PSI - Issue 7

ScienceDirect Available online at www.sciencedirect.com Av ilable o line at ww.sciencedire t.com S ienceDirect Structural Integrity Procedia 00 (2016) 000 – 000 Procedia Structu al Integrity 7 (2017) 407–414 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2017) 000–000 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2017) 000–000

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XV Portuguese Conference on Fracture, PCF 2016, 10-12 February 2016, Paço de Arcos, Portugal Thermo-mechanical modeling of a high pressure turbine blade of an airplane gas turbine engine P. Brandão a , V. Infante b , A.M. Deus c * a Department of Mechanical Engineering, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1, 1049-001 Lisboa, Portugal b IDMEC, Department of Mechanical Engineering, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1, 1049-001 Lisboa, Portugal c CeFEMA, Department of Mechanical Engineering, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1, 1049-001 Lisboa, Portugal Abstract During their operation, modern aircraft engine components are subjected to increasingly demanding operating conditions, especially the high pressure turbine (HPT) blades. Such conditions cause these parts to undergo different types of time-dependent degradation, one of which is creep. A model using the finite element method (FEM) was developed, in order to be able to predict the creep behaviour of HPT blades. Flight data records (FDR) for a specific aircraft, provided by a commercial aviation company, were used to obtain thermal and mechanical data for three different flight cycles. In order to create the 3D model needed for the FEM analysis, a HPT blade scrap was scanned, and its chemical composition and material properties were obtained. The data that was gathered was fed into the FEM model and different simulations were run, first with a simplified 3D rectangular block shape, in order to better establish the model, and then with the real 3D mesh obtained from the blade scrap. The overall expected behaviour in terms of displacement was observed, in particular at the trailing edge of the blade. Therefore such a model can be useful in the goal of predicting turbine blade life, given a set of FDR data. Copyright © 2017 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of the 3rd International Symposium on Fatigue Design and Material Defects. 3rd International Symposium on Fatigue Design and Material Defects, FDMD 2017, 19-22 September 2017, Lecco, Italy Fatigue strength and life determination of weldments based on fracture mechanics U. Zerbst a *, M. Madia a and H.Th. Beier b a Bundesanstalt für Materialforschung und -prüfung (BAM), 9.1, Unter den Eichen 87, D-12205 Berlin, Germany b Technische Universität Darmstadt, Materials Mechanics Group, Franziska-Braun-Str. 3, D-64287 Darmstadt, Germany Abstract The paper provides an overview on the results of a German cluster project on the use of fracture mechanics to the determination of the fatigue strength of weldments with fatigue cracks originating at the weld toes. The approach includes (a) a concept for short crack propagation for which the common ∆ K concept is not applicable and the crack closure effects are still being gradually build up, (b) a method for determining fatigue life relevant initial crack sizes as they are needed in any fracture mechanics analysis and (c) multiple c acking and crack co lescenc at load levels higher than th endurance l mit. The alyses are stochastically performed. Both, the endurance limit and the finite life branch of the S-N curve are determined. Besides a brief introduction into the approach, validation examples are presented. These comprise different weld ent types (butt welds, cross joints and longitud al stiffened plates), two steels (S355NL and S960QL) of quite different strengths, different weld geometries due to different welding techniques (WIG, MAG), as-wel ed and stress relieved weld and different st ess ratios varying from R = -1 to R = 0.5. Keywo ds: Weldm nts; fatigue strength, fracture mechanics; initial crack size; short cra k p opagation; multiple crack propagation Introduction The idea to apply fracture mechanics to the fatigue strength and life of weldments is anything but new. Almost half a century ago Maddox (1970) was one of the first to mention it. In 1974 he wrote: “It is now widely recognized that flaws will inevitably exist in welded structures and the old idea of removing all detectable defects must be replaced by the 'fitness for purpose' design philosophy. This makes it necessary to define reliable methods of assessing the significance of flaws, particularly in the context of fatigue, …. 3rd International Symposium on Fatigue Design and Material Defects, FDMD 2017, 19-22 September 2017, Lecco, Italy Fatigue stre gth and life determination of weldments based on fracture mechanics U. Zerbst a *, M. Madia a and H.Th. Beier b a Bundesanstalt für Materialforschung und -prüfung (BAM), 9.1, Unter den Eichen 87, D-12205 Berlin, Germany b Technische Universität Darmstadt, Materials Mechanics Group, Franziska-Braun-Str. 3, D-64287 Darmstadt, Germany Abstract The paper provides an overview on the results of a German cluster project on the use of fracture mechanics to the determination of the fatigue strength of weldments with fatigue cracks originating at the weld toes. The approach includes (a) a concept for short crack propagation for which the common ∆ K c ncept is not applicable and the crack closure effects are still being gradually build up, (b) a method for determining fatigue life r levant initial crack sizes as they are needed in any fractur mechanics analysis and (c) multiple cracking and crack coalescence at load levels higher than the endurance limit. The analyses are stochastically performed. Both, the endurance limit and the finite life branch of the S-N curve are determined. Besides a brief introduction into the pproa h, valid tion examples are presented. These co prise different weldment types (butt welds, cross j ints and longitudinal stiffened plates), two steels (S355NL and S960QL) of quite different strengths, different weld geometries due to different welding techniques (WIG, MAG), as-welded and stress relieved welds and different stress ratios varying from R = -1 to R = 0.5. Keywords: Weldments; fatigue strength, fracture mechanics; initial crack size; short crack propagation; multiple crack propagation Introduction The idea to apply fracture mechanics to the fatigue strength and life of weldments is anything but new. Almost half a century ago Maddox (1970) was one of the first to mention it. In 1974 he wrote: “It is now widely recognized that flaws will inevitably exist in weld d structures and the ld dea of removing all detectable d fects must be replaced by the 'fitness for purpose' design philosophy. This makes it necessary to define reliable methods of assessing the significance of flaws, particularly in the context of fatigue, …. © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of PCF 2016. Keywords: High Pressure Turbine Blade; Creep; Finite Element Method; 3D Model; Simulation.

* Corresponding author. Tel.: +49 (0) 30 8104 1531; fax: +49 (0) 30 8104 1537. E-mail address: uwe.zerbst@bam.de * Corresponding author. Tel.: +49 (0) 30 8104 1531; fax: +49 (0) 30 8104 1537. E-mail address: uwe.zerbst@bam.de

* Corresponding author. Tel.: +351 218419991. E-mail address: amd@tecnico.ulisboa.pt 2452-3216 © 2017 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of the 3rd International Symposium on Fatigue Design and Material Defects. 2452-3216 © 2017 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of the 3rd International Symposium on Fatigue Design and Material Defects.

2452-3216 © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of PCF 2016.

2452-3216 Copyright  2017 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of the 3rd International Symposium on Fatigue Design and Material Defects. 10.1016/j.prostr.2017.11.106