Microstructurally Based Model of Fatigue Initiation and Growth
Abstract
A model to calculate fatigue life is developed based on the assumption that fatigue life is entirely composed of crack growth from an initial microstructural inhomogeneity. Specifically, growth is considered to start from either an ellipsoidal void, a cracked particle, or a debonded particle. The capability for predicting fatigue life from material microstructure is based on linear elastic fracture mechanics principles, the sizes of the crack-initiating microstructural inhomogeneities, and an initiation parameter that is proportional to the cyclic plastic zone size. A key aspect of this modeling approach is that it is linked with a general purpose probability program to analyze the effect of the distribution of controlling microstructural features within the material. This enables prediction of fatigue stress versus life curves for various specimen geometries using distributional statistics obtained from characterizations of the microstructure. Results are compared to experimental fatigue data from an aluminum alloy.
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 07, 1994
- Accession Number
- ADA278198
Entities
People
- A. J. Hinkle
- J. R. Brockenbrough
- P. E. Magnusen
- R. J. Bucci
Organizations
- Alcoa