PSI - Issue 2_A

ScienceDirect Available online at www.sciencedirect.com Av ilable o line at ww.sciencedire t.com cienceDirect Structural Integrity Procedia 00 (2016) 000 – 000 Procedia Struc ural Integrity 2 (2016) 3109–3116 Available online at www.sciencedirect.com Structural Integrity Procedia 00 (2016) 000–000 Available online at www.sciencedirect.com Structural Integrity Procedia 00 (2016) 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. 21st European Conference on Fracture, ECF21, 20-24 June 2016, Catania, Italy Biaxial Experiments and Numerical Simulations on Damage and Fracture Mechanisms in Ductile Metals at Di ff erent Loading Conditions Michael Bru¨nig a, ∗ , Ste ff en Gerke a , Marco Schmidt a a Institut fu¨r Mechanik und Statik, Universita¨ t der Bundeswehr Mu¨nchen, Werner-Heisenberg-Weg 39, 85577 Neubiberg, Germany Abstract The paper deals wi h an anisotrop damag a d frac re model for ductile m tals. Th phenomenologi al pproach takes into account the e ff ect of stress state on damage condition and damage strain evolution laws. Di ff erent branches of these criteria are considered corresponding to di ff erent damage and fracture mechanisms depending on stress triaxiality and the Lode parameter. To validate these criteria new experiments with two-dimensionally loaded specimens are presented. Specimen’s geometry and loading conditions as well as their influence on stress states are discussed in detail. They allow combined shear-tension and shear compression stress states. Digital image correlation technique has been used to analyze current strain fields in critical regions of the specimens. Corresponding numerical simulations of the experiments show that they cover a wide range of stress states. c 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ECF21. Keywords: Exp iments; Digital image correlation technique; Numerical simulations; Str ss state dependence; Ductil damag nd fracture 1. Introduction During the last decades the demand for and the use of high quality metals like high strength steels, advanced high strength steels and aluminum alloys has been remarkably increased. For example, there are requirements on lightweight design leading to improved energy consumption or cost e ffi ciency and, at the same time, to enforce the safety demands. Therefore, material properties have to be enhanced to avoid early localization of inelastic strains as well as damage and fracture of structural components undergoing complex loading conditions. In this context, advanced constitutive models are needed to simulate the material behavior under di ff erent loading processes. Based on intensive experimental and numerical investigations it is now well known that the characteristics of damage and fracture mechanisms depend on stress state acting in a material point. For example, under tension loading conditions with high positive stress triaxialities damage in ductile metals is mainly caused by nucleation, growth and coalescence of micro-voids. On the other hand, under shear and compression loading conditions with nearly zero or negative stress triaxiality the predominant damage mechanisms are formation, growth and coalescence of micro- 21st European Conference on Fracture, ECF21, 20-24 June 2016, Catania, Italy Biaxial Experiments and Numerical Simulations on Damage and Fracture Mechanisms in Ductile Metals at Di ff erent Loading Conditions Michael Bru¨nig a, ∗ , Ste ff en Gerke a , Marco Schmidt a a Institut fu¨r Mechanik und Statik, Unive sita¨ t der Bundeswehr Mu¨nch n, W rner-Heisenberg-Weg 39, 85577 Neubiberg, Germany Abstract The paper deals with an anisotropic damage and fracture model for ductile metals. The phenomenological approach takes into account the e ff ect of stress state on damage condition and damage strain evolution laws. Di ff erent branches of these criteria are considered corresponding to di ff erent damage and fracture mechanisms depending on stress triaxiality and the Lode parameter. To validate these criteria new experiments with two-dimensionally loaded specimens are presented. Specimen’s geometry and loading conditions as well as their influence on stress states are discussed in detail. They allow combined shear-tension and shear compression stress states. Digital image correlation technique has been used to analyze current strain fields in critical regions of the specimens. Corresponding numerical simulations of the experiments show that they cover a wide range of stress states. c 2016 The Authors. Published by Elsevier B.V. Pe r-r v ew under res on ibility of the Scientific Committee of ECF21. Keywords: Experiments; Digital image correlation technique; Numerical simulations; Stress state dependence; Ductile damage and fracture 1. Introduction During the last decades the demand for and the use of high quality metals like high strength steels, advanced high strength steels and aluminum alloys has been remarkably increased. For example, there are requirements on lightweight design leadi g to improved energy c nsumption or cost e ffi ciency and, at the same time, to enforce the safety demands. Therefore, material properties have to be enhanced to avoid early localization of inelastic strains as well as damage and fracture of structural components undergoing complex loading conditions. In this context, advanced constitutive models are needed to simulate the material behavior under di ff erent loading processes. Based on intensive experimental and numerical investigations it is now well known that the characteristics of damage and fracture mechanis s depend on stress state acting in a material point. For example, under tension loading conditions with high positive stress triaxialities damage in ductile etals is mainly caused by nucleation, growth and coalescence of micro-voids. On the other hand, under shear and compression loading conditions with nearly zero or negative stress triaxiality the predominant damage mechanisms are formation, growth and coalescence of micro- Copyright © 2016 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). er-review under responsibility of the S ientific Committee of ECF21. © 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.: +351 218419991. E-mail address: amd@tecnico.ulisboa.pt

2452-3216 © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of PCF 2016. Copyright © 2016 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license ( http://creativecommons.org/licenses/by-nc-nd/4.0/ ). Peer review under responsibility of the Scientific Committee of ECF21. 10.1016/j.prostr.2016.06.388 ∗ Corresponding author. Tel.: + 49-89-60043415 ; fax: + 49-89-60044549. E-mail address: michael.bruenig@unibw.de 2452-3216 c 2016 The Auth rs. Publi hed by Elsevier B.V. Pe r-review under responsibility of the Scientific Committee of ECF21. ∗ Corresponding author. Tel.: + 49-89-60043415 ; fax: + 49-89-60044549. E-mail address: michael.bruenig@unibw.de 2452-3216 c 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ECF21.