A5103200370- Mechanical and Optical Resonators
- Vibration and Dynamic Analysis
- Force Microscopy Techniques and Applications
- Probabilistic and Robust Engineering Design
- Structural Health Monitoring Techniques
- Nonlinear Dynamics and Pattern Formation
- Advanced MEMS and NEMS Technologies
- Vibration Control and Rheological Fluids
- Nonlinear Photonic Systems
- Near-Field Optical Microscopy
- Geophysics and Sensor Technology
- Bladed Disk Vibration Dynamics
- Acoustic Wave Phenomena Research
- Fault Detection and Control Systems
- Dynamics and Control of Mechanical Systems
- Advanced Thermodynamics and Statistical Mechanics
- stochastic dynamics and bifurcation
- Composite Structure Analysis and Optimization
- Innovative Energy Harvesting Technologies
- Scientific Research and Discoveries
- Seismic Performance and Analysis
- Structural Response to Dynamic Loads
- Combustion and flame dynamics
- Gyrotron and Vacuum Electronics Research
- Fluid Dynamics and Vibration Analysis
University of Illinois Urbana-Champaign
2014-2025
Drexel University
1996-2017
University of Illinois System
1989-2016
IBM Research - Thomas J. Watson Research Center
2004
Marymount University
1998
University of Connecticut
1993-1996
Naval Aeronautical and Astronautical University
1985
Our focus in this study is on experimental investigation of the transient dynamics an impulsively loaded linear oscillator coupled to a lightweight nonlinear energy sink. It shown that seemingly simple system exhibits complicated dynamics, including beating phenomena and resonance captures. also demonstrated that, by facilitating targeted transfers sink, significant portion total input can be absorbed dissipated oscillator.
A method for analyzing the free vibration of combined linear undamped dynamical systems attached at discrete points is shown. The uses separation variables to exhibit harmonic motion system and derive a generalized differential equation normal modes. Green's functions vibrating component are used solve characteristic natural frequencies system. can then be solved exact demonstrated two types involving beams oscillators. For particular systems, approximate determined through Galerkin's finite...
A nanomechanical resonator incorporating intrinsically geometric nonlinearity and operated in a highly nonlinear regime is modeled developed. The nanoresonator capable of extreme broadband resonance, with tunable resonance bandwidth up to many times its natural frequency. Its drop frequency (the upper jump-down frequency) are found be very sensitive added mass energy dissipation due damping. We demonstrate prototype mechanical integrating doubly clamped carbon nanotube show over tens MHz...
This work studies theoretically and experimentally acoustic non-reciprocity in a nonlinear asymmetric 1D vibro-acoustic system, featuring two dissimilar waveguides coupled through vibrating membrane, connected by four cavities. The large-amplitude membrane vibrations induce strong stiffness nonlinearity, while the unequal lengths of different volumes cavities introduce asymmetry. Hence, prerequisites for passive break reciprocity are satisfied this system. A reduced order model (ROM) is...
During dynamic atomic force microscopy (AFM), the deflection of a scanning cantilever generates multiple frequency terms due to nonlinear nature AFM tip-sample interactions. Even though each term is reasonably expected encode information about sample, only fundamental typically decoded provide topographic mapping measured surface. One main reasons for discarding higher harmonic signals their low signal-to-noise ratio. Here, we introduce new design concept multi-harmonic AFM, exploiting...
We measure the infrared spectra of polyethylene nanostructures height 15 nm using atomic force microscope spectroscopy (AFM-IR), which is about an order magnitude improvement over state art. In AFM-IR, light incident upon a sample induces photothermal expansion, measured by AFM tip. The thermomechanical response sample-tip-cantilever system results in cantilever vibrations that vary time and frequency. A time-frequency domain analysis vibration signal reveals how dynamics affect AFM-IR...
Nonlinear mechanical systems promise broadband resonance and instantaneous hysteretic switching that can be used for high sensitivity sensing. However, to introduce nonlinear resonances in widely microcantilever systems, such as AFM probes, requires driving the cantilever an amplitude is too large any practical applications. We a novel design with strong nonlinearity at small oscillation arising from geometrical integration of single BN nanotube. The dynamics system was modeled theoretically...
A prototype nonlinear energy sink, whose design is based upon parameters determined to effectively suppress transonic aeroelastic instabilities of a wind-tunnel wing model (denoted as generic transport wing) via passive targeted transfer, introduced. The lightweight sink mounted within low-profile winglet, which attached the tip wing. In addition, safety features and measurement hardware have been built in facilitate future experiment. effects on structural dynamics are demonstrated ground...
Atomic force microscope infrared spectroscopy (AFM-IR) can perform IR spectroscopic chemical identification with sub-100 nm spatial resolution, but is relatively slow due to its low signal-to-noise ratio (SNR). In AFM-IR, tunable laser light incident upon a sample, which results in rise temperature and thermomechanical expansion of the sample. An AFM tip contact sample senses this nanometer-scale photothermal expansion. The motion induces cantilever vibrations, are measured either terms...