PSI - Issue 2_A

ScienceDirect Available online at www.sciencedirect.com Av ilable online at ww.sciencedire t.com cienceDirect Structural Integrity Procedia 00 (2016) 000 – 000 Procedia Structural Integrity 2 (2016) 1577–1584 Available online at www.sciencedirect.com Structural Integrity Procedia 00 (2016) 000–000 Available online at .s ie di e t.c Structural Integrity Procedia 00 (2016) 000–000 Available online at www.sciencedirect.co Structural Integrity Procedia 00 (2016) 000–000

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

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.2016.06.200 ∗ Corresponding author. Tel.: + 55-11-3091-5184 ; fax: + 55-11-3091-5717. E-mail address: claudio.ruggieri@usp.br 2452-3216 c 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ECF21. Structural integrity asse sment proc dures for co mercial reactor pressure vessels (RPVs) focus on he utilization of small fracture specimens to facilit te experimental measurements of fracture toughness data. In p rticular, three point bend testing of precracked Charpy (PCVN) spec mens bec mes necessary when severe limitations exist on materi l availability such as, for example, in nuclear irradiation embrittlement studies. A recently devel p d procedure to characterize fractu e toughness da a ( J c or K Jc ) over the ductile-to-brittle transition (DBT) region, often known as the Master Curve approach, makes extensive u e in ractic of PCVN specimens to determine a ref rence temperature, T 0 , and the associated median fracture toughness applicable to a wide range of structural ferritic ste ls. However, as the specimen size i reduced (relative to the standard 1T specimen), the evolving crack-tip plastic zones dev loping f om he free surfaces with increased loading a ff cts strongly the crack-fron size over which high level of near-tip stress triaxiality (constraint) are maintained. These changes in the crack-tip stress fields over a relatively small thickness in ∗ Corresponding author. Tel.: + 55-11-3091-5184 ; fax: + 55-11-3091-5717. E-mail address: claudio.ruggieri@usp.br 2452-3216 c 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ECF21. Abstract This work describes a modified eibull stress ( ˜ σ w ) approach incorporating the potentially strong e ff ects of plastic strain on cleavage fracture. The primary purpose of this study is to explore application of a probabilistic-based micromechanics model incorporat ing e ff ects of plastic strain on cleavage fracture to determine the reference temperature for pressure vessel steels from precracked Charpy (PCVN) specimens. Fracture toughness tests conducted on an A515 Grade 65 pressure vessel steel provide the cleav age fracture resistance data needed to assess specimen geometry e ff ects on J c -values . Calibration of the modified eibull stress parameters provides the relationship between ˜ σ w and macroscopic load (in terms of the J -integral) from which the variation of frac ture toughness across di ff erent crack configurations is predicted. For the tested material, the modified eibull stress methodology e ff ectively removes the geometry dependence of fracture toughness. c 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ECF21. Keywords: Cleavage Fracture; Local Approach; eibull Stress; Plastic Strain; Probabilistic Fracture Mechanics 1. Introduction Structural integrity asse s ent procedures for co ercial reactor pressure vessels (RP s) focus on the utilization of s all fract re speci ens to facilitate experi ental easure ents of fracture toughness data. In particular, three point bend testing of precracked Charpy (PC ) speci ens beco es necessary hen severe li itations exist on material availability such as, for exa ple, in nuclear irradiation e brittle ent studies. recently developed procedure to characterize fracture toughness data ( J c or K Jc ) over the ductile-to-brittle transition ( BT) region, often kno n as the aster Curve approach, akes extensive use in practice of PC speci ens to deter ine a reference te perature, T 0 , and the associated edian fracture toughness applicable to a ide range of structural ferritic steels. o ever, as the speci en size is reduced (relative to the standard 1T speci en), the evolving crack-tip plastic zones developing fro the free surfaces ith increased loading a ff ects strongly the crack-front size over hich high levels of near-tip stress triaxiality (constraint) are maintained. These changes in the crack-tip stress fields over a relatively s all thickness in ∗ Corresponding author. Tel.: + 55-11-3091-5184 ; fax: + 55-11-3091-5717. E-mail address: claudio.ruggieri usp.br 2452-3216 c 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ECF21. Copyright © 2016 The Author . Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://cr ativecommons.org/licenses/by-nc-nd/4.0/). review under esponsibility of the Scientific Committee of ECF21. 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 A Modified Weibull Stress Approach to Predict Specimen Geometry E ff ects in a Pressure Vessel Steel Claudio Ruggieri a, ∗ , Robert H. Dodds b a University of Sao Paulo, PVN-EPUSP, Sao Paulo 05508-030, Brazil b University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States Abstract This work describes a modified Weibull stress ( ˜ σ w ) approach incorporating the potentially strong e ff ects of plastic strain on cleavage fracture. The primary purpose of this study is to explore application of a probabilistic-based micromechanics model incorporat ing e ff ects of plastic strain on cleavage fracture to determine the reference temperature for pressure vessel steels from precracked Charpy (PCVN) specimens. Fracture toughness tests conducted on an A515 Grade 65 pressure vessel steel provide the cleav age fracture resistance data needed to assess specimen geometry e ff ects on J c -values . Calibration of the modified Weibull stress parameters provides the relationship between ˜ σ w and macroscopic load (in terms of the J -integral) from which the variation of frac ture toughness across di ff erent crack configurations is predicted. For the tested material, the modified Weibull stress methodology e ff ectively removes the geometry dependence of fracture toughness. c 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ECF21. Keywords: Cleavage Fracture; Local Approach; Weibull Stress; Plastic Strain; Probabilistic Fracture Mechanics 1. Introduction Structural integrity assessment procedures for commercial reactor pressure vessels (RPVs) focus on the utilization of small fracture specimens to facilitate experimental measurements of fracture toughness data. In particular, three point bend testing of precracked Charpy (PCVN) specimens becomes necessary when severe limitations exist on material availability such as, for example, in nuclear irradiation embrittlement studies. A recently developed procedure to characterize fracture toughness data ( J c or K Jc ) over the ductile-to-brittle transition (DBT) region, often known as the Master Curve approach, makes extensive use in practice of PCVN specimens to determine a reference temperature, T 0 , and the associated median fracture toughness applicable to a wide range of structural ferritic steels. However, as the specimen size is reduced (relative to the standard 1T specimen), the evolving crack-tip plastic zones developing from the free surfaces with increased loading a ff ects strongly the crack-front size over which high levels of near-tip stress triaxiality (constraint) are maintained. These changes in the crack-tip stress fields over a relatively small thickness in 21st European Conference on Fracture, ECF21, 20-24 June 2016, Catania, Italy A Modified Weibull Stress Approach to Predict Specimen Geometry E ff ects in a Pressure Vessel Steel Claudi Ruggieri a, ∗ , Robert H. Dodds b a University of Sao Paulo, PVN-EPUSP, Sao Paulo 05508-030, Brazil b University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States Abstract This work d sc bes a modified Weibull stress ( ˜ σ w ) approach incorp rating the potentially strong e ff ects of plastic strain on cleavage fracture. The primary purp se of this study is to explore application of a probabilistic-based micromechanics model inco porat ing e ff ects of plastic strain on cleavage fracture to determine the reference temperature for pressure vessel steels from precracked Charpy (PCVN) specimens. Fracture toughness tests conduc ed on an A515 Grade 65 pressure vessel steel provid the cleav age fracture esistance dat needed to assess specimen geometry e ff ects on J c -values . Calibration of the modified Weibull st ess parameters provide the relationship between ˜ σ w and macroscopic load (in terms of the J -integral) from which the variation of frac ture oughn ss across di ff erent crack configurations is predicted. For the tested material, the modified Weibull stress methodology e ff ectively removes the geometry dependence of fracture tough ess. c 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ECF21. Keywords: Cleavage Fracture; Local Approach; Weibull Stress; Plastic Strain; Probabilistic Fracture Mechanics 1. Introduction 21st uropean onference on Fracture, F21, 20-24 June 2016, atania, Italy A i i ll tr ss Approach to Predict Specimen Geometry E ects in a Pr ss r ssel Steel Claudio Ruggieri a, ∗ , Robert H. Dodds b a University of Sao Paulo, PVN-EPUSP, Sao Paulo 05508-030, Brazil b University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States © 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