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2452-3216 © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of PCF 2016. Copyright © 2017 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 IGF Ex-Co. 10.1016/j.prostr.2017.04.062 ∗ Corresponding author. Tel.: + 46-2223990. E-mail address: per.stahle@solid.lth.se 2452-3216 c 2017 The Author . Published by Els vier B.V. Peer-review under responsibility of the Scientific Committee of IGF Ex-Co. Zirconium alloys are frequently used as a part of structural material in the core of nuclear reactors because of its high strength, corrosion resistance at high temperatures and especially because of its small cross section for thermal neutrons, cf. Cochran et al. (1990). The latter property means that interference between the material and the reactor operation is avoided. However, failures that are associated with hydrogen is a weakness that has lead to accidents in ∗ Corresponding author. Tel.: + 46-2223990. E-mail address: per.stahle@solid.lth.se 2452-3216 c 2017 The Authors. Published by Elsevier B.V. eer-review under responsibility of the Scientific Committee of IGF Ex-Co. Zirconium alloys are frequently used as a part of structural material in the core of nuclear reactors because of its high strength, corrosion resista ce at high temperatures and especially because of its small cross section for thermal neutrons, cf. Cochran et al. (1990). T e latter property means that interference between the material and the reactor operation is av ided. However, failures that are associated with hydrogen is a weakness t at has lead to accidents in ∗ Corresponding author. Tel.: + 46-2223990. E-mail address: per.stahle@solid.lth.se 2452-3216 c 2017 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of IGF Ex-Co. i p ase field model. Bef re the material is transfor ed and incorporated in a precipitate it undergoes stretching beyond the ela ti strain limit because of the presence of already expan ed material. During the pha t tion, the accomp i l t i i t ll ommodated which inst t i t l i t t i i t i material. As the growth of the pr cipitate proceeds, a i it i i t il t l i t i t i t i it t . i i t t t m l t . i t t i t t l t t t i i t . i l ti l ti ti i tudied both f r cas t it it t . t i t i i t i i it t is foll t lt i it ti ll i li t t t i i ll i t e of h . ti l it ti i t i i i i t t it object of lower temperature. Then the cooled spot tt t t at make the zirconium transform to a etal hydride ith th li t . i l ti i t l i iti t i t t ll it t i t l observations. c 2017 The t r . li l i . . i i ilit t i ti itt . ri ; fr t r ; li t r; l t; . i i i ll tl t t t l t i l i t l t it i t t , i i t t i t t i ll it l ti t l t , . t l. . l tt t t t i t t t t i l t t ti i i . , il t i t it i t l t i t i ∗ rr i t r. l.: 46-222 . - ail address: r. t l li .lt . - c 2017 The Authors. Published by Else i r . . Peer-review under responsibility of the Scientific C itt f I - . Copyright © 2017 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/). P r-review under responsibility of the Scientific Committee of IGF Ex-Co. 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. XXIV Italian Group of Fracture Conference, 1-3 March 2017, Urbino, Italy Phase Field Modelling of Formation and Fracture of Expanding Precipitates W. Reheman a , P. Ståhle a, ∗ , E. Durge´ a , R.N. Singh b a Division of Solid Mechanics, Lund University, SE22100 Lund, Sweden b Materials Science Division, Bhabha Atomic Research Centre, Mumbai, India Abstract It is a common belief that embedded expanding inclusions are subjected to an internal homogeneous compressive hydrostatic stress. Still, cracks that appear in precipitates that occupy a larger volume than the original material, are frequently observed. The appearance of cracks has sinc long been rega ded as a paradox. In the present study it is shown that matrix materials that increases its volume even several percent during the precipitation process develop a tensile hydrostatic stress in the centre of the precipitate. This is the result of a complicated mechanical-chemical phase transformation process. The process is here studied using a Landau phase field model. Before the material is transformed and incorporated in a precipitate it undergoes stretching beyond the elastic strain limit because of the presence of already expanded material. During the phase transformation, the accompanying volumetric expansion cannot be fully accommodated which instead creates an internal compressive stress and adds tension in the surrounding material. As the growth of the precipitate proceeds, a region with increasing tensile stress develops in the interior of the precipitate. This is suggested to be the most probable cause of the observed cracks. First the mechanics that lead to the tension is computed. The influence of elastic-plastic properties is studied both for cases both with and without cracks. The growth history from microscopic to macroscopic precipitates is followed and the result is compared with observations of so called hydride blisters that are formed on surfaces of zirconium alloys in the presence of hydrogen. A common practical situation is when the zirconium is in contact with an object of lower temperature. Then the cooled spot attracts hydrogen that make the zirconium transform to a metal hydride with the shape of a blister. The simulations predicts a final size and position of the growing crack that compares well with the experimental observations. c 2017 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of IGF Ex-Co. Keywords: Hydride; fracture; blister; cold spot; XXIV Italian Group of Fracture Conference, 1-3 March 2017, Urbino, Italy Phase Field Modelling of Formation and Fracture of Expanding Precipitates W. Reheman