PSI - Issue 13

ScienceDirect Available online at www.sciencedirect.com Av ilable o line at ww.sciencedire t.com ScienceDirect Structural Integrity Procedia 00 (2016) 000 – 000 Procedia Structural Integrity 13 8 57–62 Available online at www.sciencedirect.com Structural Integrity Procedia 0 (2018) 0– 0 Available online at www.sciencedirect.com Structural Integrity Procedia 00 (2018) 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. © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. ECF22 - Loading and Environmental e ff ects on Structural Integrity Biaxial experiments on the e ff ect of non-proportional loading paths on damage and fracture behavior of ductile metals Moritz Zistl a, ∗ , Ste ff en Gerke a , Michael Bru¨nig a a Institut fu¨r Mechanik und Statik, Universita¨ t der Bundeswehr Mu¨nchen, Werner-Heisenberg-Weg 39, 85579 Neubiberg, Germany Abstract The paper deals with a series of new experiments to study the e ff ect of non-proportional loading paths on damage and fracture behavior of ductile metals. In this context, a thermodynamically consistent anisotropic continuum damage model is presented. It takes into account the e ff ect of stress state on damage conditions as well as on the evolution of damage strains. Di ff erent branches of the damage criteria corresponding to various ductile damage and fracture mechanisms depending on stress state are considered. The two-dimensionally loaded X0-specimen covering a wide range of stress triaxialities and Lode parameters in the tension and shear stress domains is being used. These tests are driven under di ff erent non-proportional loading paths. The formation of strain fields of the specimens is recorded by digital image correlation technique. Furthermore, scanning electron microscope analysis of the fracture surfaces clearly shows various failure modes corresponding to these loading conditions. c 2018 The Authors. Publishe by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. Keywords: Damage d fracture; biaxial experiments; non-proportional loading paths; digital image correlation; s anning electron microscopy 1. Introduction Accurate and realistic mo eling of the deformation and fracture behavior of ductile sheet metals is of interest in several engineering disciplines. With increasing inelastic deformations damage and fracture mechanisms occur in the material. It can be noted that they depend on the stress state (Bao and Wierzbicki (2004); Gao et al. (2010)). Under tension dominated stress conditions damage in ductile metals is mainly caused by nucleation, growth and coalescence of voids whereas the formation of micro-shear-cracks is the predominant damage mechanism under shear and compression dominated stress states. In addition, the damage behavior depends as well strongly on the loading path of the material sample. Therefore, this path dependency has to be studied experimentally. In the present paper, a continuum damage model using functions for di ff erent damage modes will be presented and detailed results of biaxial experiments presented and discussed. Biaxial experiments with the recently developed cruciform X0-specimen will be shown with focus on the e ff ect of non-proportional loading paths. Digital image correlation technique is used ECF22 - Loading and Environmental e ff ects on Structural Integrity Biaxial experiments on the e ff ect of non-proportional loading paths on damage a d fracture behavior of ductile metals Moritz Zistl a, ∗ , Ste ff en Gerke a , Michael Bru¨nig a a Institut fu¨r Mechanik und Statik, Universita¨ t der Bundeswehr Mu¨nchen, Werner-Heisenberg-Weg 39, 85579 Neubiberg, Germany Abstract The paper deals with a series of new experiments to study the e ff ect of non-proportional loading paths on damage and fracture behavior of ductile metals. In this context, a thermodynamically consistent anisotropic continuum damage model is presented. It takes into account the e ff ect of stress state on damage conditions as well as on the evolution of damage strains. Di ff erent branches of the damage criteria corresponding to various ductile damage and fr cture mechanisms depending on stress state are considered. The two-dimensionally l aded X0-specimen covering a wide range of stress triaxi lities and Lode parameters in the tension and shear stress domains is being used. These tests are driven under di ff erent non-proportional loading paths. The formation of strain fields of the specimens is recorded by digital image correlation technique. Furthermore, scanning electron microscope analysis of the fracture surfaces clearly shows various failure modes corresponding to these loading conditions. c 2018 The Authors. Published by Elsevier B.V. P r-review unde responsibility of the ECF22 organizers. Keywords: Damage and fracture; biaxial experiments; non-proportional loading paths; digital image correlation; scanning electron microscopy 1. Introduction Accurate and realistic modeling of the deformation and fracture behavior of ductile sheet metals is of interest in several engineering disciplines. With increasing inelastic deformations damage and fracture mechanisms occur in the material. It can be noted that they depend on the stress state (Bao and Wierzbicki (2004); Gao et al. (2010)). Under tension dominated stress conditions damage in ductile metals is mai ly caused by nucleation, growth and coalescence of voids whereas the formation of micro-shear-cracks is the predominant damage mechanism under shear and compression dominated stress states. In addition, the damage behavior depends as well strongly on the loading path of the material sample. Therefore, this path dependency has to be studied experimentally. In the present paper, a continuum damage model using functions for di ff erent damage modes will be presented and detailed results of biaxial experiments presented and discussed. Biaxial experiments with the recently developed cruciform X0-specimen will be shown with focus on the e ff ect of non-proportional loading paths. Digital image correlation technique is used © 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.

2452-3216 © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of PCF 2016. ∗ Corresponding author. Tel.: + 49-89-6004-3413 ; fax: + 49-89-6004-4549. E-mail address: moritz.zistl@unibw.de 2210-7843 c 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. ∗ Corresponding author. Tel.: + 49-89-6004-3413 ; fax: + 49-89-6004-4549. E-mail address: moritz.zistl@unibw.de 2210-7843 c 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. * Corresponding author. Tel.: +351 218419991. E-mail address: amd@tecnico.ulisboa.pt 2452-3216  2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. 10.1016/j.prostr.2018.12.010