Wyniki 1-1 spośród 1 dla zapytania: authorDesc:"Paweł TRĘBACZ"

Prototyping an MR damper system DOI:10.15199/48.2018.11.34

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Flow-mode magnetorheological (MR) shock absorbers are exemplary semi-active devices utilizing so-called MR fluids. The fluid is a colloidal suspension of micron-size soft ferromagnetic particles [1]. The material when exposed to magnetic filed develops a yield stress, thus undergoing a transition from a liquid to a pseudo-solid. The particles that are suspended in the carrier oil develop chain formations along the magnetic flux lines resulting in the resistance-toflow build up. The change is reversible and fast. It is also of sufficient strength to merit the application of these fluids in real world devices, e.g. controllable vehicle dampers or powertrain mounts [2]. In general, MR dampers are free of mechanical valves with moving parts. Several advantages of MR dampers over conventional semi-active systems include continuouslyvariable damping characteristics, high damping force gain (ratio of the force in the off-state to the maximum force in the energized condition), low power draw, very good response times below 12 ms [3]. The technology has drawbacks, too. Fluid cost, sedimentation, durability are the challenges that the technology needs to cope with [4]. Still, designing an MR damper is an engineering challenge. It is mainly due to the nonlinearities involved between the output force and the input current. Several conflicting criteria often need to be met when developing a specific configuration of an MR damper system. For example, they are: low force in the non-energized state, high force in the energized condition, optimum response time, mass, packaging and the like [1,3]. Gołdasz and Sapiński [3] classified flow-mode MR valves in terms of the number of flow paths, flow path geometry, coil-core arrangement, asymmetry, fail-safe characteristics, etc. Analysis of commercial MR damper configurations shows that the majority of flow-mode devices feature one primary flow path, one or two coil assemblies wound onto a ferr[...]

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