3D Printed Honeycomb Infill Structure in Bimorph Piezoelectric Vibration Energy Harvesting

With technological advancement, renewable energy resources have become an essential element for sustainable applications. Vibration energy harvesting transforms wasted vibration from the environment into electricity. Structural stiffness correlates to the vibrational amplitude and various infill structures have been studied to enhance the displacement of the cantilever. Honeycomb has shown better results as compared to other different shapes. The generated power density is a crucial factor in harvesting energy from ambient which ranges from 0-150 Hz for road vibration to a tower’s vibration. This research incorporates a compact honeycomb structure with a piezoelectric energy harvester to improve generated power output. The different wall thicknesses of honeycomb infill structure and conventional solid substrate were studied for electrical energy generation through a bimorph piezoelectrical cantilever beam vibration energy harvester. The honeycombs were 3D printed with Polycarbonate material for 0.2 mm and 0.4mm wall thicknesses. A cellular honeycomb structure greatly lowers the harvester's overall mass while maintaining flexural strength. Experimentation with a shaker and LabView shows that a honeycomb with thicker walls will provide better displacement and eventually energy generation. Despite solid substrates producing higher power output, honeycomb structure gives higher power density of 4.81 mW and 4.4 mW for 0.2 mm and 0.4 mm wall thicknesses as compared to 2.71 mW for solid substrate. Honeycomb structure possesses higher rigidity and structural flexibility to accommodate different shapes and sizes. With proper manipulation of the geometrical aspects of the honeycomb, the relative power density can be increased to enhance energy generation.