Thermal Stress Reduction

	Thermal Stress Reduction in Oxidation-Protective Layers by Surface Geometry Modification Koji Uenishi Department of Aeronautics and Astronautics, The University of Tokyo, Tokyo, Japan

Summary

This study presents a method of reducing the residual stress in the coated layer by introducing a non-flat configuration to the material surface. The model in the analysis consists of a semi-infinite substrate with sinusoidal surface coated by a uniform thickness layer. The two-dimensional elastic problem is analytically solved with non-dimensional parameters: the wave height/length ratio, the coating thickness/wave length ratio, and the elastic moduli ratio of the substrate and the coating. The non-dimensional reduced stresses in the coated layer are graphically described with these parameters. The optimum possible reduction of stress and the corresponding non-dimensional parameters are shown for the elastic moduli ratio. Some numerical examples are given. Related experiments are conducted in order to confirm the effect of stress reduction, using aluminum alloy substrates coated with brittle paint.

Keywords

Coating, Oxidation-protective layers, Residual stress, Thermal stress reduction.

Related Publications

Shioya, T., and K. Uenishi (1995). A Method of Thermal Stress Reduction in Oxidation-Protective Layers by Surface Geometry Modification. In: Proceedings of the 1995 Yokohama International Gas Turbine Congress (Yokohama, Japan, 22-27 October 1995), Vol. III, pp.93-98.
Uenishi, K., T. Shioya, and K. Fujimoto (2010). Effect of Surface Geometry of Substrate on Thermal Stress of Coating. Applied Plasma Science, 18(2), 152-158 (in Japanese).

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