Abstract

The mathematical model is constructed on the basis of FE-analysis for evaluation of stress-strain state under a thermal load of substrate – coating system considering non-canonical substrate deformation features. The simply connected thermoelasticity problem is solved for generalized plane strain state in CAE-System SIMULIA Abaqus. Nonuniform distribution of thermal stresses in the system is obtained along the perimeter of the blade profile. Based on cohesive surface technology the technique was developed for calculation of standard and shear contact stress level, initiating an adhesive fracture in the substrate - coating system. The estimation of the required substrate and coating adhesion strength level securing the system integrity under specified operating conditions is proposed. The updating of the obtained results is performed taking into account the coating layer’s irreversible plastic deformations under different temperatures. It’s shown that the appearance of coating inelastic deformations significantly influences on the level of thermal and residual stresses in the whole system as well as contact stress level at the interface substrate – coating initiating adhesive violation. The prognosis of stress level and distribution, as well as adhesive strength in the substrate – coating systems, allow scientifically approaching to the development of coating architecture (chemical and phase layer composition, its number, thickness and formation methods) and significantly decreases the number of experimental tests, their time and costs.

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