The objective of this Interdisciplinary Research (IDR) grant is to explore a novel hierarchical approach that incorporates design of non-conventional lattice topologies with geometric nonlinearities and buckling-induced softening to lower the operational phononic frequency range for effective energy harvesting. The need for efficient and reliable electrical power sources for micro-electro-mechanical systems, wireless sensors and electronic portable devices, calls for innovative electromechanical structures and material systems capable of harvesting electrical energy from low frequency environmental mechanical vibrations. Unfortunately, a material's density and modulus become a pair of competing design constraints that prevent the realization of energy harvesting device with low operational frequencies. Through synergized approach among multiscale modeling, design optimization, micro-fabrication and experimental validation, this grant supports the bold effort in achieving superior electromechanical energy conversion of electroactive polymer based phononic crystals featuring simultaneous energy harvesting and vibration isolation capabilities.
If successful, this research will reveal the energy harvesting mechanisms of microstructured phononic metamaterials through a deep understanding of the interplay between phononic bandgaps and the mechanical-electrical coupling in the electroactive polymer materials. The extension of level-set based topology optimization to multi-functional and multi-material design will help establishing a rigorous and computationally viable design framework accounting for the highly nonlinear and coupled mechanical-electrical phenomena of electroactive polymers, while enabling two-way communication between manufacturing and design. The integrated micro-fabrication procedure with rapid prototyping capability will offer "hardware-in-the-loop" proof of concepts using fully functional prototypes. The fruition of this research is expected to be the forging of boundaries between the multidisciplinary researchers from science-based mechanics of materials, design optimization, photonic and phononic metamaterials and micro-fabrication for advancing the field of "phononic metamaterials-based energy harvesting," while training the next generation of scientific and engineering leadership in an interdisciplinary learning environment.