Distributed Control of Nonlinear Aircraft Structures Including Aerodynamic and Temperature Interactions

Abstract : Imposed shape changes and surface control of flexible structures can offer many aerodynamic advantages in flight maneuverability and precision control. Largely deformed shapes and surfaces often involve nonlinear deformations. Studies on the control of nonlinear behavior related to the deformed surfaces and shape changes would provide detailed information for future controlled surface design and implementation. This research is concerned with the controlling nonlinearly deformed structures, e.g., various shells and flexible wings, based on the smart structures technology. Distributed sensing/actuation, thermoelectromechanical/control equations and boundary conditions including elastic, temperature, and piezoelectric couplings are derived and applied to distributed sensing/actuation and control of various nonlinear and linear aerospace structures and components made of shells and plates. Analytical solutions are compared with experimental data and for finite element solutions. A new finite element code, consisting of nonlinear/linear piezothermoelastic shell and hexahedral elements, is developed and applied to various nonlinear/linear aerospace structures with or without temperature excitations. Active control of imposed shape changes, nonlinear flexible deflections, thermal deformations, natural frequencies, and dynamic responses using distributed piezoelectric actuators are studied, and their nonlinear effects evaluated.