Noise control of the common base frame of a genset

Diesel engine driven generators are rigidly mounted on a welded steel plate structure called the common base frame (CBF). Formerly the engine was considered as the only significant sound source but recent studies have shown that the sound power radiation from the CBF is almost comparable to the engine. Constrained layer damping was selected as a noise control method for the CBF. The dimensions and number of the dampers were designed using FEM. The chosen damper configuration was installed on the CBF and tested during a standard factory acceptance test. Measured insertion loss was significant but lower than expected and the effective frequency range differed from the simulation. The major reason for the discrepancies was the deviation of the estimated operational temperature from the actual. Validation of the material model also improved the correlation between measurements and simulations.