TY - GEN

T1 - Response of uni-modal duffing-type harvesters to random excitations

AU - Daqaq, Mohammed F.

PY - 2011

Y1 - 2011

N2 - The common linear energy harvesters have an inherent shortcoming in their operation concept because they operate efficiently only when the excitation frequency is very close to the fundamental frequency of the harvester. To extend the harvester's bandwidth, some recent solutions call for utilizing energy harvesters with stiffness-type nonlinearities. From a steady-state perspective, this hardening nonlinearity can extend the coupling between the excitation and the harvester to a wider range of frequencies. In this effort, we investigate the response of such harvesters to Gaussian White and Colored excitations. For Gaussian White excitations, we solve the Fokker-Plank-Kolmogorov equation for the exact joint probability density function of the response. We show that the expected value of the output power is not even a function of the non-linearity. As such, under White Gaussian excitations, nonlinearities in the stiffness do not provide any enhancement over the typical linear harvesters. Furthermore, we demonstrate that nonlinearities in the damping or inertia should be sought to enhance the output power. We also use the Van Kampen expansion to analyze the response to Colored excitations of different bandwidths and center frequencies. Again, we show that, regardless of the bandwidth or the center frequency, the expected value of the power is always less than that associated with a linear harvester.

AB - The common linear energy harvesters have an inherent shortcoming in their operation concept because they operate efficiently only when the excitation frequency is very close to the fundamental frequency of the harvester. To extend the harvester's bandwidth, some recent solutions call for utilizing energy harvesters with stiffness-type nonlinearities. From a steady-state perspective, this hardening nonlinearity can extend the coupling between the excitation and the harvester to a wider range of frequencies. In this effort, we investigate the response of such harvesters to Gaussian White and Colored excitations. For Gaussian White excitations, we solve the Fokker-Plank-Kolmogorov equation for the exact joint probability density function of the response. We show that the expected value of the output power is not even a function of the non-linearity. As such, under White Gaussian excitations, nonlinearities in the stiffness do not provide any enhancement over the typical linear harvesters. Furthermore, we demonstrate that nonlinearities in the damping or inertia should be sought to enhance the output power. We also use the Van Kampen expansion to analyze the response to Colored excitations of different bandwidths and center frequencies. Again, we show that, regardless of the bandwidth or the center frequency, the expected value of the power is always less than that associated with a linear harvester.

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U2 - 10.1007/978-1-4419-9716-6_20

DO - 10.1007/978-1-4419-9716-6_20

M3 - Conference contribution

AN - SCOPUS:80051481018

SN - 9781441997159

T3 - Conference Proceedings of the Society for Experimental Mechanics Series

SP - 219

EP - 226

BT - Structural Dynamics and Renewable Energy - Proceedings of the 28th IMAC, A Conference on Structural Dynamics, 2010

PB - Springer New York LLC

ER -