Abstract
The increasing demand for highly sensitive, tunable, and affordable micro-flow sensors for applications like morphing wings and unmanned aerial vehicles (UAVs) has driven the development of innovative MEMS-based solutions. This seminar will introduce a new class of flow sensors that operate on the basis of the bifurcation phenomenon observed in double-clamped, initially curved single-crystal silicon microbeams. This sensing principle offers sensitivity and tunability, fundamentally different from traditional flow sensor designs. The core of the sensor is a bistable microbeam, a structure that can rest in two stable states under the same load. This bistability makes the device highly responsive to external stimuli, especially near critical points of stability, known as snap-through and snap-back buckling. The sensor detects changes in the critical "snap-through" voltage—the voltage required to switch the beam between two stable states. This critical voltage is highly sensitive to convective cooling from airflow, which influences the beam's temperature and, consequently, its curvature and mechanical properties. This presentation will also explore a frequency-based sensing method using a single beam. By monitoring the microbeam's resonance frequency, which is also affected by flow-induced cooling and loading, continuous high-resolution measurements can be achieved. For aeronautical applications, these sensors are designed for quick mounting, ensuring non-intrusive integration with the aircraft's skin and minimal flow disturbance. The feasibility and robustness of this concept have been confirmed through laboratory experiments and successful integration into a UAV, demonstrating its potential for advanced flow sensing and flight control. This bifurcation-based approach, driven by nonlinear mechanics, paves the way for a new generation of advanced, integrable, and energy-efficient flow sensors.
About the Speaker
Alexander Liberzon received the B.Sc, M.Sc. and Ph.D. degrees from the Technion–Israel Institute of Technology, Haifa, Israel, in 1996, 1998 and 2003, respectively. He was a Post-Doctoral Fellow at the ETH Zurich, from 2003 to 2006. In 2006, he joined Tel Aviv University, where he is currently a Professor with the School of Mechanical Engineering, heading the Turbulence Structure Laboratory. He is a visiting professor at ETH Zurich, St. Anthony’s Falls Laboratory and University of Toronto. His research interests include MEMS flow sensors and electro-optical experimental techniques for turbulent and complex fluid flow measurements.
Host: Professor Leonardo Chamorro