Enhancing Standard GVT Measurements with Digital Image Correlation

Abstract

In recent years, high-speed cameras permit to record high-resolution images at several thousand frames-per-second. In addition to this, Digital Image Correlation (DIC) measures full-field displacements and strains in 3D from stereo camera images and perform Operational Deflection Shape and Modal Analysis on the data. Several papers have demonstrated the validity of the approach on laboratory cases, comparing and validating the results with those obtained using more standard measurement techniques (accelerometers, strain gauges, lasers). Very limited cases have been however investigated on the possibility to combine high-speed DIC and standard accelerometer-based measurement to fully exploit the advantages of both techniques. In this paper, the possibility to combine global acceleration measurements on an F16 during a classical Ground Vibration Test with local full-field camera measurement is investigated. The advantages of the combined approach are clear, as the standard measurement will provide the global mode shapes of the aircraft, which can be used for certification and modal validation, while the local high-speed camera measurement system can provide displacement and strain field data with an unmatchable spatial resolution. In particular, the paper will focus on the possibility of using the local displacement measurements to better characterize the non-linear behavior of the connection between the wing and the payload.