26 July 2004 Detection of fastener failure in a thermal protection system
Author Affiliations +
This paper presents experimental and analytical studies focused on the development of a structural health monitoring system to assess the condition of mechanical fasteners of a thermal protection system. A realistic thermal protection system component, consisting of a carbon-carbon panel bolted through 15 brackets to a backing structure, is utilized. Mechanical states considered include all bolts fastened to a nominal torque value, or one of the 15 bolts loosened. Four transducers on the backing structure provide actuation and sensing signals. Spectral functions are computed from all single and pair-wise signal combinations. Automated analysis of the spectral functions shows frequency intervals exist over which the function values are indicative of the mechanical state of the test article. These frequency intervals are used to provide features for the structural health monitoring classifier. Finite element analyses provide a physics-based understanding of these features. Statistical pattern recognition methods select a subset of the features. The overall localization accuracy of the structural health monitoring system on test data is 99.1% with 99.7% probability of detecting a damaged condition at a 0.2% probability of a false alarm.
© (2004) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Mark M. Derriso, Steven E. Olson, William R. Braisted, Martin P. DeSimio, John Rosenstengel, Kevin Brown, "Detection of fastener failure in a thermal protection system", Proc. SPIE 5390, Smart Structures and Materials 2004: Smart Structures and Integrated Systems, (26 July 2004); doi: 10.1117/12.562967; https://doi.org/10.1117/12.562967

Back to Top