Evaluation of several multiaxial high cycle fatigue endurance criteria

Download
index.pdf
2018
Engin, Zafer
Show full item record
287
views
174
downloads
Multiaxial high cycle fatigue is an important failure mode for industrial applications as it is experienced by many engineering parts such as rotor blades and crankshafts. Determining the critical locations and especially the fatigue lives of such components have great importance. Therefore, a methodology is needed which would replace expensive and time-consuming test campaigns as it is not possible and feasible to simulate all the loading scenarios that component would experience during the service life. The purpose of this thesis is to evaluate the state-of-the-art multiaxial endurance criteria available in the literature, with respect to their capability of handling multiaxial load interactions, phase difference, mean stress, and calculation speed. The criteria transform the multiaxial stress state to a damage parameter which is compared with endurance limit to determine whether the structure endures the loading or not. In this thesis, criteria from the literature belonging to equivalent stress, invariant based and critical plane are considered. Extensive experimental data is obtained from literature to compare the estimations of the criteria and a MATLAB code is written for calculations. Life estimations are obtained for each experimental data and statistical analysis is performed for obtaining the general behavior of the criteria. Comparing each type of criteria we conclude that the equivalent stress methods give highly scattered estimations while invariant based methods yield vi more reliable results; however, best estimations are obtained by critical plane methods. For practical applications GAM (invariant based) or Papuga PCR (critical plane) may be implemented, former being fast and latter being more precise.
Material, Multiaxial fatigue., Metals
http://etd.lib.metu.edu.tr/upload/12622760/index.pdf
https://hdl.handle.net/11511/27530
Graduate School of Natural and Applied Sciences, Thesis

Suggestions

Characterization of Duplex Stainless Steel Weld Metals Obtained by Hybrid Plasma-Gas Metal Arc Welding
Yurtışık, Koray; Tirkeş, Süha; Gür, Cemil Hakan; Gürbüz, Rıza (FapUNIFESP (SciELO), 2013-07-01)
Despite its high efficiency, autogenous keyhole welding is not well-accepted for duplex stainless steels because it causes excessive ferrite in as-welded duplex microstructure, which leads to a degradation in toughness and corrosion properties of the material. Combining the deep penetration characteristics of plasma arc welding in keyhole mode and metal deposition capability of gas metal arc welding, hybrid plasma - gas metal arc welding process has considered for providing a proper duplex microstructure wi...
Utilization of friction stir processing to improve the mechanical properties of gas metal arc welded 5083 aluminum alloy plates
Takht Firouzeh, Shahin; Gür, Cemil Hakan; Department of Metallurgical and Materials Engineering (2016)
Fatigue failure of the welded structures is a major problem in engineering applications. It is known that the heat affected zone (HAZ) of the welded Al-alloys is prone to fail due to coarse microstructure and poor mechanical properties. Therefore, any improvement in HAZ may extend the service life of the welded component. The hypothesis of this study is that localized application of friction stir processing (FSP) before welding may improve the mechanical properties of HAZ, and thus, may reduce the fatigue c...
Investigating the effects of hardening of aluminium alloys on equal-channel angular pressing-A finite-element study
Karpuz, P.; Simsir, C.; Gür, Cemil Hakan (Elsevier BV, 2009-03-15)
Equal-channel angular pressing (ECAP) is a promising severe plastic deformation method for production of ultrafine-grained bulk metals and alloys with considerably improved mechanical properties. In this study, numerical experiments were carried out to investigate the effect of strain hardening of aluminum alloys on the process performance of ECAP via finite element modeling. In the constitutive model, isothermal-plane strain, frictionless condition was assumed. The numerical results showed that strain hard...
Validation of MISES 2 D Boundary Layer Code for High Pressure Turbine Aerodynamic Design
ANDREW, PHILIP; Kahveci, Harika Senem (2007-01-01)
Avoiding aerodynamic separation and excessive shock losses in gas turbine turbomachinery components can reduce fuel usage, and thus reduce operating cost. In order to achieve this, blading designs should be made robust to a wide range of operating conditions. Consequently, a design tool is needed which can be executed quickly for each of many operating conditions, and on each of several design sections which will accurately capture loss, turning and loading. This paper presents the validation of a boundary ...
DEVELOPMENT OF BOLTED FLANGE DESIGN TOOL BASED ON FINITE ELEMENT ANALYSIS AND ARTIFICIAL NEURAL NETWORK
Yildirim, Alper; Kayran, Altan; Gulasik, Hasan; Çöker, Demirkan; Gürses, Ercan (2015-11-19)
In bolted flange connections, commonly utilized in aircraft engine designs, structural integrity and minimization of the weight are achieved by the optimum combination of the design parameters utilizing the outcome of Many structural analyses. Bolt size, the number of bolts, bolt locations, casing thickness, flange thickness, bolt preload, and axial external force are some of the critical design parameters in bolted flange connections. Theoretical analysis and finite element analysis (FEA) are two main appr...
Citation Formats
Z. Engin, “Evaluation of several multiaxial high cycle fatigue endurance criteria,” M.S. - Master of Science, Middle East Technical University, 2018.
METU IIS - Integrated Information Service open@metu.edu.tr