Development of magnetorheological elastomer technologies for protecting structures from seismic events

Protecting civil engineering structures from uncontrollable events such as earthquakes while maintaining their structural integrity and serviceability is very important. Various methods have been developed to either reinforce the protected structures or isolate the seismic motions. Passive aseismic methods and active aseismic methods used to be attractive methods, however, their respective inherent drawbacks limit their wide acceptance. Semi-active methods, which synergize the advantages of both passive and active methods, have been popularly and widely accepted since their emergence. One of the many ways to implement semi-active devices based on magnetorheological elastomers (MREs). This thesis first provides a literature review on the recent progress of MREs and their applications. The investigations into the mechanical property, the ingredients, the preparation process, the modelling of MREs as well as the internal and external factors that influence their properties have been the research hotspot during the past decades. Then research interests arose in the implementation and development of smart devices using MREs, including MRE isolators, MRE tuned mass damper, and MRE absorbers. For the purpose of protecting buildings from seismic motions, base isolation and tuned mass damper are two major technologies. MRE base isolation aims to decouple the protected structures from the ground motions once earthquakes happen by being installed between them, while MRE tuned mass damper intends to track and identify the vibration frequency so that the vibration energy can be transferred to the tuned mass damper leaving the structures undamaged. In order to lay the groundwork for the new designs of MRE base isolator and MRE tuned mass damper in the following chapters, comprehensive reviews on their development evolutions are also included.