Thermal Stresses at the Edge of a Bimetallic Thermostat

The plane stress problem of a semi-infinite, bimetallic thermostat subjected to uniform heating or cooling is treated with the theory of elasticity. Solutions to this problem are expressed as the sum of a basic solution for a bimetallic strip of infinite length and a series of complementary solutions. Interlayer peeling stresses at the free edge of the bimetallic thermostat are shown to be singular or nonsingular (but still higher than the nominal values) depending upon whether the combination of the two Dundurs’ bimaterial constants, α (α−2β), are greater or less than zero. In an example problem, current solutions agree well with finite element results while results predicted by a modified beam theory show a large deviation from the other two solutions near the free edge. Boundary layer effects near the free edges of a bimetallic thermostat are also discussed.