Author(s):
1. Katarina Maksimović, Serbia
2. Dragi Stamenković, Termoelektro Belgrade, Serbia
3. Slobodanka Boljanović, High School of Mechanical Engineering, Belgrade, Serbia
4. Mirko Maksimović, Waterworks and Sewerage, Serbia
5. Ivana Vasović, Institut Goša, Milana Rakića 35, Beograd, Serbia

Abstract:
In this work, the computation procedure is performed to determine stress intensity factors for structures with surface crack under the influence of thermal loads. Structural components of aero engine turbine are the most important components. It operate 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 constant load. If the crack grows long enough, sudden failure can occur with catastrophic consequences. 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 axi-symmetric finite element models were created to simulate a disc and the portion of a 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 path independent integral around the crack tip. The stress intensity factor (SIF) for an embedded elliptical crack in a turbine rotor under thermal and centrifugal loading, for a semi-elliptical surface crack in a finite plate are determined by means of finite elements and J-integral method.

Key words:
Aero-engine, Turbine components, Fracture mechanics, Stress intensity factor, J-Integral approach

Thematic field:
Mechanics and Design

Date of abstract submission:
26.02.2017.

Conference:
13th International Conference on Accomplishments in Mechanical and Industrial Engineering