Robust design of MR elastomer for optimal isolation against non-stationary ground motion

The robust design of magneto-rheological elastomer in the presence of seismic uncertainty is the theme of this work. This issue is addressed by optimizing the phenomenological parameters to ensure robustness. Once the fundamental characteristics are tuned, minor adjustment can be carried out using current flow to meet the instantaneous demand for control force. For this purpose, subset simulation is proposed in this study. The rationale behind the selection of subset simulation is its ability to estimate probability using very few samples. The proposed robust design methodology is demonstrated using simulated samples of El Centro ground motions. However, the method is general and can be adopted for any other uncertainty model, specific to a particular structure or location. The proposed robust design of magneto-rheological elastomer is verified using a three-storied frame that clearly shows the advantage of tuning the phenomenological parameters of the isolator. Finally, the performance of the optimal isolator is also demonstrated using different recorded earthquakes and the performance of an isolator is discussed in the light of different structural performance index.