Calibrated the direct current potential drop method for fatigue crack propagation testing of nickel-based superalloy with film cooling hole

Xi Ren, Fei Li, Zhixun Wen, Hao Cheng, Zhufeng Yue

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

Turbine blades in aviation engines commonly feature a nickel-based superalloy structure integrated with film cooling holes to enhance inlet gas temperature. However, the presence of these film cooling holes often results in frequent occurrences of fracture failures nearby. The direct current potential drop (DCPD) method, renowned for its exceptional crack sensitivity, is frequently utilized for crack length monitoring. This study establishes a FEM model of the film cooling hole plate specimen to determine the optimal probe point location. Subsequently, a mapping relationship is derived to calibrate Johnson's formula, accounting for the unequal crack lengths at the edges of film cooling holes. It is confirmed that the crack length measured by the DCPD method represents the cumulative crack lengths on both sides of the hole. Fatigue crack propagation experiments are then conducted, with crack length monitored using a microscope. The results affirm the successful application of the calibrated formula to the film cooling hole plate specimen, exhibiting an average error within 0.1 mm.

Original languageEnglish
Article number104706
JournalTheoretical and Applied Fracture Mechanics
Volume134
DOIs
StatePublished - Dec 2024

Keywords

  • Crack monitoring
  • Direct current potential drop method
  • Film cooling hole
  • Thermal-electric coupling model

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