Friday, October 24, 1997, 1:00 p.m.

Gregory P. Carman
MANE Department, University of California at Los Angeles

Active Material Systems and Meso-Scale Actuator Designs

Active (smart) materials and Micro-Electro-Mechanical Systems (MEMS) are now focal points for a variety of research and development activities due to the exceptional promise these systems offer. For example, researchers report active control flaps applied to the blade of a rotorcraft significantly reduce the vibrational loads imparted to the hub and, active flow control concepts (including MEMS based concepts) delay stall and decrease drag. While these and other studies indicate the potential advantage for structures containing active materials and MEMS components, fundamental issues such as inadequate force, displacement and bandwidths are inhibiting their use in a broad range of applications. To address these concerns my group conducts experimental studies to understand a materials response to combined electro-magneto-thermo- mechanical loading in the context of designing mechanical structures. To extrapolate the discrete experimental data generated during these tests to other loading regimes, we develop novel nonlinear analytical models that incorporate the complex coupling (also domain motion) arising between combined fields. These mathematical tools provide an avenue to circumvent the expensive "make-it-break-it" approach for designing adaptive structures. In this presentation I will provide an overview of the research work being conducted at UCLA on these topics. The presentation will primarily focus on the experimental/ analytical results obtained an ongoing project funded by the Army Research Office. A novel meso-scale actuator device combining piezoelectric materials with MEMS components is being fabricated to produce a large force displacement actuator. The new actuator is intended for use on a rotorcraft system to reduce vibration, minimize blade vortex interactions, and alleviate dynamic stall.