1. Date of download: 9/17/2016 Copyright © ASME. All rights reserved. From: Frequency Tuning of a Nonlinear Electromagnetic Energy Harvester J. Vib. Acoust. 2013;136(1):011010-011010-7. doi:10.1115/1.4025445 Schematic of a tunable electromagnetic energy harvester Figure Legend:

2. Date of download: 9/17/2016 Copyright © ASME. All rights reserved. From: Frequency Tuning of a Nonlinear Electromagnetic Energy Harvester J. Vib. Acoust. 2013;136(1):011010-011010-7. doi:10.1115/1.4025445 Equivalent mechanical model of an electromagnetic harvester Figure Legend:

3. Date of download: 9/17/2016 Copyright © ASME. All rights reserved. From: Frequency Tuning of a Nonlinear Electromagnetic Energy Harvester J. Vib. Acoust. 2013;136(1):011010-011010-7. doi:10.1115/1.4025445 The schematic model of elastic strings and mass Figure Legend:

4. Date of download: 9/17/2016 Copyright © ASME. All rights reserved. From: Frequency Tuning of a Nonlinear Electromagnetic Energy Harvester J. Vib. Acoust. 2013;136(1):011010-011010-7. doi:10.1115/1.4025445 The nondimensional force-deflection characteristic given by Eq. (6) (solid line), and its approximation by Eq. (8) (dashed line), for the stretch ratio l˜ = l0/l = 0.9, where the error of points marked by triangle is greater than 5% Figure Legend:

5. Date of download: 9/17/2016 Copyright © ASME. All rights reserved. From: Frequency Tuning of a Nonlinear Electromagnetic Energy Harvester J. Vib. Acoust. 2013;136(1):011010-011010-7. doi:10.1115/1.4025445 The change in frequency of vibration as a function of the stretch ratio of the elastic string, where the initial conditions of the system are set to u(0) = u0 = 0.3 l0 and u·(0) = u·0 = 0. The curve marked with triangle is drawn according to Eq. (15), and that marked with circle is drawn by Ω1 = γ1. Figure Legend:

6. Date of download: 9/17/2016 Copyright © ASME. All rights reserved. From: Frequency Tuning of a Nonlinear Electromagnetic Energy Harvester J. Vib. Acoust. 2013;136(1):011010-011010-7. doi:10.1115/1.4025445 Frequency-response curves with constant ξ = 0.1 and various levels of excitation, where solid line is stable region and dashed line unstable region, and the dashed-dotted line shows the boundary of the unstable region Figure Legend:

7. Date of download: 9/17/2016 Copyright © ASME. All rights reserved. From: Frequency Tuning of a Nonlinear Electromagnetic Energy Harvester J. Vib. Acoust. 2013;136(1):011010-011010-7. doi:10.1115/1.4025445 Frequency-response curves with constant f = 1 and various levels of damping, where solid line is stable region and dashed line unstable region Figure Legend:

8. Date of download: 9/17/2016 Copyright © ASME. All rights reserved. From: Frequency Tuning of a Nonlinear Electromagnetic Energy Harvester J. Vib. Acoust. 2013;136(1):011010-011010-7. doi:10.1115/1.4025445 Relative velocity response of the oscillator with respect to excitation frequency with different levels of damping under excitation amplitude F = 3 m/s 2 Figure Legend:

9. Date of download: 9/17/2016 Copyright © ASME. All rights reserved. From: Frequency Tuning of a Nonlinear Electromagnetic Energy Harvester J. Vib. Acoust. 2013;136(1):011010-011010-7. doi:10.1115/1.4025445 Relative velocity response of the oscillator in terms of different stretch length of elastic strings with the same initial length l 0 = 100 mm, where solid line is stable region and dashed line unstable region Figure Legend:

10. Date of download: 9/17/2016 Copyright © ASME. All rights reserved. From: Frequency Tuning of a Nonlinear Electromagnetic Energy Harvester J. Vib. Acoust. 2013;136(1):011010-011010-7. doi:10.1115/1.4025445 The relative velocity response for different initial stretch length of elastic strings with the same stretch ratio in linear and nonlinear system Figure Legend:

11. Date of download: 9/17/2016 Copyright © ASME. All rights reserved. From: Frequency Tuning of a Nonlinear Electromagnetic Energy Harvester J. Vib. Acoust. 2013;136(1):011010-011010-7. doi:10.1115/1.4025445 Relative velocity response of linear and nonlinear systems in terms of different excitation amplitudes Figure Legend:

12. Date of download: 9/17/2016 Copyright © ASME. All rights reserved. From: Frequency Tuning of a Nonlinear Electromagnetic Energy Harvester J. Vib. Acoust. 2013;136(1):011010-011010-7. doi:10.1115/1.4025445 The experimental prototype Figure Legend:

13. Date of download: 9/17/2016 Copyright © ASME. All rights reserved. From: Frequency Tuning of a Nonlinear Electromagnetic Energy Harvester J. Vib. Acoust. 2013;136(1):011010-011010-7. doi:10.1115/1.4025445 Experimental setup Figure Legend:

14. Date of download: 9/17/2016 Copyright © ASME. All rights reserved. From: Frequency Tuning of a Nonlinear Electromagnetic Energy Harvester J. Vib. Acoust. 2013;136(1):011010-011010-7. doi:10.1115/1.4025445 The measured average power output (circles) compared with theoretical prediction (solid line) under external excitation F = 5 m/s 2. Graph (a) shows the results for stretch ratio l˜ = 0.85, and Graph (b) for l˜ = 0.96. Figure Legend: