Assessment of residual stresses relaxation in a hardened rotating blade under creep conditions

The method for calculation and estimation of the residual stress in the surface-hardened layer of the rotating blade under creep condition is developed. The base of this method is the hypothesis that the hardened layer has no effect on the structural rigidity (acts as thin film sticked on its surface) and is deformed with it under the outer hard loading. Therefore the calculation of the kinetics of the residual stresses relaxation in the surface layer reduces to the gluing of the two boundary value problems solutions. During the first boundary value problem solving the stress-strain state of the rotating blade under the creep condition is determined without regard to the surface hardened layer. The second boundary value problem shows the researching of the residual stress relaxation in the surface hardened layer, the layer is considered to be the whole, which is deformated under the hard loading with given values of strain components, determined in the first boundary value problem solution.