Examination of the vibroacoustic behavior of a grid-stiffened panel with applied passive constrained layer damping

This paper provides a contribution to the understanding of both the vibroacoustical behavior and the influence of passive constrained layer damping (PCLD) applications on the sound radiation of a grid-stiffened panel. A test specimen is manufactured and an experimental set-up with a synthetic turbulent boundary layer excitation is developed. In addition, a numerical model is created and updated with the results of an experimental modal analysis. Further, the acoustic effect of PCLD applied to the ribs and to the skin fields of the grid panel is assessed by measurement of the radiated sound power. It is shown that the ribs are suitable for an efficient application of PCLD. Generally, additional damping of the grid panel is achieved with PCLD for frequencies above 300 Hz. By partially covering the ribs with PCLD, a reduction of the radiated sound power of up to 2 dB in third-octave bands is achieved. In case of a total coverage of the grid panel, a reduction of up to 4 dB in third-octave bands is attained.