Directional dependence of the static response of layered piezoelectric transducers

Directionality of the static response of piezoelectric transducers is investigated in terms of strain and stress piezoelectric constants. Layered transducers that are composed of several orthotropic passive layers and one single active layer are considered. Both monolithic and composite piezoelectric layers are taken into account. Equivalent properties are derived via analytical mixing rules and validated towards a numerical homogenisation method. A design that guarantees maximum directional dependence in terms of strain piezoelectric constants is proposed. Transducer’s response in terms of directionality when it is mounted as a sensor patch on a mechanical structure is investigated.