Semiactive tuned mass damper for floor vibration control

A semiactive magnetorheological device is used in a pendulum tuned mass damper (PTMD) system to control the excessive vibrations of building floors. This device is called semiactive pendulum tuned mass damper (SAPTMD). Analytical and experimental studies are conducted to compare the performance of the SAPTMD with its equivalent passive counterpart. An equivalent single degree of freedom model for the SAPTMD is developed to derive the equations of motion of the coupled SAPTMD-floor system. A numerical integration technique is used to compute the floor dynamic response, and the optimal design parameters of the SAPTMD are found using an optimization algorithm. Effects of off-tuning due to the variations of the floor mass on the performance of the PTMD and SAPTMD are studied both analytically and experimentally. From this study it can be concluded that for the control laws considered here an optimum SAPTMD performs similarly to its equivalent PTMD, however, it is superior to the PT]MD when the floor is subjected to off-tuning due to floor mass variations from sources other than human presence. It is also found that for the case of off-tuning due to floor mass variations from the human occupants when the human-structure dynamic interactions are not considered in the analytical modeling, large inconsistencies between the analytical and experimental results can be expected.