SUBJECT: Ph.D. Proposal Presentation
   
BY: Michael Rouleau
   
TIME: Tuesday, October 4, 2022, 12:30 p.m.
   
PLACE: MRDC Building, 2405
   
TITLE: Nonlinear Dynamics of Bistable Systems: Impact Excitation, Parametric Excitation, and Small-Scale Effects
   
COMMITTEE: Dr. Julien Meaud, Chair (ME)
Dr. Michael Leamy (ME)
Dr. Alper Erturk (ME)
Dr. Chengzhi Shi (ME)
DR. George Kardomateas (AE)
 

SUMMARY

Systems including one or more bistable mechanical systems, which exhibit two stable equilibria, have been under extensive research in recent years. Within this literature, a variety of excitations have been investigated. However, gaps in literature hamper many practical applications such as nano-scale mechanical switches for sensing or computing.
This dissertation work focuses on filling these gaps via a series of investigations into the fundamental nonlinear dynamics of bistable systems.
First, a completed investigation details the dynamics of a bistable system subjected to impact forcing, primarily through analytic derivation and numerical simulation. Rich
chaotic and periodic dynamical behavior is observed, including intrawell and interwell responses. Experimental validation is also provided. Next, ongoing work extends this
impact-based excitation study using a continuous buckled beam. Numerical simulations again follow an analytic derivation. Development of experimental protocols provides opportunity for validation of the continuous numerical model. Finally, future work is proposed to be completed as part of this dissertation. Specifically, the response types of a pendulum subjected to parametric excitation are investigated. In addition, a small-scale bistable system is used to explore the influence of physics such as electro-static and adhesive interactions which typically must be considered at the μm scale and below for applications including micro-electro-mechanical system(s) (MEMs) and nano-electro-mechanical system(s) (NEMs). Modeling and experimental opportunities for each are described.