Approximation Algorithms of Crack Growth Rate Curve Based on Crack Size Variations

Abstract

Procedures for obtaining da/dN-ΔK curve on the basis of empirical a-N data were shown. Estimating approaches of crack growth rates for constant, block, variable amplitude, and similar loading were given. Computational methods of equivalent load range ΔPeqv, required for ΔK approximation in case of variable amplitude loading and plotting of a da/dN-ΔK chart, were presented. Advantages and disadvantages of suggested methods were also described. The application of approximation methods for da/dN-ΔK curve determination was imposed in case of constant amplitude loading and for modified SAESUS loading.