A Quick Method for Assessing Transducer Mass Effects on the Measured FRFs

Abstract

In modal testing, the measured Frequency Response Functions (FRFs) are often affected by the mass loading of the transducers (such as force transducer and accelerometer) installed on the test structure. This paper proposed a quick method for assessing transducer mass effects on the measured FRFs (including point and transfer FRFs). The assessment method offers some distinct advantages in that very few FRFs measurements are required, and more importantly it does not require calculations involving several measured FRFs, hence avoiding further contaminations of the measured data. In this method, both force transducer and accelerometer masses effects have be considered. And the overall as well as the individual mass effects of the two transducers (force transducer and accelerometer) have been assessed, respectively. A simple numerical example presented illustrates good theoretical performance of the method. To simulate an experimental situation, the same example is extended to incorporate noise, and it is shown that the accuracy of assessment results will be affected to some extent by the noise. A possible solution to this problem is to preprocess the measured FRFs using the curve-fitting procedure before the proposed method is applied.