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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 © 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.2016.06.250 ∗ Corresponding author. Tel.: + 49 6151 16-26147, Fax: + 49 6151 16-26142 E-mail address: rosendahl@fsm.tu-darmstadt.de (P. L. Rosendahl). 2452-3216 c 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ECF21. Stress raisers such as open-h les or rounded notches can be found in almost any structure. Due to the local stress concentration, they constitute prominent locations for crack initiation. The non-singular nature of the stress field, however, leads to vanishing energy release rates such that classical fracture mechanics concepts as the Gri ffi th criterion (Gri ffi th, 1921) cannot be applied directly. An additional non-physical length parameter as e.g. an existing finite sized crack or internal flaw (Waddoups et al., 1971) needs to be assumed. In order to render size e ff ects, stress based criteria need to be evaluated at a certain distance from the stress concentration as proposed by Whitney and Nuismer (1974). In the framework of finite fracture mechanics (FFM), the need for an empirical length scale can be eliminated. Here, the instantaneous initiation of cracks of finite size is assumed if both, a stress and an energy criterion are satisfied simultaneously. This so-called coupled criterion proposed by Leguillon (2002) requires only the two fundamental material properties strength and fracture toughness to study the onset of brittle fracture. It allows for the assessment of arbitra y crack initiation patterns and provides the finite crack sizes as well as the critical load. ∗ Corresponding author. Tel.: + 49 6151 16-26147, Fax: + 49 6151 16-26142 E-mail address: rosendahl@fsm.tu-darmstadt.d (P. L. Rosendahl). 2452-3216 c 2016 The Authors. Publi hed by Elsevier B.V. e r-review under responsibility of the Scientific Committee of ECF21. Stress raisers such as open-holes or rounded notches can be found in almost any str cture. Due to t e local stress c ncentration, they constitute prominent locations for crack initiation. Th no -singular nature of the stress field, however, leads to vanishing energy release rates such that classical fracture mechanics concepts s the Gri ffi th criterion (Gri ffi th, 1921) cannot be applied directly. An additional non-physica length parameter as e.g. an existing finite sized crack r internal flaw (Waddoups et al., 1971) needs to be assumed. In order t render size e ff ects, stress based criteria need to be valuated at a certain distance from the stress concentration as proposed by Whitney and Nuismer (1974). In the framew rk of finite fracture mechanics (FFM), the nee for an empirical length scale can be eliminated. Here, the instantaneous initiation of cracks of finite size is assumed if both, a stress and an nerg criterion are satisfied simult neously. This so-calle coupled criterion proposed by Leguillon (2002) requires only the two fundamental material properties strength and fr cture toughness to study the onset of brittle fracture. It allows for the assess ent of arbitrary crack initiation patterns and provides the finite crack sizes as well as the critical load. ∗ Corresponding author. Tel.: + 49 6151 16-26147, Fax: + 49 6151 16-26142 E-mail address: rosendahl@fsm.tu-darmstadt.de (P. L. Rosendahl). 2452-3216 c 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility 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, June 20–24, 2016, Catania, Italy A numerical finite fracture mechanics approach on asymmetric cracks in open-hole plates P. L. Rosendahl a, ∗ , P. Weißgraeber b , N. Stein a , W. Becker a a Technische Universität Darmstadt, Fachgebiet Strukturmechanik, Franziska-Braun-Str. 7, 64287 Darmstadt, Germany b Robert Bosch GmbH, Corporate Research and Advance Engineering, Renningen, Germany Abstract Using an e ffi cient umeri al approach, a model rendering the initiati n of asymm tric crack patterns in open-hole plates subject to combined tensile and in-plane bending loading is presented. In the framework of finite fracture mechanics a stress and an energy criterion are enforced simultaneously and used as a coupled condition for the formation of cracks of finite size. Using closed-form expressions for the dependence of the stress and energy quantities needed to solve the coupled criterion on the structural and material parameters, only a limited number of linear elastic finite element analyses is required for a comprehensive analysis of the notched plate. The failure load predictions of the presented model are shown to agree well with experimental results and predictions of a cohesive zone model. The finite fracture mechanics approach allows for a study of crack patterns associated