Manufacturing of CFRP Panels with Integrated Sensor Network and Contacting of the Network

Structural health monitoring systems are considered nowadays as ones of the most promising technologies for improving the economics of commercial aircrafts. An ideal SHM system could be capable of indicating the type of damage, its size, location, severity, and estimate the remaining lifetime of the structure. Until now, several technological approaches have been implemented under the scope of SHM systems. One of the most efficient methodologies is the application of guided ultrasonic waves (Lamb waves). This paper will focus on the Lamb wave technique and describe the road map followed along with the instrumentation developed to process the derived signals. For the implementation of such system, two types of piezoelectric sensors have been tackled. The “Smart Layer” provided by Acellent and the DuraAct™ sensors fabricated by Invent GmbH. The “Smart Layer” is based on polyimide layers. At specific spots, PZT are embedded in the layer and they are connected to the main connector by means of a copper circuit. On the other hand, DuraAct™ sensors are piezocomposites which consist of piezoceramic materials embedded in a ductile polymer. In order to study the performance of these systems, physical demonstrators have been manufactured. Representative composite fuselage structures incorporating curved skin panels with omega stringers made from CFRP materials have been designed and produced. Arrays of both types of PZT sensors have been integrated onto these structures inserting by this mean sensors at certain positions which could identify a potential damage. After the finalization of the production process, the panels were impacted and a damage detection analysis was performed based on the acquired data of the Lamb wave propagation through the manufactured panels. Under this analysis, the two different sensor networks were evaluated in terms of reliability, repeatability, and probability of detection by determining the allowable damage size (a_90/95), which will be detailed in associated papers of AS06.