Vibration Analysis of U-Shaped Beam Electrothermal Microactuators
This paper presents an analytical model for the vibration analysis of a U-shaped electrothermal microactuators. A U-shaped electrothermal microactuator has a unique geometrical structure which consist of, interconnected multiple thick and thin beam segments. In this proposed model, both the longitudinal and lateral deflections of each beam segment are incorporated. To facilitate the modelling process, a thick beam is replaced by the thin beam segment using the artificial Young's modulus and density so that the deformation and inertia force of the thin beam can be used to equivalently describe that of the thick beam segment. The relationship of the force and deflections in both longitudinal and lateral directions at connected points between adjacent beam segments is formulated with continuity conditions. The frequency equation is then established subjected to two both boundary and continuity conditions. Solving the frequency equation yields the natural frequencies of the U-shaped beam actuator. The analytical results are compared with the finiteelement simulation results using ANSYS software. A good agreement is observed between analytical and simulation data, and hence the proposed vibration analysis model is verified. This model provides the first insight study on the vibration analysis of U-shaped electrothermal actuators, which is essentially crucial to dynamic system modelling, control, and dimension optimizations.
Design and Analysis of Electro thermally Actuated Microgripper
Micro-Electro-Mechanical Systems (MEMS) technology offers the opportunity to produce mechanical, electromechanical, and electrochemical devices with the same unprecedented levels of miniaturization, and functionality as modern Very Large Scale Integrated (VLSI). Micro grippers are used for manipulation of biological samples, for assembling of micro parts and for micro assembly. Electro thermal micro grippers are promising tools enabling assembly and manipulation of nano-scale structures. In this paper MEMS based U-shaped thermally actuated micro-gripper is designed using two hot and one cold arm type thermal actuator. Then the effect of coefficient of thermal expansion and poisson’s ratio on stress for thermally actuated micro-gripper is analyzed and the results shows that the stress increases with the increase in coefficient of thermal expansion and the stress decreases with the increase in poisson’s ratio.
Frequency selective surface design for blinds applications
In this paper, the reconfigurable blind structure with frequency selective surfaces(FSS) for the building applications are presented. Frequency transmission characteristics for different angles of the proposed blind-FSSs are investigated and verified through simulation and measurement. The simulation results show that we can implement the reconfigurable blind-FSS for multiband wireless applications. To verify the proposed paper, two kinds of blind-FSSs, crossed dipole FSS and circular ring FSS are fabricated and measurements are performed for different angles. The proposed structure in this paper which is very simple, can be easily applied to any planar surface for wireless security applications at low cost.