Papers by Author: Algimantas Bubulis

Abstract: Special fixing devices have been developed for fixing articles. With the use of external fields, they allow one to realize reversal fixing of articles made from both metal and dielectric materials. The present investigations were aimed at creating controllable materials for fixing articles of electronic engineering and at developing efficient devices for the technology of vibrotesting.

Abstract: Components of navigating devices can be affected by acoustic emission and vibration. Therefore prototype samples and electronic components must be tested in such conditions. Heterostructures, which destructed under the action of external physical factors and kinetics of formations of porous defects in silicon substrates, were analyzed.

Abstract: This article deals with automatic balancing (self-equalizing) of rotors with vertical axis of rotation by means of liquid. There used to be a statement claiming that automatic balancing was possible only after first critical (above resonance) rotation zone of rotors. However in 1995 the phenomenon of automatic balancing with liquid in both below resonance zone of rotor rotation and in the resonance itself was registered using the method of high speed video shooting. The paper suggests theoretical explanation of the phenomenon stated by means of carried out experiments.

Abstract: Electrostatic microswitch and its fabrication technology have been developed for the first time in Lithuania, at Kaunas University of Technology (KTU). The microdevices were produced by using a nickel surface micromachining process. The microswitch consists of a cantilevered nickel structure suspended over the bottom electrodes. The width of the structure is 30 μm, thickness - 2 μm and length ranges from 67 to 150 μm. Implementation of microswitches as a substitute for the present solid-state switching devices poses many problems. In particular higher actuation voltages, lower switching speed and a reduced lifetime are considered to be among the most significant ones. With the aim of improving these parameters a finite element model is currently developed that takes into account not only microscale-specific electrostatic actuation and air damping effects but also includes the bouncing phenomena. Experimental studies of electrical and dynamic characteristics were also carried out with the purpose of model validation and correction. The paper presents initial results of theoretical modal and air damping analysis as well it shows the first attempts to measure vibration modes of the cantilever structure of the microswitch using Laser Doppler vibrometer.