Session: 26-03 Probabilistic Lifing and Damage Tolerance

Submission Number: 177373

Probabilistic Gas Turbine Rotor Disk Forging Flaw Crack Nucleation Model Based on Short Crack Propagation 

The rotor of a gas turbine is one of the most critical components. Small, hard-to-detect imperfections can be introduced in rotor disks during the manufacturing process, which involves casting an ingot and subsequent forging processes. Cracks can nucleate from these imperfections, also known as forging flaws, which eventually lead to crack propagation and component failure [1, 2]. Therefore, it is essential to quantify reliably the risk of failure for these critical components.

In our previous research, a strong correlation between the forging flaw crack nucleation life and the range of plasticity-corrected stress intensity factor (Δ𝐾𝐽) has been revealed [3, 4]. As part of a series of publications, this work has focused on a physics-based prediction of crack nucleation life. The IBESS approach—which is a fracture mechanics-based prediction of fatigue strength—has been modified and integrated into the modeling of forging flaw crack nucleation. A probabilistic framework has been incorporated into the modeling approach and validated through fatigue tests, including specimens with forging flaws.

References

[1] M. Rezaul Karim, K. Kadau, S. Narasimhachary, F. Radaelli, C. Amann, K. Dayal, S. Silling, and T. C. Germann, "Crack nucleation at forging flaws studied by non-local peridynamics simulations," Mathematics and Mechanics of Solids, vol. 27, p. 1129–1149, 2022.

[2] M. R. Karim, K. Kadau, S. Narasimhachary, F. Radaelli, C. Amann, K. Dayal, S. Silling, and T. C. Germann, "Crack nucleation from non-metallic inclusions in aluminum alloys described by peridynamics simulations," International Journal of Fatigue, vol. 153, p. 106475, 2021.

[3] Y. Yang, C. Amann, I. Varfolomeev, P. Gumbsch, and K. Kadau, "Probabilistic Gas Turbine Rotor Disk Forging Flaw Crack Nucleation Model Based on Experimental Data and Plasticity-Corrected Stress Intensity Factor," in Turbo Expo, 2025.

[4] A. Aydin and I. Varfolomeev, "Development of a crack initiation model for forging defects in rotor steels under cyclic loading," BMWi Energy Research, Project No. 03ET7091G, Report 1317/2021, Fraunhofer IWM, Freiburg, 2021.

Presenting Author: Yanqiao Yang Siemens Energy

Presenting Author Biography: PhD student in probabilistic fracture mechanics.

www.linkedin.com/in/yanqiao-yang-584a24224

Authors:

Yanqiao Yang Siemens Energy
Christian Amann Siemens Energy
Igor Varfolomeev Fraunhofer IWM
Mathis Julian Bellmer Fraunhofer IWM
Peter Gumbsch Fraunhofer IWM
Malek Al-Ameri Siemens Energy
Tuan Duc Nguyen Siemens Energy
Kai Kadau Siemens Energy