The concept of “Shear Neutral Area” was proposed for constrained damping plate compared to “Shear
Neutral Axis” for beam. Based on Deformed Energy Principle, structural loss factor was analyzed by optimizing the
thickness of damping layer, and then tests were executed. Results show when damping layer is thin, the thickness of
damping layer and constrained layer are consistent to actual measurement, indicating the rationality of the analysis
method