Determination of fracture mechanics parameters structural components with surface crack under thermomechanical loads

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. 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 discs 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 axis-symmetric finite element models were created to simulate a disc and the portion of a blade. The finite element method (FEM) 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 a correct determination of SIF in this paper, combining J-integral approach and FEM is used. J-integral is a path independent integral around the crack tip.

Buckling and postbuckling behavior of shell type structures under thermo mechanical loads

“…The composite laminates due to their high specific strength and stiffness are increasingly used in weight-sensitive applications such as aircraft and space vehicles [1][2][3]. Most of these vehicles have to operate in hostile thermal environments; as a result, the structural components of these vehicles are subjected to thermal loads [4][5][6].…”

Numerical analysis of the support platform for an unmanned aerial vehicle

“…Such methods allow for an accurate, fast and inexpensive testing of various load patterns applied to aircraft components. The FEM fatigue life analysis of aircraft structural components was discussed in [8]. A fatigue analysis is fundamental because fatigue is one of the main factors behind service failures in aircraft components [9].…”

Residual life estimation of cracked aircraft structural components

“…Since 1970 USAF has developed the damage tolerance approach [1][2][3]. For the application of fracture mechanics principles to cracks emanating from holes or between two holes, knowledge of the stress intensity is a prerequisite [4][5][6]. Fatigue life prediction concepts can be differentiated by the failure criterion applied, i.e.…”