Fatigue mechanisms and subsequent crack growth represent the predominant causes of fracture failures in gas turbines. Investigating fatigue crack growth and the fracture behavior of critical gas turbine components is essential for predicting and extending their service life. The paper aims to discuss this issue.
Fatigue crack growth tests were conducted on gas turbine combustor liner materials between 500 °C and 860 °C to determine high-temperature crack growth rates. Testing employed a sinusoidal waveform at 10 Hz with a stress ratio of R = 0.1 and a maximum load of 8000 N. Three-dimensional crack growth was simulated using the Paris law with a linear elastic constitutive model, while fracture behavior was evaluated via the J-integral under an elastoplastic framework, considering different start-up conditions (hot, warm and cold starts).
The results indicate that, under the given conditions, the combustor liner exhibits the shortest service life during cold starts, only 24.45% of warm start values and a mere 1.14% of hot start conditions, primarily due to the maximum stress intensity factor range. The crack growth rate is relatively slow near the inner surface but accelerates significantly near the outer surface. This phenomenon occurs because the initial crack at the dilution hole edge experiences compressive stress on the inner surface and tensile stress on the outer surface.
Based on these findings, this study recommends structural reinforcement of the combustor liner's outer surface to improve durability and operational safety under various start-up conditions.
A series of fatigue crack growth tests are performed on Haynes 230 at 500 °C, 700 °C, 800 °C, and 860 °C.
The accuracy and reliability of the co-simulation method utilizing Abaqus and Zencrack are validated.
The simulated critical locations and corresponding crack growth paths show strong agreement with experimental observations.
Under cold start conditions, the crack growth rate reaches its maximum, and the remaining fatigue crack growth life is minimized.
As the crack progressively extends, the outer surface region becomes the primary critical zone for crack growth.
