Piezoelectric truss metamaterials: data-driven design and additive manufacturing

Area of Science:

• Materials Science
• Metamaterials
• Piezoelectric Engineering

Background:

• Natural piezoelectric materials have inherent directionality limited by crystal symmetry.
• This constraint restricts the achievable property space in conventional piezoelectric materials.
• Mesoscale geometry and architecture offer a route to overcome these limitations.

Purpose of the Study:

• To develop a framework for designing and 3D-printing piezoelectric metamaterials.
• To achieve customizable anisotropic piezoelectric responses.
• To explore unconventional piezoelectric behaviors like auxeticity and directional responses.

Main Methods:

• Utilized generative machine learning for designing truss metamaterials.
• Developed an in-gel 3D printing method for fabrication.
• Employed a composite slurry of photo-curable resin and lead-free piezoelectric particles.

Main Results:

• Achieved customizable anisotropic piezoelectric responses, including auxetic, unidirectional, and omnidirectional behaviors.
• Demonstrated over 48% improvement in specific hydrostatic piezoelectric coefficient compared to bulk lead zirconate titanate (PZT).
• Observed higher transverse than longitudinal piezoelectric coefficients, a rare phenomenon.

Conclusions:

• The proposed framework enables the design of piezoelectric metamaterials with tailored responses.
• The 3D printing method allows for the fabrication of complex piezoelectric structures.
• This work opens avenues for developing advanced electro-active materials with tunable properties.