Experimental determination of damping property of structure

Abstract

The needs for reliable and accurate damping properties are necessary in order to produce a good simulation and improve a major source of uncertainty at the design stage. Thus, an experimental investigation was conducted to find damping property of structure. In this study, three different plates were used to determine their damping properties. Experimental modal analysis using impact hammer and accelerometer was performed to acquire the frequency response function (FRF) of test samples. Damping properties were extracted from FRF using polyreference least-squares complex frequency-domain method (PolyMAX) and polyreference least-squares complex exponential time-domain method (LSCE). The results reveal that for lightly damped structure, the damping ratio from LSCE and PolyMAX are comparable. However, for heavily damped structure, the damping ratio from LSCE is slightly higher than damping ratio from PolyMAX. The results also show that PolyMAX is better than LSCE in term of stabilisation diagram. Finally some improvements on the experimental method have been proposed in order to achieve accurate damping property.