PSI - Issue 2_B

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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 Notch Support for LCF-Loading: A Fracture Mechanics Approach C. Kontermann a, ∗ , H. Almstedt b , A. Scholz a , M. Oechsner a a Institut fuer Werksto ff kunde, Grafenstrasse 2, 64283 Darmstadt, Germany b Siemens AG, Rheinstrasse 100, 45478 Muelheim a. d. Ruhr, Germany Abstract The demand for an increase in flexible operation of power plants provides a key challenge. Solutions for new components as well as for units in operation have to be developed to safely all w for more load cycles and faster start-up times. One way to realize this is to improve the lifetime assessme t methods by reducing implied conservatisms. The presented work focuses on the description of notch support e ff ects at elevated temperatures for the LCF-regime. At first, a tailored experimental set-up using notched round-bars is introduced. Those tests are performed under global strain control and are equipped with an Alternating Current Potential Drop (ACPD) measurement system. The experimental results show that the crack growth phase up to a so called ”technical crack size” is of major relevance to describe notch support e ff ects. That is why within the second part of this paper, a concept is introduced to consider this early crack growth phase within a lifetime assessment approach. Within this concept, fracture mechanical parameters are determined by applying a novel energy-based Finite Element approach. Suggestions are presented to define proper values of the cyclic J -Integral as well as of the amount of Plasticity Induced Crack Closure (PICC). Finally, the concept is applied and validated by comparing the simulation approach with the experimental results. c 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ECF21. Keywords: Notch Support; FEM-based Fracture Mechanics; Cyclic J -Integral; PICC Notches are by design inevitable in most engineering structures and the resulting stress-raisers are a typical source for fatigue issues. Improving lifetime prediction methods for such locations are of great interest to avoid unplanned component failure as well as unnecessarily short inspection intervals. The type of loading acting on structures can vary from High-Cycle-Fatigue (HCF), dominated by elastic stresses and a large number of cycles > 10 7 , to Low Cycle-Fatigue (LCF), with high elastic-plastic stresses and cycles to crack initiation in the range of 10,000. The focus of the work presented in this paper is related to LCF from thermal-stress induced loading. The local concept is typically applied in many engineering methods, i.e. an equivalent stress or strain is determined locally at a component notch-root and compared with test data derived from smooth specimen. To obtain the LCF test data, strain controlled experiments with standardized smooth specimens are carried out until crack initiation. Here, 21st European Conference on Fracture, ECF21, 20-24 June 2016, Catania, Italy otch upport for - oading: racture echanics pproach C. onter ann a, ∗ , . l stedt b , . Scholz a , . echsner a a Institut fuer Werksto ff kunde, Grafenstrasse 2, 64283 Darmstadt, Germany b Siemens AG, Rheinstrasse 100, 45478 Muelheim a. d. Ruhr, Germany Abstract The demand for an increase in flexible operation of power plants provides a key challenge. Solutions for new components as well as for units in operation have to be developed to safely allow for more load cycles and faster start-up times. One way to realize this is to improve the lifetime assessment methods by reducing implied conservatisms. The presented work focuses on the description of notch support e ff ects at elevated temperatures for the LCF-regime. At first, a tailored experimental set-up using notch d round-bars is introduced. Those tests are performed under global strain control and are equipped with an Alternat ng Current Potential Drop (ACPD) measurement system. The experiment l results show that the crack growth phase up to a so called ”technical crack size” is of major relevance to describe notch support e ff ects. That is why within the second part of this paper, a concept is introduced to consider this early crack growth phase within a lifetime assessment approach. Within this concept, fracture mechanical parameters are determined by applying a novel energy-based Finite Element approach. Suggestions are presented to define proper values of the cyclic J -Integral as well as of the amount of Plasticity Induced Crack Closure (PICC). Finally, the concept is applied and validated by comparing the simulation approach with the experimental results. c 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ECF21. Keywords: Notch Support; FEM-based Fracture Mechanics; Cyclic J -Integral; PICC 1. Introduction Notches are by design inevitable in most engineering structures and the resulting stress-raisers are a typical source for fatigue issues. Improving lifetime prediction methods for such locations are of great interest to avoid unplanned component failure as well as unnecessarily short inspection intervals. The type of loading acting on structures can vary from High-Cycle-Fatigue (HCF), dominated by elastic stresses and a large number of cycles > 10 7 , to Low Cycle-Fatigue (LCF), with high elastic-plastic stresses and cycles to crack initiation in the range of 10,000. The focus of the work presented in this paper is related to LCF from thermal-stress induced loading. The local concept is typically applied in many engineering methods, i.e. an equivalent stress or strain is determined locally at a component notch-root and compared with test data derived from smooth specimen. To obtain the LCF test data, strain controlled experiments with standardized smooth specimens are carried out until crack initiation. Here, Copyright © 2016 The Aut ors. Published by Elsevier B.V. This s an op n access article under the CC BY-NC-ND licens (ht p:// ativecommons.org/licenses/by-nc-nd/4.0/). r vie under esponsibility of the Scientific 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. 1. Introduction

* 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.2016.06.390 ∗ Corresponding author. Tel.: + 49-6151-16-25316 ; fax: + 49-6151-16-25122. E-mail address: kontermann@mpa-ifw.tu-darmstadt.de 2452-3216 c 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ECF21. ∗ Corresponding author. Tel.: + 49-6151-16-25316 ; fax: + 49-6151-16-25122. E-mail address: kontermann@mpa-ifw.tu-darmstadt.de 2452-3216 c 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ECF21.