Thermal loading can produce different thermal strains in the in-plane and through-the-thickness directions in shell structures with orthotropic thermal expansion coefficients. If the structure is curved, this difference causes shell curvature changes and additional stresses.

Classic shell elements do not account for thickness strains and therefore lack the ability to account for the orthotropic thermal expansion effect [1]. Shell element technology that incorporates the thickness strain in the shell curvature calculation is well suited for this type of simulation.