Corrosion effect, constraint and path orientation estimated in cracked gas turbine blade

• Published in: Engineering failure analysis 2020-03, Vol.110, p.104345, Article 104345
• Main Authors: Mouna, Amara, Boukortt, Hocine, Hadj Meliani, Mohammed, Muthanna, Bassam G.N., Suleiman, Rami K., Sorour, Ahmad A., Pluvinage, Guy, Azari, Zitouni
• Format: Article
• Language: English
• Subjects: Blade; FEA; Gas turbine; MATS; Physics; T-stress
• ISSN: 1350-6307; 1873-1961; 1350-6307
• DOI: 10.1016/j.engfailanal.2019.104345

•Incremental method is used in a search of the crack propagation angle.•Crack path is associated with local fracture criterion including the constraint parameter (T-stress).•The MATS criterion for the mixed mode I/II and I/III loading, was employed for predicting the angle of surface crack for gas turbine blade.•The constraint in the MFMC describe the influence of the specimen type on the transition stress intensity factor.•The constraint is given by the linear relation between the transition stress intensity factor in ceramic.•The transferability is confirmed between different types of specimen, loading mode, notch acuity, and thickness. The severe damage of gas turbine is due to the failure of the blade, in which the occurrence of a serious pitting occurred on the blade surfaces was evidence of fatigue marks in the fracture surface. This paper deals with the effect of semi-elliptical crack propagation on the crack path using a basic approach in predicting crack paths, namely, incremental methods. The crack position was chosen at the node coordinate where we have the maximum principal stresses. In this node, we have created a semi-elliptical crack and we have compared the results with the Stress Intensity Factors and T-stress values. The local fracture criterion of the maximum average tangential stress in the vicinity of fracture process zone including two terms of the Williams series solution for the mixed mode I/II loading has been used for predicting the angle of surface crack growth. The volumetric method (VM) for the compression-sensitive materials is described by a linear combination of the effective stress and the effective stress intensity factor. The results of our finite element computations based on a two-parameter fracture mechanics formulation showed that the T-stress has significant effects on the crack path.