Ph.D Thesis

Ph.D StudentAbu-Salih Samy
SubjectModeling and Analysis of Electromechanical Buckling with
Application to Novel MEMS Devices
DepartmentDepartment of Mechanical Engineering
Supervisor PROF. David Elata


ElectroMechanical Buckling (EMB) is the bifurcation response which results from the coupling of electromechanical bifurcation and mechanical buckling. The work presented here is seemingly the first time ever this coupling is considered and analyzed. This work also includes a first ever experimental validation of EMB.

Mechanical buckling occurs in slender structures that are subjected to an axial compressive load which is larger than a critical value. In this dissertation it is shown that an electrostatic field can instigate buckling even when the compressive load is below the critical value. The EMB voltage is a monotonically increasing function of the axial load. Motivated by this, a novel method for measuring residual stress in micro-structures is presented. This method enables to measure compressive as well as tensile stresses, in a continuous wide range.

The EMB response of a pre-stressed slender microbeam that is bonded to a linear elastic foundation and is subjected to electrostatic forces is also investigated. In this dissertation it is shown that the EMB of such a microbeam can be used to achieve reversible, electrostatic on/off switching of surface flexures.

In this work, the electromechanical buckling and postbuckling of a circular cylindrical micro shell that is subjected to a radial axi-symmetric electrostatic force is also investigated. It is found that the initial electromechanical postbuckling of such a micro shell is unstable for the range of parameters considered.