improving the transient thermal fatigue life of a gas turbine casing by drilling stop holes and inserting pins into them

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.