Open Access Open Access  Restricted Access Subscription Access

Co-Bonding of Piezoelectric Sensors on CFRP Structures

M. BACH, B. ECKSTEIN, N. JACQUEL, R. BERTRAND, C. STOLZ

Abstract


In order to replace conventional Non Destructive Testing (NDT), SHM needs to be at least as reliable and cost effective as the competing NDTTechnology. With respect to high recurring costs for sensor installation assuming state-of-the-art application procedures, wide area utilization with SHM sensors in aircraft seems to be not feasible. This results from the currently used secondary bonding process, at which the sensors are bonded to the cured structure by a multistage process. In order to reduce complexity, costs and required time of the bonding process, cobonding of the sensors is envisaged. Co-bonding is leading to several benefits regarding the process, as the sensors are applied outside the critical manufacturing path, but is leading at the same time to challenges regarding the sensor requirements. These requirements are outlined in the present work. In this context, different possibilities of sensor protection systems are presented. Additional the main basic requirement - “do the sensors survive the autoclave-process?†- of sensor co-bonding is successfully tested using commercial available PZT-sensors. For this reason, several sensors were placed in different configurations on the wet material of a generic CFRP specimen and put into the standard autoclave process. To determine the degree of degradation, several self diagnosis tests are conducted. As a second step, sensors will be applied on a more realistic specimen. As result, the authors present the capability for co-bonding of PZT-sensors in principle, but challenging with respect to different aspects.

Full Text:

PDF