PSI - Issue 13

ScienceDirect Available online at www.sciencedirect.com Av ilable o line at ww.sciencedire t.com ienceDirect Structural Integrity Procedia 00 (2016) 000 – 000 Procedia Structu al Integrity 13 (2018) 855–861 Available online at www.sciencedirect.com Structural Integrity Procedia 00 (2018) 000–000 Available online at www.sciencedirect.com Structural Integrity Procedia 00 (2018) 000–000

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

ECF22 - Loading and Environmental e ff ects on Structural Integrity ECF22 - Loading and Environmental e ff ects on Structural Integrity

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. A numerical and experimental investigation of dynamic fracture in Polyamide 11: the e ff ect of the sample geometry Jean-Benoit Kopp a, ∗ , Christophe Fond b , Gilles Hochstetter c a I2M, Arts et Me´tiers Paris Tech, Esplanade des Arts et Me´tiers, F33800 Talence b ICube, Unive site´ de Strasbourg, 2 rue Bouss ngault, F67000 Strasbourg c Arkema France, 420 rue d’estienne d’orves, F92700 Colombes An experimental set-up and a numerical model are proposed to study the rapid crack propagation (RCP) resistance of polyamide 11 (PA11). Pipe and plate samples are studied. The solicitation type, imposed displacements or pressure, of polymer pipes is discussed. The necessity to pre-stress polymer pipe with imposed displacements is highlighted. Indeed, the work of external forces is not neg ligible for pressurized polymer pipes. A reliable estimate of the dynamic energy release rate G Id is in this last case not guaranteed. A new experimental set-up is used to Pre-Stress Pipe Specimen (PS2) in mode I. The crack is initiated artificially with an exter nal impact on a razor blade. A quasi-constant dynamic regime of propagation is then reached on about 20 cm. A finite element procedure is used to estimate G Id . Knowing the crack tip location during RCP inertia e ff ects i.e. kinetic energy are quantified. Numerical results reveal a higher dynamic correction fact r for a pipe (0.2) than a plate structure (0.9). An important and non negligible part of the stored ne gy is dissipate by the structure during RCP in pipe str cture. Crack tip locati n as a function of time is measur d wit the help of a high speed camera during dynamic regime of propagation. The calculated mean crack tip velocity is quasi-constant in PA11 whatever (i) the initial stored energy in the structure, (ii) the sample geometry and (iii) the crack configuration. This velocity is known to be the crack branching velocity (0.6 c R ). The dynamic energy release rate G Id is equal to 1.5 ± 0.1 kJ m − 2 for a pipe sample and 9.2 ± 0.7 kJ m − 2 for a plate sample at the crack branching velocity. Fracture surface analyses are leaded to explain this significant di ff erence. c � 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. © 2018 Th Authors. Published by Elsevier B.V. Peer-review und r r sponsibility f the ECF22 organizers. A numerical and experimental investigation of dynamic fracture in Polyamide 11: the e ff ect of the sample geometry Jean-Benoit Kopp a, ∗ , Christophe Fond b , Gilles Hochstetter c a I2M, Arts et Me´tiers Paris Tech, Esplanade des Arts et Me´tiers, F33800 Talence b ICube, Universite´ de Strasbourg, 2 rue Boussingault, F67000 Strasbourg c Arkema France, 420 rue d’estienne d’orves, F92700 Colombes Abstract An experimental set-up and a numerical model are proposed to study the rapid crack propagati n (RCP) resist nce of polyamide 11 (PA11). Pipe and plate samples are studied. The solicitation type, imposed displacements or pressure, of polymer pipes is discussed. The necessity to pre-stress polymer pipe with imposed displacements is highlighted. Indeed, the work f external forces is not neg ligible for pressurized polymer pipes. A reliable estimate of the dynamic energy release rate G Id is in this last case not guaranteed. A new experimental set-up is used to Pre-Stress Pipe Specimen (PS2) in mode I. The crack is initiated artificially with an exter nal impact on a razor blade. A quasi-constant dynamic regime of propagation is then reached on about 20 cm. A finite element procedure is used to estimate G Id . Knowing the crack tip location during RCP inertia e ff ects i.e. kinetic energy are quantified. Numerical results reveal a higher dynamic correction factor for a pipe (0.2) than a plate structure (0.9). An important and non negligible part of the stored energy is dissipated by the structure during RCP in pipe structure. Crack tip location as a function of time is measured with the help of a high speed camera during dynamic regime of propagation. The calculated mean crack tip velocity is quasi-constant in PA11 whatever (i) the initial stored energy in the structure, (ii) the sample geometry and (iii) the crack configuration. This velocity is known to be the crack branching velocity (0.6 c R ). The dynamic energy release rate G Id is equal to 1.5 ± 0.1 kJ m − 2 for a pipe sample and 9.2 ± 0.7 kJ m − 2 for a plate sample at the crack branching velocity. Fracture surface analyses are leaded to explain this significant di ff erence. c � 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. Keywords: Rapid crack propagation;Dynamic fracture;Energy released rate;Polymers;Pipes;Strip Band Specimen; Finite element; Inertia e ff ects; fracture surface analysis © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of PCF 2016. Keywords: Rapid crack propagation;Dynamic fracture;Energy released rate;Polymers;Pipes;Strip Band Specimen; Finite element; Inertia e ff ects; fracture surface analysi Abstract

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

1. Introduction 1. Introduction

Studying dynamic fracture in a material is not a simple matter. The main question is probably not why the crack is initiated and how much the energy release rate is necessary for that, but what is the minimal energy release rate necessary to ensure RCP in the material. If it is possible to answer this last question, it is possible to Studying dynamic fracture in a material is not a simple matter. The main question is probably not why the crack is initiated and how much the energy release rate is necessary for that, but what is the minimal energy release rate necessary to ensure RCP in the material. If it is possible to answer this last question, it is possible to

* Corresponding author. Tel.: +351 218419991. E-mail address: amd@tecnico.ulisboa.pt ∗ Corresponding author. Tel.: + 33 5 56 84 53 92 E-mail address: jean-benoit.kopp@ensam.eu ∗ Corresponding author. Tel.: + 33 5 56 84 53 92 E-mail address: jean-benoit.kopp@ensam.eu

2452-3216 © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of PCF 2016. 2210-7843 c � 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. 2210-7843 c � 2018 The Authors. Published by Elsevier B.V. Peer-revi w under responsibility of the ECF22 orga izers. 2452-3216  2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. 10.1016/j.prostr.2018.12.163