Benchmarking dynamic properties of structures using non-contact sensing

Non-contact sensing can be a rapid and convenient alternative for determining structure response compared to conventional instrumentation. Computer vision has been broadly implemented to enable accurate non-contact dynamic response measurements for structures. This study has analyzed the effect of non-contact sensors, including type, frame rate, and data collection platform, on the performance of a novel motion detection technique. Video recordings of a cantilever column were collected using a high-speed camera mounted on a tripod and an unmanned aerial system (UAS) equipped with visual and thermal sensors. The test specimen was subjected to an initial deformation and released. Specimen acceleration data were collected using an accelerometer installed on the cantilever end. The displacement from each non-contact sensor and the acceleration from the contact sensor were analyzed to measure the specimen’s natural frequency and damping ratio. The specimen’s first fundamental frequency and damping ratio results were validated by analyzing acceleration data from the top of the specimen and a finite element model.