Session: SYMP 7-4: Energy Harvesting - Invited Talk

Paper Number: 140211

140211 - Experimental Studies on Enhancing Piezoelectric Coupling Using Nonlocal Interactions 

It is essential to explore microscale energy harvesting techniques, such as piezoelectricity, to extract energy for diverse applications such as wireless sensors, microactuators, personnel tracking, and structural health monitoring. Although piezoelectric energy harvesting is well established, its efficacy is restricted to a limited bandwidth of frequencies for ambient vibrations. This places considerable limitations on the base structure (geometry and material distribution) and the frequency of ambient vibrations. Various techniques have been proposed to improve the efficiency of piezoelectric energy harvesters over a broad range of operating frequencies. Examples include modification of piezo-configuration (unimorph/bimorph), resonance tuning, and introducing nonlinearities. While most of these ideas are well established, they suffer from several disadvantages. Alternatively, metastructures are proposed as an alternative that achieves enhanced electro-mechanical energy conversion via appropriate structural design to localize the vibrations and trap the energy for extraction through a piezoelectric patch. Recently, it has been proposed to leverage the nonlocal interactions for tuning the multiphysics coupling in smart structures. For instance, an acoustic black hole (ABH) represents a nonlocal structure that achieves energy concentration at a point via a specific power-law variation for thickness profile. This nonlocal approach presents an exciting potential for amplifying the efficacy of piezoelectric energy conversion by enhancing the degree of multiphysics coupling.  

The study aims to investigate the electro-mechanical response of a nonlocal smart beam, specifically a nonlocal substrate with a piezoelectric patch in unimorph configuration, subject to vibrations over a wide range of frequencies. We propose to realize nonlocal interactions across the domain of the substrate beam via intricate geometric features and material distribution in the form of an ABH structure. Given the complexity of the design, we used an SLA-based 3D printer to fabricate the metastructure using photopolymer resin. The resulting 3D-printed metastructure is subject to vibrations by a mini-shaker. More specifically, the substrate beam is subject to base excitation using a function generator. The function generator is expected to simulate ambient vibrations, which are subsequently amplified by the power amplifier for driving the mini-shaker. This mini-shaker then induces controlled vibrations in the smart beam, and the resulting piezoelectric voltage generated by the energy harvester is measured and recorded. Fine-tuning of the nonlocal interactions across the ABH structure is expected to significantly enhance the electrical energy harvested by the PZT-5H over a wide range of frequencies. Subsequently, the experimental observations are validated with numerical studies conducted in commercial FEA software, COMSOL Multiphysics. Finally, we propose to establish the efficacy of nonlocal interactions in tuning the multiphysics coupling, and thereby, a possible improvement in the degree of coupling. This comprehensive exploration and optimization of the electro-mechanical interaction opens the way for innovative energy-harvesting applications in various fields. We note that this methodology can also be extended to other multiphysics domains, including electromagnetic, ferroelectric, and triboelectric energy harvesting methods. 

Presenting Author: Shubham Desai Indian Institute of Technology, Hyderabad

Presenting Author Biography: I am a research scholar at the Indian Institute of Technology, Hyderabad, collaborating with Dr. Sai Sidhardh. My current research focuses on exploring nonlocal piezoelectric phenomena using fractional calculus. Our approach, based on fractional calculus, shows considerable potential in enhancing the performance of actuators and sensors. Our recent publication in the International Journal of Numerical Methods for Engineering presents an Element‐free Galerkin method for a fractional‐order boundary value problems. Additionally, we have another paper currently undergoing review, which delves into constitutive modeling of nonlocal piezoelectricity following a fractional calculus approach.

Authors:

Shubham Desai
Sai Sidhardh