Numerical Study on Design and Installation of Energy-Harvesting Modules Embedded within a Flexible Pavement Structure

Previous analytical and experimental works have shown that the power output of a piezoelectric-based energy-harvesting module is nonlinearly proportional to compressive stresses. This study aims to identify an optimal set of operating conditions (materials and dimensions, traffic speed, type of vehicle, and environmental conditions) that would maximize the stress experienced by the piezoelectric elements. This research goal was achieved through a finite element parametric study that evaluated the influence of several design and installation variables on the performance of a hypothetical energy-harvesting system. The prototype of the energy-harvesting module was modeled as a sandwich structure, consisting of packing plates enclosing four piezoelectric elements and a soft material filling the voids. This module was embedded within a flexible pavement structure with viscous material properties. The effects of packing cover stiffness, asphalt layer thickness, and elastic modulus of the asphalt layer were evaluated under static simulations. Dynamic analyses were conducted to determine the effects of vehicle speed, temperature variation, and filler material on the performance of the energy-harvesting system. In addition, the probability that the entire tire width of a traveling vehicle will be directly on top of the module was calculated in order to identify potential widths for the energy-harvesting module. The numerical results suggest that the energy-harvesting module should be placed at locations of slow traffic movements and hot climatic regions within close proximity to the pavement surface.