Structural integration of PZT fibers in deep drawn sheet metal for material-integrated sensing and actuation

Today, adaptive sheet metal parts are manufactured by surface bonding of sensors and actuators on shaped structural parts. This paper presents a technology for direct structural integration of lead-zirconate-titanate (PZT) fibers in flat sheet metal and subsequent shaping. Microcavities are microformed into the surface of the metal sheet in which piezoceramic fibers are inserted and joined. After that, the composite is shaped by deep drawing into a complex 3D surface. The production technology is discussed in detail with regard to the limits of each process step. Functional shaped prototypes with ten interconnected parallel piezoceramic fibers were fabricated. The function as transducer and sensor for lamb waves is demonstrated and the degradation due to the shaping is compared for different parameters of the deep drawing process. The composite shapes are cups with a double curvature radius of 100 mm and 250 mm respectively. As a result, degradation of the piezoelectric function varies as a consequence of the process parameters. In the best case, a degradation of the transducer function of 33 % was shown in the experiments. The cause of the decreased performance after shaping is discussed and explained by debonding mechanisms. Results of numerical simulations show good agreement with the experimental findings of the optimum process parameters. (C) 2014 The Authors. Published by Elsevier Ltd.