Open Access

ARTICLE

Integrity of Thermal Actuators using the Concept of Energy Density

by ,

1 Department of Applied Sciences, Technical University of Crete, Chania, Greece.

Structural Durability & Health Monitoring 2007, 3(1), 29-34. https://doi.org/10.3970/sdhm.2007.003.029

Abstract

Actuators are structures that give micro-electro-mechanical systems (MEMS) the ability to interact with their environment rather than just passively sensing it. Recent studies of MEMS thermal micro-actuators have shown that simple in design and production devices can provide deflection of the order of 10 μm at low voltages. Recently, metals and single-crystal silicon materials were included in the range of materials used for thermal actuators since they operate at lower temperatures than the commonly used (poly)silicon devices. These actuators are liable to meet the loads in service, so the corresponding integrity and stability analysis constitutes a topic of interest on which researchers have reported many significant results. Of concern are the group of homogeneous actuators, in which a temperature difference is set between the two thermal bimorph arms that are vulnerable to cracking at the micro-, meso- and macro-scale levels. The main objective of this work is to examine how, when and where failure would occur necessitates the simultaneous description of failure initiated locally and terminated globally. Up to this date, one of the most known theories used to address sub-critical and critical fracture simultaneously is the strain energy density concept. In this work potential failure sites are determined with consideration given to the influence of load, geometry and voltage potential with the use of the local and global peaks and valleys of the strain energy density distribution estimated after a finite element analysis.

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Keywords

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