Study of Mixed-Mode Cracking of Dovetail Root of an Aero-Engine Blade Like Structure

Giacomo Canale,Angelo Maligno,Prabhakar Sathujoda,Roberto Citarella,Moustafa Kinawy

doi:10.3390/app9183825

Giacomo Canale, Angelo Maligno + Show 3 more

Open Access

https://doi.org/10.3390/app9183825

Copy DOI

Abstract

Aerospace structures must be designed in such a way so as to be able to withstand even more flight cycles and/or increased loads. Damage tolerance analysis could be exploited more and more to study, understand, and calculate the residual life of a component when a crack occurs in service. In this paper, the authors are presenting the results of a systematic crack propagation analysis campaign performed on a compressor-blade-like structure. The point of novelty is that different blade design parameters are varied and explored in order to investigate how the crack propagation rate in low cycle fatigue (LCF, at R ratio R = 0) could be reduced. The design parameters/variables studied in this work are: (1) The length of the contact surfaces between the dovetail root and the disc and (2) their inclination angle (denoted as “flank angle” in the aero-engine industry). Effects of the friction coefficient between the disc and the blade root have also been investigated. The LCF crack propagation analyses have been performed by recalculating the stress field as a function of the crack propagation by using the FRacture ANalysis Code (Franc3D®).

Highlights

Fans, compressors, and turbine blades of aero-engines are highly stressed components, especially in the contact area between the blade root and the disc slot [1]
Compressors, and turbine blades of aero-engines are highly stressed components, especially in the contact area between the blade root and the disc slot [1]. This is due both to the high rotational speed of the shaft and to the aerodynamic load. Cracks may appear both in low cycle fatigue (LCF, defined in the aero-engine industry as the fatigue caused by the application and release of the main centrifugal and aerodynamic load, with stress ratio R = 0) and high cycle fatigue (HCF, defined in the aero-engine industry as the fatigue induced by the vibration loads)
Crack propagation has already been studied in fan, compressor, or turbine blades [1,2,3,4,5,6,7]

Summary

Introduction

Compressors, and turbine blades of aero-engines are highly stressed components, especially in the contact area between the blade root and the disc slot [1] This is due both to the high rotational speed of the shaft and to the aerodynamic load. A powerful and simple tool for crack propagation analyses has been released and used in several academic and industrial works: Franc3D [8,9]. It is a state-of-the-art 3D crack propagation tool developed by Cornell University

Objectives

Discussion

Conclusion