Structural components with integrated piezoceramic sensors and actuators manufactured by high pressure die casting were studied using the thermal wave method. Thermal waves were created by irradiating the surface with an intensity modulated laser beam, and the pyroelectric current was monitored in dependence on modulation frequency. Laser modulation frequencies corresponding to specified penetration depths of the thermal wave were determined by a thermal finite element analysis. The current spectrum was fitted to complex relaxation models. The embedded piezoelectric transducer was described as a homogeneously poled, harmonically heated piezoelectric plate exhibiting heat losses to the environment. Nyquist plots were used for physical interpretation as an equivalent circuit.
