Ferroelectric materials have been an area of keen interest for researchers due to their useful electro-mechanical coupling properties for a range of modern applications, such as sensing, precision actuation, or energy harvesting. The distribution of the piezoelectric coefficients, which corresponds to the piezoelectric properties, in traditional crystalline ferroelectric materials are determined by their inherent crystalline structure. This restriction limits the tunability of their piezoelectric properties. In the present work, ferroelectric lattice materials capable of a wide range of rationally designed piezoelectric coefficients are achieved through lattice micro-architecture design. The piezoelectric coefficients of several lattice designs are analyzed and predicted using an analytical volume-averaging approach. Finite element models were used to verify the analytical predictions and strong agreement between the two sets of results were found. Select lattice designs were additively manufactured using projection microstereolithography from a PZT-polymer composite and their piezoelectric coefficients experimentally verified and also found to be in agreement with the analytical and numerical predictions. The results show that the use of lattice micro-architecture successfully decouples the dependency of the piezoelectric properties on the material's crystalline structure, giving the user a means to tune the piezoelectric properties of the lattice materials. Real-world application of a ferroelectric lattice structure is demonstrated through application as a multi-directional stress sensor. / Master of Science / Ferroelectric materials have been an area of keen interest for researchers due to their useful electro-mechanical coupling properties for a range of modern applications, such as sensing, precision actuation, or energy harvesting. However, the piezoelectric properties of traditional materials are not easily augmented due to their dependency on material crystalline structure. In the present work, material architecture is investigated as a means for designing new piezoelectric materials with tunable sets of piezoelectric properties. Analytical predictions of the properties are first obtained and then verified using finite element models and experimental data from additively manufactured samples. The results indicate that the piezoelectric properties of a material can in fact be tuned by varying material architecture. Following this, real-world application of a ferroelectric lattice structure is demonstrated through application as a multi-directional stress sensor.

In an increasingly data-driven society, sensors and actuators are the bridge between the physical world and the world of "data." Electroacoustic transducers convert acoustic energy into electrical energy (or vice versa), so it can be interpreted as data. Piezoelectric materials are often used for transducer manufacturing, and recent advancements in additive manufacturing have enabled this material to take on complex geometric forms with micro-scale features. This work advances the additive manufacturing of piezoelectric materials by developing a model for predictive success of complex 3D printed geometries in Mask Image Projection-Stereolithography (MIP-SL) by accounting for mechanical wear on Polydimethylsiloxane (PDMS). This work proposes a framework for the rapid manufacture of 3D printed transducers, adaptable to a multitude of transducer element forms. Using the print model and transducer framework, latticed hydrophone elements are designed and tested, showing evidence of selectively tunable sensitivity, resonance, and directivity pattern. These technology advancements are extended to enable a workflow for users to input polar coordinates and receive an acoustic element of a continuously tuned directivity pattern. Investigation into customer problem spaces via tech-push methods are adapted from the NSF's Lean Launchpad to reveal insight to the problems faced in hydrophone applications and other neighboring problem spaces. / Master of Science / In an increasingly data-driven world, sensors are the bridge between the physical world and the world of "data." The better the sensor; the better the data. Electroacoustic transducers are sensors that convert acoustic sound energy into electrical energy or vice versa. These are observed in the world around us as microphones, speakers, ultrasound devices, and more. In the early 1900's, piezoelectric materials became one of the dominant methods for transducer creation, and recent advancements in additive manufacturing have enabled this material to take on highly complex geometric forms with micro-scale feature sizes. Further advancements to additive manufacturing of piezoelectric materials are contributed through development of a model for predicting the success of complex 3D printed geometries in an Mask Image Projection-Stereolithography (MIP-SL) by accounting for mechanical wear on the Polydimethylsiloxane (PDMS) print window. This work proposes a framework for the rapid manufacture of 3D printed transducers, adaptable to a multitude of element forms. Using the developed print model and transducer framework, latticed hydrophone elements are designed and tested, showing evidence of selectively tunable sensitivity, resonance and beampattern. The advancements in technology are extended to enable a workflow for users to input polar coordinates and receive an acoustic element of continuously tuned beampattern. Investigation into customer problem spaces via tech-push methods are adapted from NSF's Lean Launchpad and reveals great insight to the problems faced in hydrophone applications and other neighboring industry spaces.