Magnetorheological fluid

About: Magnetorheological fluid is a research topic. Over the lifetime, 8538 publications have been published within this topic receiving 131502 citations. The topic is also known as: MRF & MR fluid.

Magnetorheological fluid durability test: Iron analysis

Abstract: This report describes chemical changes and the methodology to detect such changes in iron particles from extracts of certain magnetorheological fluids (MRFs) which had been subjected to durability testing in an MRF fan clutch. Samples of MRF subjected to 540 and 108 h of service in a MRF fan clutch on a test stand were characterized along with neat and unused materials for comparison. The results indicated that: the iron subjected to durability testing had oxidized; a portion of the iron oxides were crystalline magnetite; and the oxides were concentrated at the perimeter of the smaller iron particles although both large and small particles were oxidized. This oxidation may explain the gradual loss of fan clutch torque capacity observed during the 540 h durability test.

A review on parametric dynamic models of magnetorheological dampers and their characterization methods

Abstract: Magnetorheological (MR) fluids are capable of manifesting a rheological behaviour change by means of a magnetic field application and can be employed in many complex systems in many technical fields. One successful example is their use in the development of dampers: magnetorheological dampers (MRDs) are widespread in vibration control systems, as well as civil engineering applications (i.e., earthquake or seismic protection), impact absorption and vibration isolation technology in industrial engineering, and advanced prosthetics in biomedical fields. In the past, many studies have been conducted on MRDs modeling and characterization, but they have usually been focused more on the theoretical models than on the experimental issues. In this work, an overview of both of them is proposed. In particular, after an introduction to the physics of the magnetorheological effect, a short review of the main mathematical models of MRDs is proposed. Finally, in the second part of this study an overview of the main issues that occur in MRDs experimental characterization is reported and discussed.

Performance tests and mathematical model considering magnetic saturation for magnetorheological damper

Abstract: As a semiactive control device, magnetorheological dampers have been paid more attention due to their high controllability, fast response, and low power demand. One of the important characteristics...

Hood assembly utilizing active materials based mechanisms

Abstract: An active material hood impact mitigation mechanism is activated in response to a signal generated from an impact sensor or pre-impact sensor or manually. The mitigation mechanism is capable of changing either reversibly or irreversibly the stiffness, shape, location, orientation, or displacement force of the hood either globally or locally, before an impact against the hood. The active material mitigation mechanism is held in a device designed to be installed in operative communication with the hood surface. The active material is characterized by a first shape or stiffness and is operative to change to a second shape or stiffness in response to the activation signal. Such active materials include shape memory alloys, electroactive polymers, shape memory polymers, magnetic shape memory alloys, magnetorheological fluids, magnetorheological elastomers, electrorheological fluids, and piezoelectric materials.