An experimental approach to nanomechanical buckling and snap-through phenomenon
Author
Hatipoğlu, Utku
Advisor
Hanay, Mehmet Selim
Date
2019-09Publisher
Bilkent University
Language
English
Type
ThesisItem Usage Stats
164
views
views
59
downloads
downloads
Abstract
Buckling has received little attention as a valuable resource for engineering applications
since it is regarded as a type of failure in civil and mechanical engineering.
Nevertheless, buckling has a great potential in nanoelectromechanical
systems(NEMS) field as a bistable process that has rich and complex dynamics.
Here, we explore post buckling dynamics of a nano-beam experimentally by
employing various probing techniques. By employing an all-electronic architecture,
we precisely control the buckling amount as well as buckling direction of
the nano-beam which eventually gives us the ability to control a two-level mechanical
system with high precision and speed. A full control over the potential
energy landscape of the system is demonstrated with different techniques such as
Scanning Electron Microscopy operated in three different modes and microwave
coupling method. During proof of concept experiments, left and right buckling,
large deflection buckling, nonvolatility – which is an indication of pure bistable
states – and snap-through phenomenon is demonstrated. Further steps of the
study focused on the snap-through phenomenon that is the interstate transitions
of the buckling beam after bifurcation. During these experiments, more involved
relations are investigated such as mechanical bias and effect of plastic deformation
as well as the effect of actuation scheme on interstate jumps. Moreover, to
obtain a better grasp of post-buckling dynamics, quantitative measurements are
carried out which reveal the reaction speed of the system and time scale of interstate
jumps. Lastly, oscillatory snap-through motion is observed in some special
conditions that can be beneficial to understand noise dynamics of the system and
it has a potential to contribute energy harvesting applications.
Keywords
BucklingPost-buckling
Nanoelectromechanical systems
NEMS
Snap-through
Bistability
Two-level system