Researches on the Accurate Measuring Method of Structure's Internal Loss Factor by Power Input Method

摘要

The theory of measuring internal loss factor of a multi-modal structure was studied in this paper. A new formula was brought out, which takes into account that the modal with the smallest damping contributes greatly to the whole response of all modals. The error of measuring internal loss factor using power input method was also discussed. Numerical simulations were done and results were given. It was found that the number of test points influences greatly on the measure error. Guideline was given on how to choose the most smallest number of test points while maintaining measure accuracy.