Integrated structural health monitoring
Acellent Technologies Inc. (Sunnyvale, Calif.) has introduced SmartLayer, a flexible circuit material with embedded piezoelectric sensors that can be bonded to or within composite structures for use in structural health monitoring (SHM). It allows signals to be sent, received and analyzed at any time to determine if structural characteristics within the composite material have changed due to damage or some other force. By combining results of numerous send/receive signal propagation pathways, the damage location and size reportedly can be estimated accurately based on which specific detected signal paths have changed, and how they have changed, compared to the new, presumably undamaged structure. In most cases, temperature sensing is included on a SmartLayer flexible circuit, allowing baseline data to be calibrated across an environmental range, improving its damage detection sensitivity during subsequent SHM examinations. The company also offers a line of amplifiers, signal filters, data-collection hardware, and analytical software, including code specifically written for composite applications. Beyond damage detection, this SHM system reportedly delivers additional benefits that include a reduction of mechanical design margins and associated structural mass because the system provides more concrete data about the general health of the structure. The manufacturer says this usually translates to considerably more structural weight-saving opportunity than that afforded by sensor networks. Other reported benefits include inspections that can be performed without disassembly and the fact that composite structures need not be discarded simply because of age or use history.