PSI - Issue 8

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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. Copyright © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of AIAS 2017 International Conference on Stress Analysis AIAS 2017 International Conference on Stress Analysis, AIAS 2017, 6–9 September 2017, Pisa, Italy Measurement and modelling of Bauschinger e ff ect for low-level plastic strains on AISI 4140 steel Matteo Lo ff redo a a Baker Huges, a GE company, Via Felice Matteucci, 2 , Firenze 50127, Italy. Abstract This paper presents a new model for reproducing the elasto-plastic behavior of metals characterized by the presence of Bauschinger e ff ect, taking as reference th c se of autofrettaged cylinders. The paper is composed of an experimental part and of a numerical part. The experimental part consists of a set of tension-compressi n tests performed on AISI 4140 investigating the level of plastic strains typical of autofrettage: experiment arrangement, load cycles, measurement procedure and relevant results are presented. In the numerical part a multiaxial elasto-plastic model, derived from a combination of non-linear Kinematic hardening and non-linear Isotropic softening, is formulated and the key points for implementing it in a commercial Finite Element code are discussed. Then a fitting procedure for model parameters is proposed for reproducing the results obtained in experimental part. In the end the model has been implemented in ANSYS software and an example of application is presented for the case of an autofrettaged cylinder. c 2017 The Authors. Published by Elsevier B.V. r-review unde responsibility of the Scientific Committee of AIAS 2017 International Co ference on Stress Analysis. Keywords: Bauschinger e ff ect, Autofrettage, Plasticity, Kinematic hardening, Isotropic softening, ANSYS User Programmable Features ; 1. Introduction Residual Stresses (RSs) can bring either beneficial or detrimental e ff ects to mechanical components. In general, when RSs are introduced intentionally they are compressive at the surface since the most common goal is increasing component’s fatigue life. Such a RS state is usually achieved by overloading the component above the elastic limit: the beneficial RS state is created after unloading. A typical example is the autofrettage process (Hill (1950)), that finds its application in components subjected to high pressure loading like cannon barrels, nuclear reactors, reciprocating compressors and cold worked holes. These components, during autofrettage process are loaded above the elastic limit at their bore through imposed radial deformation or internal pressure. The beneficial e ff ect comes about at the unload ing phase when a compressive hoop RS is created locally at the bore. AIAS 2017 International Conference on Stress Analysis, AIAS 2017, 6–9 September 2017, Pisa, Italy easure ent and odelling of Bauschinger e ff ect for low-level plastic strains on AISI 4140 steel Matteo Lo ff redo a a Baker Huges, a GE company, Vi Felice Matteucci, 2 , Firenze 50127, Italy. Abstract This paper presents a new model for reproducing the elasto-plastic behavior of metals characterized by the presence of Bauschinger e ff ect, taking as reference the case of autofrettaged cylinders. The paper is composed of an experimental part and of a numerical part. The experimental part consists of a set of tension-compression tests performe on AISI 4140 investigating the level of plastic strains typical of autofrettage: experiment arrangement, load cycles, measurement procedure and relevant results are presented. In the numerical part a multiaxial elasto-plastic model, derived from a combination of non-linear Kinematic hardening and non-linear Isotropic softening, is formulated and the key points for implementing it in a commercial Finite Element code are discussed. Then a fitting procedure for model parameters is proposed for reproducing the results obtained in experimental part. In the end the model has been implemented in ANSYS software and an example of application is presented for the case of an autofrettaged cylinder. c 2017 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of AIAS 2017 International Conference on Stress Analysis. Keywords: Bausching r e ff ect, Autofrettage, Plasticity, Kinem tic hardening, Isotropic softenin , ANSYS User Programmabl F atur s ; 1. Introduction Residual Stresses (RSs) can bring either beneficial or detrimental e ff ects to mechanical components. In general, when RSs are introduced intentionally they are compressive at the surface since the most common goal is increasing component’s fatigue life. Such a RS state is usually achieved by overloading the component above the elastic limit: the beneficial RS state is created after unloading. A typical example is the autofrettage process (Hill (1950)), that finds its application in components subjected to high pressure loading like cannon barrels, nuclear reactors, reciprocating compressors and cold worked holes. These components, during autofrettage process are loaded above the elastic limit at their bore through imposed radial deformation or internal pressure. The beneficial e ff ect comes about at the unload ing phase when a compressive hoop RS is created locally at the bore. © 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 ∗ Corresponding author. Tel.: + 39-055-458-3336 ; fax: + 39-055-423-2800. E-mail address: matteo.lo ff redo@bhge.com ∗ Corresponding author. Tel.: + 39-055-458-3336 ; fax: + 39-055-423-2800. E-mail address: matteo.lo ff redo@bhge.com

2452-3216 © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of PCF 2016. 2210-7843 c 2017 The Authors. Published by Elsevier B.V. Peer-revi w under responsibility of the Scientific Committee of AIAS 2017 International Conference on Stress Analysis. 2210-7843 c 2017 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of AIAS 2017 International Conference on Stress Analysis. 2452-3216 Copyright  2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of AIAS 2017 International Conference on Stress Analysis 10.1016/j.prostr.2017.12.028