settling issue. steady-shear response with at different...

The goal of this study is to develop a new model describe the behavior shear yield stress magnetorheological greases/gels (MRGs) under combined effects applied magnetic field and temperature. MRGs are class field-responsive materials which consist micron-size ferrous particles suspended in grease/gel-like material. main advantage MRG over MR fluid that MRG, do not settle. However, rheological properties grease carrier very sensitive Therefore, temperature effect on may be one concerns...

Abstract A novel CMRF is synthesized from modified silicone oil, containing composite polyurethane microsphere additives, and surface‐coated iron particles. The designed to act as a liquid spring with controllable damping properties in damper system. fluid compressibility characterized by force/displacement measurements. addition of polyurethane‐microspheres increases the strength fluid. It also decreases concentration particles needed order achieve same yield stress commercially available...

Abstract A novel compressible magnetorheological fluid (CMRF) has been synthesized with additives that provide compressibility to the fluid. This CMRF designed an elastic component a (MRF) can be used as springless damper. provides controllable MRF. The controllability of is achieved by use magnetic particles and external field, made addition suspended polymer particles. characterized force–displacement measurements. off‐state viscosity high shear yield stress. incorporation polymeric into...

This study focuses on the performance of a magneto-rheological (MR) grease damper. MRGs consist micron-sized ferrous particles suspended in carrier material. The main advantage MRG over MR fluid is that do not settle. Experiments are conducted to measure output force response damper under various sinusoidal motion input conditions. test consists frequency sweep maintaining amplitude at constant displacement. In each test, electric current applied prototype kept level 0, 1.0 and 2.0 Amps....

In this study, the fl ow behaviour of Magneto-Rheological (MR) uid through complex valve geometries is investigated using analytical, computational and experimental approaches. A two-dimensional MR model constructed for simulation based on a unique device that has circular, radial annular regions. When compared with analytical solutions, results Computational Fluid Dynamics (CFD) model, which taken into account minor losses in different valving areas, are good agreement those measurements....

The response time of magnetorheological (MR) fluids to an external magnetic field is a few milliseconds. However, the overall in MR devices under function electromagnetic parameters, capabilities driving electronics, as well as, operation conditions. Therefore, device depends on internal design parameters. In this work, times fluid and valves have been studied various flow configurations. Two types valving geometries; annular flow, radial are considered valve designs. transient pressure...

A magnetorheological elastomer (MRE) shock and vibration isolation mount with a semi-active control system was designed, built tested. The stiffness of the MRE can be increased or decreased respect to fail-safe value, based on feedback for effective mitigation. 12.7mm (0.5") thick MREs were specifically formulated achieve static equal legacy replaced. magnetic circuit designed optimized using three-dimensional electromagnetic finite element analysis. algorithm developed that detects...

Dynamic performance of a compressible magnetorheological fluid (CMRF) damper with an asymmetric damping was examined. Due to the 400°F operational environment , high-temperature silicone utilized as base CMRF. The CMRF valve designed and optimized using two-dimensional axisymmetric electromagnetic finite element analysis. A secondary piston that incorporates check valves attached valve, which provides asymmetry under jounce rebound. utilizes twin tube structure, whereas space between inner...