Residual Life Prediction for Surface Cracks in Complex Structural Details.

摘要

This paper reports on the development and application of an efficient technique for calculating the residual fatigue life for surface-cracked structures. The analysis treats the major three-dimensional aspects of the surface-crack problem including crack shape (planar crack with crack front curvature) and local stress variation in the structure. The surface crack is modeled with a finite number of shape-degrees of freedom. Necessary stress intensity factor computations are based on the use of a boundary-integral equation (BIE) model of the surface crack, together with an influence function technique for modeling the crack in an actual structure. The combined residual fatigue life method is then employed to predict the life of an actual gas turbine engine disk subjected to flight-by-flight testing in a spin pit.