Damage Assessment in Adhesively Bonded Structures by Using SmartSHM

Adhesively bonded joints are attracting increasing interest in a wide range of industries, especially in transportation sectors (marine, automotive, aerospace), due to manifold advantages compared to conventional joining techniques such as riveting and welding. Therefore, both the design of adhesive joints as well as the assessment of possible failures in bonded structures during service life is of great concern. This paper presents a novel approach for an efficient SHM technique. The approach is presented and discussed on the basis of two different adhesively bonded applications, namely the single lap joint configuration and a one sided repair patch, which can be considered as a special case of single lap joints. The SmartSHM technique is based on the use of structural damage indicators. For single lap joints, the approach is related to the shift of the back face strain curve and its zero crossing due to crack initiation. Considering the repair patch, bending effects in longitudinal and transverse direction are investigated in 2D and 3D numerical analyses. Especially transverse bending effects show high potential for a SHM system based on two circumferential optical fiber sensors.