Additively Manufactured Sensors for SHM of Composite Structures

Polyvinylidene fluoride (PVDF) is a widely used material for properties such as piezoelectric sensing, good chemical resistance, high thermal stability, low acoustic impedances and flexibility. Lead zirconate titanate (PZT) is a piezoceramic with its perovskite phase having good sensitivity and high operating temperatures which has number of applications as ultrasonic transducers and piezoelectric resonators. There is much need of synergizing the sensing and actuation capabilities of both the materials and thus expanding the potential applications on lightweight composite structures with complex geometries. Fused layer deposition is one of the additive manufacturing techniques which helps in achieving the above objective. In this paper, we study the 3D printing of solvent assisted PVDF-PZT nanocomposite sensor and their integration into smart composite structures. 3D printable piezoelectric material is synthesized by the optimum dispersion of PZT nanoparticles to PVDF that is dissolved in solvent. Piezoelectric sensors are 3D printed on the fabric composite surface to study the strain effects during deformation. Electrode printing is carried out using screen printing technique. Impact tests are carried out to study the transient response of the sensors. Dynamic response of sensor is also characterized on an electrodynamic shaker. The effect of strain on the electrical impedance characteristics is studied. Overall performance indicates that these 3D printed sensors can have potential applications in SHM of composite structures for aerospace applications, IoT and robotic automation