REPUBLIC OF SERBIA

MINISTRY OF DEFENCE

www.mod.gov.rs

MINISTRY OF DEFENCE

Material Resources Sector

Defensive Technologies Department

Military Technical Institute

www.vti.mod.gov.rs

DETERMINATION OF FRACTURE MECHANICS PARAMETERS IN AERO-ENGINE TURBINE COMPONENTS USING FEM AND J-INTEGRAL APPROACH

DRAGI STAMENKOVIĆ

Termoelektro, Belgrade, Serbia, e-mail: dragi33@gmail.com

KATARINA MAKSIMOVIĆ

City Administration of City of Belgrade, Belgrade, Serbia, katarina.maksimovic@beograd.gov.rs

Abstract: Rotational components of aero engine turbine are the most important components. It operates at high temperature and under conditions of extreme environmental attack such as oxidation, corrosion and wear. During the service of turbine, components suffer from initiation and increasing tip cracks. These conditions can cause cracking of rotational components. The failure damage modes of turbine are classified in terms of main components as flow path parts, rotating such as rotor, groove, disk, and blade. Aero-engine turbine components such as disks and blades are susceptible to environmentally assisted cracking. Unlike fatigue crack growth, this involves crack growth under thermal load. If the crack grows long enough, sudden failure can occur with catastrophic consequences. Therefore, it is (therefore) desirable to identify the limiting crack size within fixings so that they can be inspected at regular intervals and removed from service before failure occurs. Three dimensional finite element models were created to simulate a portion of a turbine blade. The finite element method allowed the prediction of the point of crack initiation and the crack propagation using the orientations of the maximum principal stresses. Stress intensity factor (SIF) is the base parameter in strength analysis regarding fracture mechanics. For correct determination SIF in this paper, combining J-integral approach and FEM is used. J-integral is independent path integral around the crack tip.

Key words: Aero-engine, Turbine components, Cracks, Stress intensity factor, J-Integral