The use of theories to determine mechanical and thermal stresses in monolithic, coated and multilayered materials with stress-dependent elastic modulus or gradient in elastic modulus exemplified for thermal barrier coatings

An analysis of the stress, strain and curvature resulting from mechanical or thermal loading for a material with stress-dependent elastic modulus or gradient in elastic modulus is presented. Consideration is given to the effects of external loads and moments, the mismatch in thermal expansion and temperature gradients. The relationships can be used to determine the unknown elastic modulus, thickness, thermal expansion coefficient or thermal gradient or to calculate stresses, strains and curvature if the properties are known. As an example for the use of the presented relationships literature results on four-point bending of free-standing and the thermo-elastic bending of bonded thermal barrier coatings (TBCs) are reanalysed.