Papers by Author: Jae Hung Han

Abstract: This paper demonstrates the feasibility of using piezoelectric actuators in controlling flow-induced vibration of a lightweight composite wing structure. Vibration characteristics of the composite wing model were predicted analytically against the air flow speed and the results were compared with experimental results from wind tunnel tests. Vibration control tests were successfully accomplished using positive position feedback (PPF) controller and the real-time operating deflection shapes of the composite wing were measured using 3D optical motion capture system.

Abstract: The ionic-polymer-metal-composite actuators can easily actualize the bio-mimetic fish-like locomotion owing to their best merit for large deformation. And novel fabrication methods of IPMC patterned with multiple electrodes were developed to apply the different driving waves to the multiple electrodes. Generally, the IPMC actuator has been fabricated in electroless plating technique, while it is high time-consuming process, showing poor repeatability in the actuation performance due to the variables in the process of fabrication. Therefore the several fabricating methods was newly investigated by combining electroless plating, photolithography, physical sputtering and electroplating techniques capable of precisely patterning and actuating of the multiple electrodes. On the whole, four different methods were compared and analyzed in similar thickness level of Platinum electrodes. Consequently, the mixing the electroless chemical reduction and electroplating can be a promising candidate for the low time-consuming method and the better bending performance.

Abstract: The thermomechanical behavior of SMA thin film actuator and their application are investigated. The numerical algorithm of the 2-D SMA thermomechanical constitutive equation is developed using user material (UMAT) subroutine written by FORTRAN. For the numerical results of SMA thin film, the ABAQUS finite element program has been utilized with UMAT subroutine of the numerical algorithm of SMA. The application of SMA thin film for the membrane pump actuator is demonstrated.