Transient Thermal Stresses in Cylinders with a Square Cross Section Under Conditions of Convective Heat Transfer

The transient thermal stresses in a long cylinder with a square cross section resulting from convective heating or cooling by a sudden change in ambient temperature were calculated by the finite element method. On heating, the maximum tensile stresses occur in the center of the rod, whereas the maximum principal stresses occur along the diagonal of the cross section. On cooling, the maximum tensile stresses occur at the center of the faces. The results obtained are discussed in terms of experimental measurement of the thermal stress resistance of brittle ceramics. Possible failure modes during heating and cooling are discussed. Comparison with literature data shows that for a given value of the Biot number the magnitude of the maximum tensile stresses on cooling, in a rod with a square cross section, exceeds those in a rod with a circular cross section.