Parameter Identification of a Nonlinear Beam Energy Harvester

Author(s):  
Dennis J. Tweten ◽  
Brian P. Mann

This paper describes the application of the harmonic balance parameter identification method to beam energy harvesters. The method is applied to weakly nonlinear and nonlinear, bistable fixed-free piezoelectric beams with tip masses. It is shown that only one measurement is required to identify parameters even though the systems are continuous. In addition, an experimental method of determining the number of restoring force coefficients required to accurately model the systems is presented. The harmonic balance parameter identification method is extended to account for multiple concurrent frequencies in order to identify parameters of weakly nonlinear systems. Finally, parameters are identified for two experimental energy harvesters. Good agreement is shown between the experimental data and the identified parameters using simulations and closed form solutions.

AIP Advances ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 055302
Author(s):  
Yong Zhu ◽  
Guangpeng Li ◽  
Shengnan Tang ◽  
Wanlu Jiang ◽  
Zhijian Zheng

2017 ◽  
Vol 140 (2) ◽  
Author(s):  
Christopher G. Cooley ◽  
Tan Chai

This study investigates the vibration of and power harvested by typical electromagnetic and piezoelectric vibration energy harvesters when applied to vibrating host systems that rotate at constant speed. The governing equations for these electromechanically coupled devices are derived using Newtonian mechanics and Kirchhoff's voltage law. The natural frequency for these devices is speed-dependent due to the centripetal acceleration from their constant rotation. Resonance diagrams are used to identify excitation frequencies and speeds where these energy harvesters have large amplitude vibration and power harvested. Closed-form solutions are derived for the steady-state response and power harvested. These devices have multifrequency dynamic response due to the combined vibration and rotation of the host system. Multiple resonances are possible. The average power harvested over one oscillation cycle is calculated for a wide range of operating conditions. Electromagnetic devices have a local maximum in average harvested power that occurs near a specific excitation frequency and rotation speed. Piezoelectric devices, depending on their mechanical damping, can have two local maxima of average power harvested. Although these maxima are sensitive to small changes in the excitation frequency, they are much less sensitive to small changes in rotation speed.


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