VEH

1. Design and Development of Effective Nonlinear Energy Harvesters
Yuan Li; Supervisor: Yeping Xiong
Faculty of Engineering and the Environment, University of Southampton, UK.
yl16e10@soton.ac.uk; y.xiong@soton.ac.uk
Fluid Structure Interactions Research Group
FSI Away Day 2012
Background
• Ambient energy
harvesting is also
known as energy
scavenging or power
harvesting, and it is
the process where
energy is obtained
from the environment.
• The fundamental idea
is to convert ambient
energy sources or
waste energy into
usable electricity.
Objectives
• Investigate nonlinear energy flow equation of an oscillator
with linear damping to analyze the effect of its smoothness
parameter on power transfer of the nonlinear system.
• Investigate the coupling effect of nonlinear damping and
nonlinear stiffness on energy harvesting.
• Analyze nonlinear energy transmission mechanisms of the
nonlinear oscillator and the effects of super-harmonic
resonance or combination resonances.
• Design a model of the oscillator to do corresponding
dynamic experiments to evaluate the effect of the
nonlinear parameters on the power harvested.
This project aims to investigate a new nonlinear energy
harvesting system to explore novel energy harvesting
mechanism and develop an effective nonlinear energy harvester
for applications in maritime engineering.
• Currently, almost all the commercial applications so far is
the time-invariant nature of the environment in which the
harvester operates, i.e., the frequency spectrum of the
excitation is stationary with respect to time. This limitation
is primarily due to the use of linear mechanical resonators.
Figure 1. A 1.0×2.25-inch
piezoelectric generator for vibration
energy harvesting. [2]
References:
[1] http://www.oceanpowertechnologies.com/res.htm
[1] R. Murray, J. Rastegar, Energy-harvesting power sources for a wide range of
applications, SPIE Newsroom , 2007.
[2] http://www.enocean.com/en/enocean_modules/eco-200/
Figure 2. A Energy converter for
motion energy harvesting [3]
• This study is motivated by a growing recent interest in new
energy source in terms of vibration energy harvesting.
• Nonlinear oscillator has great potential to enhance power
transfer as nonlinear interactions may give rise to a broad-
band frequency response or multiple resonance peaks and
thus increasing the range of effective functions.
Aim
Nonlinear Oscillator
Methodology
Power flow analysis provides an effective technique to describe
the dynamic performance, accounting for both force and motion
characteristics, of any types of systems. This method is based
on the universal principle of energy balance and conservation to
investigate dynamic systems. It has been proved that power
flow approaches can be successfully developed to model
complex structures and applied to vibration control in both
linear and nonlinear systems. This approach will be used to
evaluate the vibration energy harvesting efficiency.
An nonlinear oscillator system provides adjustable nonlinearity will
be investigated first. This system consists of a mass m linked by two
inclined elastic springs. Each spring of stiffness k is pinned to a rigid
support. The nonlinearity of this oscillator can be smooth or
discontinuous depending on the value of the smoothness parameter.
Various of energy generation units, e.g. piezoelectric unit and
electromagnetic unit, can be attached on the oscillator to harvest
energy from vertical motion.
Figure 1. A floating wave energy
harvester. [1]
Figure 2. The total energy containing in
waves equals to twice of the world’s
electricity production. (World Energy
Council) [1]