Collaborative Research: Nonlinear Electromechanical Dynamics for Ultra-Sensitive Gas Detection and Autonomous Actuation

This collaborative research project will advance the fundamental understanding of nonlinear dynamics in electromechanical systems that can convert a weak physical stimulus into a decisive mechanical response. The work is motivated by the need for compact low-power devices that can detect hazardous conditions and respond without complex external electronics. By studying how instability, resonance, and switching can be intentionally harnessed, the project seeks to establish new principles for autonomous physical warning systems. Hydrogen and carbon dioxide systems are used as representative case studies to experimentally demonstrate these nonlinear dynamical principles in physically distinct settings. The resulting principles may enable monitoring and warning technologies for advanced manufacturing facilities, hydrogen-based energy systems, environmental monitoring, and biomedical applications. Hydrogen detection is important for the safe operation of emerging energy and manufacturing infrastructure, while carbon dioxide monitoring plays important roles in biotechnology, respiratory monitoring, and medical diagnostics. By investigating how nonlinear dynamical systems can transform detection directly into physical action, the project will establish new approaches for integrating sensing, decision-making, and response within compact autonomous platforms. The project will also contribute to the education and training of students in dynamics, microsystems, and interdisciplinary engineering. The technical thrust of the project is to investigate how dynamic pull-in, buckling, multi-frequency excitation, and coupled electrical and mechanical resonances interact to create highly amplified and autonomous dynamical responses in electrostatically actuated microsystems. A central objective is to establish the fundamental dynamics governing a two-stage amplification process in which small perturbations first induce large response changes through simultaneous electrical and mechanical resonances and then trigger dynamic pull-in instabilities that convert sensing directly into mechanical action. The research will develop analytical and computational models to characterize nonlinear resonances, bifurcations, basin evolution, escape dynamics, and stability boundaries in these strongly coupled electromechanical systems. Continuation methods, shooting techniques, and experimental validation will be employed to identify operating regimes that maximize amplification, sensitivity, robustness, and repeatability. The investigation will also examine how buckling-induced nonlinearities and multi-frequency excitation influence resonance interactions and instability thresholds. Experimental demonstrations involving hydrogen detection through stiffness-related thermal-conductivity effects, and carbon dioxide detection through adsorption-induced mass loading will provide representative platforms for validating the developed theories. In the final phase, the project will explore how these nonlinear dynamical phenomena can be combined to realize logic-gate-like behavior and autonomous warning functions, establishing new principles for integrating sensing, decision-making, and actuation within a single electromechanical system. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.