Monitoring the integrity of machine assemblies by using surface response to excitation (SuRE) approach

Fully automated integrity inspections of assembled autonomous space vehicles components are essential for their reliable and cost effective operation. Many researchers have already used structural health monitoring (SHM) methods for detecting loose bolts, plate defects, and many other structural problems. This study had two objectives. First, the performance of the surface response to excitation (SuRE) approach was tested for the detection of the compressive forces of a clamp applied to a small plate. The test indicated that the suRE approach could be used for detection of loose bolts attached to an aluminum plate. Secondly, the same approach was tested when the clamp was attached to a plate which was welded to the plate carrying the actuator and the sensor. The study demonstrated that the swept sine waves transmit through the welded joints. The integrity of the components could be evaluated by using the sensor and actuator located at another plate, as long as the plates are welded properly. The Lamb wave approach was also tested in both test conditions. SuRE approach was easier to interpret compare to the envelopes of the Lamb wave approach for our relatively small plates.