Probabilistic Analysis of LCF Crack Initiation Life of a Turbine Blade under Thermomechanical Loading

TL;DR

This paper extends probabilistic methods to analyze fatigue crack initiation life in turbine blades under complex thermomechanical loading, incorporating non-constant temperature effects for improved accuracy.

Contribution

It introduces an extended probabilistic approach with finite element implementation for assessing fatigue life under variable thermal and mechanical conditions.

Findings

Method successfully applied to a gas-turbine blade example.

Enhanced accuracy in fatigue life prediction under thermomechanical loading.

Provides a practical tool for turbine blade design and safety assessment.

Abstract

An accurate assessment for fatigue damage as a function of activation and deactivation cycles is vital for the design of many engineering parts. In this paper we extend the probabilistic and local approach to this problem proposed in [1,2] and [3] to the case of non-constant temperature fields and thermomechanical loading. The method has been implemented as a finite element postprocessor and applied to an example case of a gas-turbine blade which is made of a conventionally cast nickel base superalloy.