12. Tubular Shell Energy Harvester

This chapter involved energy harvesting of a simply supported tubular (circular) cylindrical shell laminated with piezoelectric patches. The distributed modal energy generations using different energy harvester patch sizes (i.e., (1 mm,3.6°) in Case 1, (10 mm,30°) in Case 2, and (20 mm,60°) in Case 3) at various mode numbers were evaluated in case studies. Analytical and simulation results suggest that the maximum magnitude of the spatially distributed modal energies changes at various modes in two cases, due to the patch size enlarged or the number of energy harvester patches in the circumferential direction decreased. It should be noted that the signal averaging effects on energy harvester patches become more significant when the patch size continuously increasing. Additionally, the bending energy components are much smaller than the circumferential membrane energy component, and they increase when mode number increases. Furthermore, the maximum magnitude of the (m, n)th modal energy, in general, increases when energy harvester’s thickness h_p or shell’s thickness h increases, but decreases when the shell radius R increases. A tubular shell energy harvesting system was designed and tested in the StrucTronics and Control Laboratory at Zhejiang University. Experimental results suggest that there is an optimal external loading resistance leading to the maximal power output. Both analytical predictions and experimental data were compared favorably. These data evaluated in this study can be used as guidelines to design the optimum piezoelectric energy harvester in practical engineering applications.