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Magnetorheological Elastomers (MREs) are a class of smart materials that show variable deflection, stiffness, and damping properties when placed inside a magnetic field and hence, they have interesting and new engineering applications. The first part of the presentation demonstrates the design and performance of fail-safe MRE base isolators for structural applications. By implementing MREs in vibration isolators, we can construct newer, safer structures and the upgrade older structures so that they are able to better withstand seismic events. After performing quasi-static and dynamic shear experiments to determine the magnetic field dependent behavior of the MRE vibration isolators, a theoretical model is developed to predict their field-dependent behavior. The model is implemented in a control strategy to mitigate seismic vibrations in an isolated scaled building.
The second part of the presentation shows a flexible magnetic micropump inspired by the mechanism of lymph propulsion in lymphatic vessels. The system can transport biological fluids with a peristaltic movement which is essential in preventing damage to living organisms. Also for the first time, the performance of a flexible tubular magnetically actuated micropump is modeled and investigated using a coupled time-dependent magnetic and fluid-structure interaction analysis. Using the developed model, the effect of each geometrical parameters, material properties, and magnetic characteristics on the performance of the system is investigated.
The third part of the presentation describes the ongoing research for developing an adaptive bridge bearing that can sense structural loads and tune its properties to mitigate structural vibrations. The bearing utilizes MRE layers which allow for an increased stiffness induced by a magnetic field. The system also features a MRE-based sensing system for sensing the structural wind and traffic loads. The sensing system is capable of transmitting data wirelessly to a central logging computer for monitoring bridge performance and sending alerts in the case of a major event.
Dr. Majid Bejrooz, University of Nevada - Reno
Presented October 21, 2016
[No video recording at the request of the presenter]
About the Presenter
About the Presenter
Dr. Majid Behrooz is a postdoctoral scholar at the University of Nevada, Reno with expertise in magnetic smart materials and their application in vibration isolation and flexible micropump systems. He has conducted his doctoral research in the Composite and Intelligent Materials Laboratory where he served as a laboratory manager as well as a research assistant for five years. He has also served as an ASME officer for the ASME Northern Nevada Section where he helped fostering relationships among mechanical engineers and local industries. Currently, he is leading a group of undergraduate and graduate research assistants in developing an integrated smart base isolation and load sensing system for improving the durability and health monitoring of bridges. His researches have received support from the National Science Foundation and the Federal Highway Administration. He is the author of numerous publications in this area including six journal articles and fifteen conference proceedings which are cited over 100 times mainly by researchers around the world. He is an active reviewer for highly reputed journals of the field including Smart Materials and Structures, Intelligent Material Systems and Structures, Rheologica Acta, and the ASME Journal of Vibration and Acoustics.
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