Risk estimation for LCF crack initiation

TL;DR

This paper introduces a new probabilistic method for estimating the risk of crack initiation due to low-cycle fatigue in turbomachinery components, incorporating inhomogeneous stress fields and size effects.

Contribution

It develops a failure-time process-based approach implemented as a finite-element postprocessor for more accurate fatigue risk assessment.

Findings

Effective in modeling crack initiation risk in gas-turbine disks

Incorporates inhomogeneous stress fields and size effects

Demonstrates applicability through a compressor disk example

Abstract

An accurate risk assessment for fatigue damage is of vital importance for the design and service of today's turbomachinery components. We present an approach for quantifying the probability of crack initiation due to surface driven low-cycle fatigue (LCF). This approach is based on the theory of failure-time processes and takes inhomogeneous stress fields and size effects into account. The method has been implemented as a finite-element postprocessor which uses quadrature formulae of higher order. Results of applying this new approach to an example case of a gas-turbine compressor disk are discussed.