Analytical Localized Thermo-Mechanical Analysis of Bi-Material Thermostats using the Full Layerwise Theory

摘要

Thermo-mechanical properties of materials enable the designers to construct thermal-sensitive structures as actuators to perform a pre-defined function or as sensors to control an operation. A bi-material thermostat is a common sample of this kind of structures which senses the change of temperature as it deforms. Bi-material thermostats are made of two strips of different materials joined together, and sense the temperature changes by their asymmetrical deformation. Since the bonding specifications can significantly affect the strength of the bond-line in thermostats, one of the most important aspects in constructing an appropriate thermostat is to determine the interlaminar stress distributions produced interior its bonding region. In this manner, designers might be able to evaluate the strength of the bond-line of the thermostat and the temperature ranges it can endure. Moreover, it should be noted that the localized thermal effects caused through temperature changes have highly intensive influences on the bonding strength particularly near the edges of bond-line, where the edge effects make considerable increases in localized stresses, and as a result, the strength of the bond-line may decrease. This paper presents accurate analytical solutions for the interlaminar stress distributions interior the bond-line and especially near its edges within the framework of the full layerwise theory provided for a bi-material thermostat. The solutions presented for some thermal loading and geometrical conditions are validated via analytical and numerical results available in the literature.