Hybrid sets of merged data for modal model applications

Abstract

Often times, data is collected from a variety of different measurement systems that address different frequency ranges where the particular measurement system is well suited. These data sets may come from traditional accelerometer measurements and laser measurements and need to be merged into one complete data set. This can pose some difficulties when the measurement points are not collocated and reside at different points on the structure. With the advent of the use of optical measuring systems such as digital photogrammetry and digital image correlation techniques, the sets of points become even more complicated and a strategy is needed to merge all the data into one complete, scaled data set. This paper presents an approach to take multiple sets of data collected over different frequency ranges and different sets of points to form one complete set of modal vectors to be used for the description of the modal data set. The use of model expansion approaches and a finite element model are used for this work. A set of data is collected to illustrate the approach. Discussion of the results obtained is presented.