to failure. c 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ECF21. Keywords: Finite fracture mechanics, asymmetric cracks, brittle fracture, size e ff ect 1. Introduction Stress raisers such as open-holes or rounded notches can be found in almost any structure. Due to the local stress concentration, they constitute prominent locations for crack initiation. The non-singular nature of the stress field, however, leads to vanishing energy release rates such that classical fracture mechanics concepts as the Gri ffi th criterion (Gri ffi th, 1921) cannot be applied directly. An additional non-physical length parameter as e.g. an existing finite sized crack or internal flaw (Waddoups et al., 1971) needs to b assumed. In order to render size e ff ects, stress based criteria need to be evaluated at a certain distance from the stress concentration as proposed by Whitney and Nuismer (1974). In the framework of finite fracture mechanics (FFM), the need for an empirical length scale can be eliminated. Here, the instantaneous initiation of cracks of finite size is assumed if both, a stress and an energy criterion are satisfied simultaneously. This so-called coupled criterion proposed by Leguillon (2002) requires only the two fundamental material properties strength and fracture toughness to study the onset of brittle fracture. It allows for the assessment of arbitrary crack initiation patterns and provides the finite crack sizes as well as the critical load. 21st European Conference on Fracture, ECF21, June 20–24, 2016, Catania, Italy A numerical finite fracture mechanics appro ch on asymmetric cracks in open-hole plates P. L. Rosendahl a, ∗ , P. Weißgraeber b , N. Stein a , W. Becker a a Technische Universität Darmstadt, Fachgebiet Strukturmechanik, Franziska-Braun-Str. 7, 64287 Darmstadt, Germany b Robert Bosch GmbH, Corporate Research and Advance Engineering, Renningen, Germany Abstract Using an e ffi cient numerical approach, a model rendering the initiation of asymmetric crack patterns in open-hole plates subject to combined tensile and in-plane bending loading is presented. In the framework of finite fracture mechanics a stress and an energy criterion are enforced simultaneously and used as a coupled condition for the formation of cracks of finite size. Using closed-form expressions for the dependence of the stress and energy quantities needed to solve the coupled criterion on the structural and material parameters, only a limited number of linear elastic finite element analyses is required for a comprehensive analysis of the notched plate. The failure load predictions of the presented model are shown to agree well with experimental results and predictions of a cohesive zone model. The finite fracture mechanics approach allows for a study of crack patterns associated to failure. c 2016 The Authors. Publis ed by Elsevi r B.V. Peer-review under responsibility of the Scientific Committee of ECF21. Keywords: Finite fracture mechanics, asymmetric cracks, brittle fracture, size e ff ect 1. Introduction 21st European Conference on Fracture, ECF21, June 20–24, 2016, Catania, Italy A numerical finite fracture mechanics approach on asymmetric cracks in open-hole plates P. L. Rosendahl a, ∗ , P. Weißgraeber b , N. Stei a , W. Becker a a Technische Universität Darmstadt, Fachgebiet Strukturmechanik, Franziska-Brau -Str. 7, 64287 Darmstadt, Germany b Robert Bosch GmbH, Corpor te R search and Advance Engin erin , Renningen, Germany Abstract Using an e ffi cient numerical approach, a model rendering the initiation of asymmetric crack patterns in open-hole plates subject to combined tensile and in-plane bending loading is presented. In the framework of finite fracture mechanics a stress and an energy criterion are enforced simultaneously and used as a coupled condition for the formation of cracks of finite size. Using closed-form expressions for the dependence of the stress and energy quantities needed to solve the coupled criterion on the structural and material parameters, only a limited number of linear elastic finite element analyses is required for a comprehensive analysis of the notched plate. The failure load predictions of the presented model are shown to agree well with experimental results and predictions of a cohesive zone model. The finite fracture mechanics approach allows for a study of crack patterns associated to failure. c 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ECF21. Keywords: Fi ite fracture mechanics, asymmetric cracks, brittle fracture, size e ff ect 1. Introduction 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/). r-review under responsibility 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. * Corresponding author. Tel.: +351 218419991. E-mail address: amd@tecnico.ulisboa.pt