PSI - Issue 13

ScienceDirect Available online at www.sciencedirect.com Available online at ww.sciencedire t.com cienceDirect Structural Integrity Procedia 00 (2016) 000 – 000 Procedia Structural Integrity 13 (2018) 1135–114 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2018) 000–000 Available online at www.sciencedirect.com ScienceDirect Structural I t grity 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. ECF22 - Loading and Environmental effects on Structural Integrity Reference toughness – a pragmatic tool to estimate ductile-brittle transition temperatures Sakari Pallaspuro a,b, *, Saara Mehtonen c , Jukka Kömi a , Zhiliang Zhang b and David Porter a a Materials and Production Engineering, Centre for Advanced Steels Research, University of Oulu, Finland b Department of Structural Engineering, Faculty of Engineering Science and Technology, NTNU, Norway c SSAB, Raahe, Finland Abstract Recent advances show that tough as-quenched ultra-high-strength steels in fully and partially martensitic conditions demand proper control of the effective coarse grain size, which is the key microstructural parameter controlling the toughness in the ductile-brittle transition region. The most effective way to reduce this grain size and texture components detrimental to toughness with thermomechanically rolled steels is to apply a high level of austenite pancaking. The effective coarse grain size (d 80% ) can be used to reliably estimate impact toughness transition temperatures. Adding the fraction of {100} cleavage planes close to the specimen notch/crack plane further improves these estimates. A recent straightforward semi-physical model consists of just two parameters, the fi st term describes the temp rature-dependency of a local brittle fractur , and he se ond term relates to the siz of these locally cleav d reas. Here, w present th concept ref rence toughness and tudy its pplicability t the estimation of both impact toughness a d fracture toughness transition temperatures. Fractographic evidence demonstrates that failure initiation is a complicated interaction between large grains an large brittle inclusions. With locally varying, inhomogeneous icrostructural properties, the failure is likely to initiate and propagate when a large particle locates in a coarse-grained matrix, whose dimensions are in line with the effective coarse grain size. Application of these microstructure-based estimates of the impact toughness and fracture toughness transition temperatures can further assist the design and production of steels with lath-like microstructures. © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. © 2018 The Authors. Published by Elsevier B.V. Peer-review und r r sponsibility of the ECF22 organizers. ECF22 - Loading and Environmental effects on Structural Integrity Reference toughness – a pragmatic tool to estimate ductile-brittle transition temperatur s Sakari Pallaspuro a,b, *, Saara Mehtonen c , Jukka Kömi a , Zhiliang Zhang b and David Porter a a Materials and Production Engineering, Centre for Advanced Steels Research, University of Oulu, Finland b Departme t of Str tural ineeri , Faculty of Engi e ring Science nd Technolog , NTNU, Norway c SSAB, Raahe, Finla d Abstract Recent advances show that tough as-quenched ultra-high-strength steels in fully and partially martensitic conditions demand proper control of the effective coarse rain siz , which is the key microstructural parameter controlling the toughness in the ductile-brittle tra sition region. Th most effective way to reduce this grain size and texture components detrimental to toughness with thermomechanically rolled ste ls is to appl a high level of auste ite pancaking. The effective coars grain size (d 80% ) can be used to reliably estimate impact toughness transition temperatures. Adding the fraction of {100} cleavag pl nes close to the specim n notch/cr k plane further improves these estimat s. A recent straightforward semi-physical model consists of just two parameters, the first term describes the temperatur -dependency of a local brittle fracture, and the second term relates to the size of these locally cl aved areas. Here, we present the concept reference toughness and study its applicability to the estimation of both impact toughness and fracture tough ess transition temperatures. Fractographic evidence demonstrates that failure initiation is a complicated interaction between large grains and large brittle in lusions. With locally varying, inhomogeneous microstructural properties, the failure is likely to initiate and propag te when a large particle locates in a coarse-grained matrix, whose dimensions are in line with the ffective coarse grain size. Application of these microstructure-based estimates of the impact toughn ss and fracture toughness transition temperatures can further assist the d sign and production of st els with lath-like microstructures. © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers.

© 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of PCF 2016. Keywords: Ductile-brittle transition; Stress intensity; Fracture toughness; Impact toughness; Grain size; Characterization Keywords: Ductile-brittle transition; Stress intensity; Fracture toughness; Impact toughness; Grain size; Characterization

Keywords: High Pressure Turbine Blade; Creep; Finite Element Method; 3D Model; Simulation.

* Corresponding author. Tel.: +358-294-487-481. E-mail address: sakari.pallaspuro@oulu.fi * Corresponding author. Tel.: +358-294-487-481. E-mail ad ress: saka i.pa laspuro@oulu.fi

* 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 organizers.

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.2018.12.237