a , P. Ståhle a, ∗ , E. Durge´ a , R.N. Singh b a Division of Solid Mechanics, Lund University, SE22100 Lund, Sweden b Materials Science Division, Bhabha Atomic Research Centre, Mumbai, India Abstract It is a common belief that embedded expanding in lusions ar subject d to an internal homogeneous compressive hydrostatic stress. Still, cracks hat appear in precipitates that occupy a larger volume than the original material, are frequently observed. The appearance of cracks has since long been regarded as a paradox. In he resent stud it is shown that matrix mat rials that increas s its volum even several percent during the precipitation rocess develop a te sile hydrostatic str s in the centre of the precipitate. Thi is the result of a complicated mechanical-chemical phase transformation process. The process is here studied using a Landau ph se field model. Before th material is transformed and incorporated in a precipitate it undergoes stretching beyond the elastic strai limit because of the presence of already expanded material. During the phase tran formation, the accompanying volumetric expansion cannot be fully acc mmodated which i stead creates an internal compressive stress and adds tension in the surrounding material. As the growth of the precipitate proceeds, a region with increasing tensile stress develops in the interior of the precipitate. This is suggested to be the most probable cause of the bserved cracks. First the mechanics that l ad to the tension is computed. The influence of elastic-plastic properties is studied both for cases both with and without cracks. The growth hi tory from microscopic to macroscopic precipitates is followed and the result is compared with observations of so called hydride blisters that are formed on surfaces of zirconium alloys in the presenc of hydrogen. A common practical situation is when the zirconium is in contact with an object of lower temperature. Then the cooled spot attracts hydrogen that make the zirconium transform to a metal ydride with the shape of a blister. The simulations predicts a final size and position of the growing crack that compares well with the experimental observations. c 2017 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of IGF Ex-Co. Keywords: Hydride; fracture; blister; cold spot; XXIV Italian Group of Fracture Conference, 1-3 arch 2017, Urbino, Italy Phase Field odelling of Formation and Fracture of xpanding Precipitates . Rehe an a , P. Ståhle a, ∗ , E. Durge´ a , R.N. Singh b a Division of Solid Mechanics, Lund University, SE22100 Lund, Sweden b M terials Science Division, Bhabha Atomic Research Centre, Mumbai, India Abstract It is a common belief that embedded expanding inclusions are subjected to an internal homogeneous compressive hydrostatic stress. Still, cracks that appear in precipitates that occupy a larger volume than the original material, are frequently observed. The appearance of cracks has since long been regarded as a paradox. In the present study it is shown that matrix materials that increases its volume even several percent during the precipitation process develop a tensile hydrostatic stress in the centre of the precipitate. This is the result of a complicated mechanical-chemical phase transformation process. The process is here studied using a Landau phase field model. Before the material is transformed and incorporated in a precipitate it undergoes stretching beyond the elastic strain limit because of the presence of already expanded material. During the phase transformation, the accompanying volumetric expansion cannot be fully accommodated which instead creates an internal compressive stress and adds tension in the surrounding material. As the growth of the precipitate proceeds, a region with increa ing tensile stress develops in the interior of the precipitate. This is suggested to be the most probable cause of the observed crack . Fir t the mechanics that lead to the tension is computed. The influence of elastic-plastic prope ties is studied both for cases both with and without crack . The growth history from microscopic to macroscopic precipitates is followed and the result is compared with observations of so c lled hydride blisters that are formed on surfaces of zirconi m alloys in the pr sence of hydrogen. A comm n practical situation is when the zirconium is in con act with an obj ct of lower temperature. Then the cooled spot attracts hydrogen that make the zir onium transf rm to a e al hydride w th the shape of a blist r. The simul tions predicts a nal size and position of the growing crack that compares well with the experimental observations. c 2017 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of IGF Ex-Co. Keywords: Hydride; fracture; blister; cold spot; a . a le a, a , b a i i i f li i , i it , , t i l i i i i , t i t , i, Indi t i li t t i i l i j t t i t l i t ti t . till, t t i i it t t t l l t t i i l t ial, are frequently o . appearance of cracks has since long been regarded as a p . t t t it i t t t i t i l t t i its volume even several percent during the precipitatio l t il t ti t i t t t i it t . This is the result of a complicated mechanical-chemical phase tran ti . i t i © 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 1. Introduction 1. Introduction 1. Introduction Zirconium alloys are frequently used as a part of structural material in the core of nuclear reactors because of its high strength, corrosion resistance at high temperatures and especially because of its small cross section for thermal neutrons, cf. Cochran et al. (1990). The latter property means that interference between the material and the reactor operation is avoided. However, failures that are associated with hydrogen is a weakness that has lead to accidents in