Key factors and methods used to calculate the aeroengine turbine blades' creep and fatigue life.

Key factors and methods used to calculate the aeroengine turbine blades' creep and fatigue life.

Creep Life Calculations

Method/Model	Description	Key Factors
Norton's Creep Model	Predicts creep strain rate based on stress and temperature.	Material constants, temperature, stress.
Lemaitre-Chaboche Damage Model	Accounts for progressive damage under cyclic loading.	Material properties, stress cycles.
Larson-Miller Parameter	Correlates temperature and stress with rupture time for long-term creep predictions.	Temperature, stress, material properties.
Finite Element Analysis (FEA)	Simulates thermal and mechanical stresses to evaluate damage evolution.	Blade geometry, cooling effectiveness, operational conditions.

Fatigue Life Calculations

Method/Model	Description	Key Factors
Manson Formula	Estimates low-cycle fatigue life based on strain amplitude and cycles.	Strain amplitude, number of cycles.
Creep-Fatigue Interaction Models	Predicts the combined effects of creep and fatigue.	Material properties, operational cycles, temperature.
Johnson-Weibull Analysis	Uses field data to estimate blade life based on historical failure modes.	Operational history, failure data.

Key Factors Influencing Life Calculations

Factor	Description
Operating Conditions	Temperature, stress levels, operational cycles.
Material Properties	Thermal conductivity, strength, creep resistance.
Cooling Effectiveness	Reduces thermal stresses and extends blade life.
Design Parameters	Blade geometry and cooling system design influence stress distributions.