PSI - Issue 13

ScienceDirect Available online at www.sciencedirect.com Av ilable o line at www.sciencedirect.com ienceDirect Structural Integrity Procedia 00 (2016) 000 – 000 Procedia Structu al Integrity 13 (2018) 243–248 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2018) 000 – 000 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2018) 000 – 000

www.elsevier.com/locate/procedia www.elsevier.com/locate/procedia

www.elsevier.com/locate/procedia

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. ECF22 - Loading and Environmental effects on Structural Integrity Investigation and Modeling of Local Crack Arrest in Ferritic Bainitic Steels Under Dynamic Loading Johannes Tlatlik*, Dieter Siegele Fraunhofer Institute for Mechanics of Materials IWM, Wöhlerstr. 11, 79108, Freiburg, Germany Abstract Local crack arrest is usually irrelevant under quasi-static loading conditions in the ductile to brittle transition region. levated loading rates, howeve , allow cleavage fracture due to th dynamic embrittlement also at higher testing temperatures compared to static loading. This behavior is generally accompanied by local crack arrest events. In addition, adiabatic heating processes in the crack tip region increase local temperature as well, which further promotes crack arrest. This complex interaction between crack initiation and crack arrest at elevated loading rates substantially changes macroscopic fracture behavior, whereas its investigation is the core of this work. An experimental database of dynamic fracture mechanics experiments for the reactor pressure vessel steel 22NiMoCr3-7 is examined in this work that was previously tested at crack tip loading rates of about 10 3 to 10 5 MP a√ m /s. Recent fractographic examinations and st tistics regarding the occurr nce a d cha acteristics f local crack arrest incidences are shown for different loading rates and testing temperatures. Furthermore, an existing local probabilistic cleavage fracture model is used to describe macroscopic fracture behavior for the provided experimental database, and also compared to other assessment methods (i.e. Master Curve). The shortcomings in the numerical assessment methods can be linked to the amount of observed local cr ack arrest incidences, and a micromechanically motivated model modification is proposed to consider the mechanism of local crack arrest. The agreement between experi ental results and numerical cleavage fracture assessment can be significantly increased by using the modified model. ECF22 - Loading and Environmental effects on Structural Integrity Investigation and Modeling of Local Crack Arrest in Ferritic Bainitic Steels Under Dynamic Loading Johannes Tlatlik*, Dieter Siegele Fraunhofer Institute for Mechanics of Materials IWM, Wöhlerstr. 11, 79108, Freiburg, Germany Abstract Local crack arrest is usually irrelevant under quasi-static loading conditions in the ductile to brittle transition region. Elevated loading rates, however, allow cle vage fracture due to the dynamic embrittlement also at higher t sting temp r tur s comp red t static loading. This behavi r is generally accompanied by local crack arrest events. In addition, adiabatic heating processes in t e crack t p region increase l cal temperature s well, which further promotes crack arrest. This complex interaction between crack initiation and crack arrest at elevated loading rates substantially changes macroscopic f ure havior, whereas ts i vestigation is the cor of this work. An experimental database of dynami fra ture mechanics experiment for the reactor pre sur vessel steel 22NiMoCr3-7 is xamined in this work that was previously tested at crack tip loading rates of about 10 3 to 10 5 MP a√ m /s. R cent fractographic examination and statistics r garding the occurrence and char cteristics of local cr ck arrest inciden es are shown for differe t lo ding rat s and testing temper tures. Furthermore, an existing loc l probabilisti cleavage fracture model is used to describe macroscopic fr cture behavior for the prov ded experimenta database, and lso co pared to other as essment meth ds (i.e. Master Curve). Th sh rtcomings in the numerical assessment methods can be linked to the amount of observed local cr ack arrest incidences, and a micromechanically motivated model modification is proposed to consider the mechanism of lo al crack rrest. The agreement between experimental results and numerical cleavage fracture ass ssment can be sig ificantly increased by usi g the modified model. © 2018 The Authors. Published by Els v er B.V. Peer-review under espons bility of the ECF22 organizers. © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of PCF 2016. © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsib lity of the ECF22 organizers. © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. Keywo ds: cleavage fracture, dynamic frac ure mechanics, crack arr st, local approach, finite-element-method

Keywords: High Pressure Turbine Blade; Creep; Finite Element Method; 3D Model; Simulation. Keywords: cleavage fracture, dynamic fracture mechanics, crack arrest, local approach, finite-element-method

* 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. 2452-3216 © 2018 The Authors. Published by Elsevier B.V. Peer review under r sponsibility of the ECF22 o ganizers. * Corresponding author. Tel.: +49-761-5142-105; fax: +49-761-5142-401. E-mail address: johannes.tlatlik@iwm.fraunhofer.de * Corresponding author. Tel.: +49-761-5142-105; fax: +49-761-5142-401. E-mail ad ress: jo annes.tlatlik@iwm.fraunhofer.de

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

2452-3216  2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. 10.1016/j.prostr.2018.12.041