Application of Smart Materials to Improve the structural Performance

Abstract

Advanced structural systems are required to have specific functions associated with operating environments. For the purpose of realizing these functions of smart structures, many research activities have been performed. Functional materials and their characteristics, analysis method of smart structures, sensor and actuator placement, controller design, and many other relevant topics have been studied. This article introduces some analytic and experimental research on the application of smart materials, especially shape memory alloys (SMAs), optical fiber, and piezoelectric materials. The numerical analysis of the thermomechanical responses of the structures with initial strained SMA layer has been performed. For the numerical simulation in this research, the incremental formulation of the 3-D SMA constitutive model is used to predict the thermomechanical responses of SMAs. The unique SMA responses such as pseudoelasticity and the shape memory effect are investigated by using finite element procedure. The actuation force applied by SMA layer is used to suppress the deflection induced by thermal buckling of the host structure. In addition, the controllable recovery force or displacement of the SMA strip placed on host structure is used to modify or control the host structural shape. Also, the application of fiber optic sensor, extrinsic Fabry-Perot interferometer (EFPI) and fiber Bragg grating (FBG) sensors has been investigated. The dynamic sensing characteristics of fiber optic sensors were explored and the vibration measurement and suppression of composite structures have been performed. In addition, the stability boundary characteristics and the suppression of dynamic aeroelastic instability have been investigated utilizing piezoceramic actuators and adaptive controller. It is expected that more realistic functions of smart composite structures can be developed and the multi-functional smart structures can be realized. (author abst.)