Improving the Transient Thermal Fatigue Life of a Gas Turbine Casing by Drilling Stop Holes and Inserting Pins into Them

Document Type : Research Article


Department of Mechanical Engineering, University of Zanjan, Zanjan, Iran


Gas turbines casings are susceptible to cracking at the edge of the eccentric pin hole. This
paper describes the improvement of the transient thermal fatigue life of gas turbines casings through the
application of pins. The repair technology under consideration involved drilling a number of holes in
the gas turbines casing along the crack and inserting pins into them. The crack position and direction
were determined using non-destructive tests. A series of finite element models were developed and
tested in AStM-A395 elastic-perfectly plastic ductile cast iron. In some specimens, holes were drilled
near the crack tips. Pins were inserted into the holes in some cases. Abaqus software finite element
package and Zencrack fracture mechanics code were used for modeling. The efficiency of crack repair
by the installation of pins was investigated along with the effect of the number of pins on crack repair
efficiency. The result shows that the insertion of pins into holes drilled in the vicinity of the crack tips is
an effective method of retarding crack growth in a gas turbine casing.


[1] P. Alto, Blade Life Management System for GE Frame 6B Gas Turbines, EPRI, 1998.
[2] P. Mestanek, Low cycle fatigue analysis of last stage steam turbine blade, Applied and Computational Mechanics, 2 (2008) 71-82.
[3] K. Cheong, A.D. Karstensen, Integrity assessment of an embrittled steam turbine casing, Int J Press Vessels Pip, 86 (2009) 265-272.
[4] E. Poursaeidi, A. Kavandi, K. Vaezi, M.R. Kalbasi, A. Mohammadi, Fatigue crack growth prediction in a gas turbine casing, Eng. Fail. Anal, 44 (2014) 371-381.
[5] B. Mariusz, On-line monitoring and control of thermal stresses in steam turbine rotors, Applied Thermal Engineering, 94 (2016) 763-776.
[6] C. Bao, Analysis of thermal stress and fatigue fracture for the solar tower molten salt receiver, Applied Thermal Engineering, 99 (2016) 741-750.
[7] Q. Wang, Y. Wang, Y. Zhang, H. Chen, J. Sun, L. He, A stochastic analysis of glass crack initiation under thermal loading, Appl. Therm. Eng, 67 (2014) 447-457.
[8] Y. Chang, S. Jung, S. Lee, J. Choi, Y. Kim, Fatigue data acquisition, evaluation and optimization of district heating pipes, Appl. Therm. Eng, 27 (2007) 2524-2535.
[9] D. Broek, Elementary engineering fracture mechanics, TheHague: Martinus Nijhoff Publishers, 1986.
[10] R. Ghfiri, H.J. Shi, R. Guo, G. Mesmacque, Effects of expanded and non-expanded hole on the delay of arresting crack propagation for aluminum alloys, Mater Sci Eng, (2000) 244-249.
[11] C. Shin, C. Wang, P. Song, Fatigue damage repair: a comparison of some possible methods, Int J Fatigue, 18 (1996) 535-546.
[12] N. Vulic´, S. Jecic´, V. GrubisĖ‡ic´, Validation of crack arrest technique by numerical modeling, Int J Fatigue, 19 (1997) 283-291.
[13] Z. Domazet, Comparison of fatigue crack retardation methods, Eng Failure Anal, 3 (1996) 137-147.
[14] E. Poursaeidi, H. Bazvandi, Effects of emergency and fired shut down on transient thermal fatigue life of a gas turbine casing, Applied Thermal Engineering, 100 (2016) 453-461.
[15] E.E. Gdoutos, Fracture Mechanics an Introduction, Springer, 2005.
[16] ABAQUS/Standard User’s Manual, in: V. 6.1 (Ed.) HKS Inc, 2000.
[17] Casting repair, Available from: www. (Accessed 01.03.2016).
[18] ZENCRACK User Manual, issue 6, Zentech Inc, 1999