000202599 001__ 202599
000202599 005__ 20240711092307.0
000202599 0247_ $$2Handle$$a2128/8988
000202599 0247_ $$2ISSN$$a1866-1793
000202599 037__ $$aFZJ-2015-04798
000202599 041__ $$aEnglish
000202599 1001_ $$0P:(DE-Juel1)145845$$aStille, Sebastian$$b0$$eCorresponding author$$gmale$$ufzj
000202599 245__ $$aVery High Cycle Fatigue Behavior of Riblet Structured High Strength Aluminium Alloy Thin Sheets$$f2015-01-31
000202599 260__ $$aJülich$$bForschungszentrum Jülich GmbH Zentralbibliothek, Verlag$$c2015
000202599 300__ $$aXII, 123 S.
000202599 3367_ $$0PUB:(DE-HGF)11$$2PUB:(DE-HGF)$$aDissertation / PhD Thesis$$bphd$$mphd$$s1437397648_27750
000202599 3367_ $$0PUB:(DE-HGF)3$$2PUB:(DE-HGF)$$aBook$$mbook
000202599 3367_ $$02$$2EndNote$$aThesis
000202599 3367_ $$2DRIVER$$adoctoralThesis
000202599 3367_ $$2BibTeX$$aPHDTHESIS
000202599 3367_ $$2DataCite$$aOutput Types/Dissertation
000202599 3367_ $$2ORCID$$aDISSERTATION
000202599 4900_ $$aSchriften des Forschungszentrums Jülich Reihe Energie & Umwelt / Energy & Environment$$v262
000202599 502__ $$aRWTH  Aachen, Diss., 2015$$bDr.$$cRWTH  Aachen$$d2015
000202599 520__ $$aFatigue testing was performed on two age hardened high strength aluminum alloys (AA 2024 T351 and AA 7075 T6) at ultrasonic frequencies of around 20 kHz in fully reversed axial loading (R = -1). Tests were carried out on flat and riblet structured thin sheets in order to evaluate their usability for a novel technique for aerodynamic drag reduction as well as for gaining further insight into the relevant degradation and failure mechanisms. The studied riblets were of semi-circular geometry and produced by a flat rolling process which was developed at the Institute of Metal Forming (RWTH Aachen University). Important aspects of the present work are the influence of commercially pure CP Al claddings – which are frequently used for the prevention of corrosion – as well as of different riblet dimensions on the fatigue performance. Whereas the bare material shows a continuous transition from high cycle fatigue(HCF) to very high cycle fatigue (VHCF), for clad sheets a sharp transition from HCF failure (up to some 10$^{6}$ cycles) to run-outs (at $\geq$ some 10$^{9}$ cycles) is observed. Particularly in the megacycle regime, the fatigue life of the structured bare materialis – compared to the non-structured case – significantly reduced by stress concentrations induced by the surface structure. However, the fatigue performance of clad material is not negatively affected by the riblets. In this case, the threshold value at which the transition from HCF failure to run-outs occurs was even higher than in the flat case. The transition stress differs with cladding thickness as well as with riblet geometry. Fatigue cracks are – even in the case of run-outs– always initiated at the surface of the clad layer and grow easily to the substrate. Specimens only fail, if the threshold for further crack growth into the substrate is exceeded. The fatigue limit of both, the flat and riblet structured clad material can thus be described by a fracture mechanics approach using a Kitagawa-Takahashi diagram. In the case of structured clad material, the threshold for fatigue failure is not only directly affected by the remaining thickness of the cladding below the riblet structure. Finite element (FEM) simulations demonstrate that due to plastic deformation a stress redistribution in the CP Al layer occurs which modifies the effective stress at the interface (cladding / substrate). The effective interface stress is thus as well a function of cladding thickness, which therefore, besides the direct effect, also indirectly influences the stress intensity of through-cladding cracks. Further FEM simulations demonstrate that riblets can be optimized with respect to VHCF performance, if the thickness of the clad layer below the riblet valleys is around25% of the riblet diameter. The failure mechanisms of both tested alloys are similar to each other. Further aspects covered in this work are a detailed analysis of material changes induced by the structuring process and the development of a bending testing setup in which the loading conditions resemble the exposure during use in active drag reduction systems.
000202599 536__ $$0G:(DE-HGF)POF3-111$$a111 - Efficient and Flexible Power Plants (POF3-111)$$cPOF3-111$$fPOF III$$x0
000202599 536__ $$0G:(DE-Juel1)HITEC-20170406$$aHITEC - Helmholtz Interdisciplinary Doctoral Training in Energy and Climate Research (HITEC) (HITEC-20170406)$$cHITEC-20170406$$x1
000202599 650_7 $$xDiss.
000202599 8564_ $$uhttps://juser.fz-juelich.de/record/202599/files/Energie_Umwelt_262.pdf$$yOpenAccess
000202599 8564_ $$uhttps://juser.fz-juelich.de/record/202599/files/Energie_Umwelt_262.gif?subformat=icon$$xicon$$yOpenAccess
000202599 8564_ $$uhttps://juser.fz-juelich.de/record/202599/files/Energie_Umwelt_262.jpg?subformat=icon-1440$$xicon-1440$$yOpenAccess
000202599 8564_ $$uhttps://juser.fz-juelich.de/record/202599/files/Energie_Umwelt_262.jpg?subformat=icon-180$$xicon-180$$yOpenAccess
000202599 8564_ $$uhttps://juser.fz-juelich.de/record/202599/files/Energie_Umwelt_262.jpg?subformat=icon-640$$xicon-640$$yOpenAccess
000202599 8564_ $$uhttps://juser.fz-juelich.de/record/202599/files/Energie_Umwelt_262.pdf?subformat=pdfa$$xpdfa$$yOpenAccess
000202599 909CO $$ooai:juser.fz-juelich.de:202599$$pdnbdelivery$$pVDB$$pdriver$$popen_access$$popenaire
000202599 915__ $$0StatID:(DE-HGF)0510$$2StatID$$aOpenAccess
000202599 9141_ $$y2015
000202599 9101_ $$0I:(DE-588b)5008462-8$$6P:(DE-Juel1)145845$$aForschungszentrum Jülich GmbH$$b0$$kFZJ
000202599 9131_ $$0G:(DE-HGF)POF3-111$$1G:(DE-HGF)POF3-110$$2G:(DE-HGF)POF3-100$$3G:(DE-HGF)POF3$$4G:(DE-HGF)POF$$aDE-HGF$$bEnergie$$lEnergieeffizienz, Materialien und Ressourcen$$vEfficient and Flexible Power Plants$$x0
000202599 920__ $$lyes
000202599 9201_ $$0I:(DE-Juel1)IEK-2-20101013$$kIEK-2$$lWerkstoffstruktur und -eigenschaften$$x0
000202599 9801_ $$aFullTexts
000202599 980__ $$aphd
000202599 980__ $$aVDB
000202599 980__ $$aFullTexts
000202599 980__ $$aUNRESTRICTED
000202599 980__ $$abook
000202599 980__ $$aI:(DE-Juel1)IEK-2-20101013
000202599 981__ $$aI:(DE-Juel1)IMD-1-20101013