Torsional Tuned Mass Damper System Parameter Identification with Experimental Method

Torsional Tuned Mass Dampers (TTMD) are used for attenuation of harmful effect of torque pulsation in internal combustion engines which originates due to reciprocating unbalance and gas forces. Torsional dampers use silicone oil inside a cylindrical cavity which houses an inertial ring. It is possible to use the theoretical models to estimate stiffness and damping properties of the TTMD, when the silicone oil is used in the damper. However when TTMD uses rheological fluid instead of plain silicone oil or any other additives are used in the silicone oil, it is difficult to estimate stiffness and damping with the theoretical methods. The present work demonstrates an experimental method to determine the vibration characteristics of TTMD. A custom designed fixture is used along with an accelerometer, time and frequency domain data analysis and arrangement to provide forced vibrations. Initially TTMD is excited with free vibrations and frequency response of the angular acceleration is measured, which is used to determine stiffness of the TTMD. Further, a harmonic torque as applied and the steady state amplitude of angular acceleration is measured, which is used to calculate damping coefficient of TTMD. The presented method exhibits 5-10% deviation in the estimated vibration parameters in comparison to the theoretically calculated values.