Influence of bonding on the efficiency of piezoceramic patches as actuators in smart structures

摘要

In smart and adaptive structures very often piezoceramic elements are used as sensors or actuators. If these elements are used as actuators, an optimized bonding is necessary for a good efficiency of the overall system. In experiments it was observed, that the quality of the bonding depends on several factors. Therefore, a systematic investigation of the problem is given in the present paper both theoretically and experimentally. The main focus of the paper is to elaborate a simple measurement both of the bonding thickness and of the overall coupling efficiency between the piezoceramic element and the elastic structure. In the paper it is shown that by measuring the electric impedance at different frequency bands it can easily be seen if a bonding is good or bad. The experimental results are compared with theoretical models. One of the main results is that the thickness of the bonding layer should be small, because the loss of the electric field in the ceramic due to the additional capacity between actuator and structure is most important if a nonconductive adhesive is used.