Design and Fabrication of Micro Centrifugal G-switch
Date Issued
2012
Date
2012
Author(s)
Liu, Huang-Sheng
Abstract
This thesis presents design and fabrication of a micro centrifugal G-switch by ANSYS/LS-DYNA and micro-electrical-mechanical system processing techniques. As the acceleration switch, also called the G-switch, subjected to sufficient levels of axial and centrifugal accelerations, the switch will turn from off to on, delivering signals to the connect circuits which can initiate subsequent processes.
As the G-switch receives acceleration exceeding threshold from surroundings, the proof-mass in the G-switch experiences an inertial force which moves the contact components in touch to trigger output signals. To appropriately investigate the micro centrifugal G-switch, this thesis first designed suitable accelerators and latching mechanism, then simulated numerically the dynamic response of the G-switch subjected to applied impact conditions. As the projectile rotated with a centrifugal acceleration below 1,000 rpm, the installed G-switch was not turned on, staying in a safety mode. The device would be latched up as the spin rate above 2,000 rpm. An additionally axial acceleration impact of 1000G was also applied to the centrifugal G-switch to emulate the launching situation. Numerical results of dynamic response and stress distribution were revealed to evaluate the performances of accelerometers. A novel design of latching mechanism with releasing components was figured out.
Based on the simulated numerical results, this thesis fabricated the micro centrifugal G-switch chips on a silicon-on-insulator (SOI) wafer via MEMS processing. Upon finishing the manufacturing processes, G-switch chips were tested by a centrifugal machine to investigate the performances of the fabricated devices. Test results show that the designed G-switch functioned properly as the acceleration reached the threshold, and all components of the G-switch were in the elastic region of the silicon without destruction. Heating the release mechanisms by applying 1 voltage DC source regulated with series resistors, this latched state was successfully discharged in a short time, fulfilling the purpose of reusing the G-switch.
Subjects
acceleration switch
centrifugal acceleration
impact simulation
MEMS process
release mechanism
Type
thesis
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