PSI - Issue 13

ScienceDirect Available online at www.sciencedirect.com Av ilable o line at www.sciencedire t.com ScienceDirect Structural Integrity Procedia 00 (2016) 000 – 000 Procedia Structu al Integrity 13 (2018) 862–867 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2018) 000 – 000 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2018) 000 – 000

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

www.elsevier.com/locate/procedia

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. © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. ECF22 - Loading and Environmental effects on Structural Integrity Calibration of constitutive equations for the stress level estimation in domain with the large strains Andrzej Neimitz a,* , Ihor Dzioba a , Sebastian Lipiec a a Kielce University of Technology, Al.1000-lecia P.P.7, 25-314 Kielce, Poland Abstract In the paper the calibration technique of the true stress - logarithmic strain curves is proposed, based on the modified Bai Wierzbicki method. Calibration w s done using four various specimen geometries selected to provide a wide range of stress triaxialities and Lode parameters. The level of plasticity was controlled by selection of three various materials tested at three temperatures: +20 º C, -20 º C, -50 º C. Modification of Bai-Wierzbicki method includes another way of computing the stress triaxiality and Lode parameter, taking into account the evolution of these parameters during the loading process. Also the material softening was included before the final failure. © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. Keywords: constitutive equations; Lode parameter; large strain 1. Introduction The analysis of damage evolution in front of the crack in a machine or structural member requires numerical analysis and the assumption of finite strains. In typical ferritic steels the large deformations precede final failure both according to ductile or cleavage fracture mechanism. To analyze the evolution of this processes in terms of the mechanical field parameters like: the opening stress tensor component, accumulated effective plastic strain, stress triaxiality factor or Lode angle, a very careful calibration of the uniaxial true stress - logarithmic strain (TS-LS) relationship is necessary. Typical extrapolation of the uniaxial tensile curve beyond engineering stress maximum, after either approximation of the "plastic" part of the curve by power or l near function reveals the nature of the mechanical fields in front of the crack. Both the triaxiality parameter ƞ = , or Lode factor L change in front of the ECF22 - Loading and Environmental effects on Structural Integrity Calibration of constitutive equations for the stress level estimation in domain with the large strains Andrzej Neimitz a,* , Ihor Dzioba a , Sebastian Lipiec a a Kielce University of Technology, Al.1000-lecia P.P.7, 25-314 Kielce, Poland Abstract In the paper the calibration technique of the true stress - logarithmic strain curves is proposed, based on the modified Bai Wierzbicki method. Calibration was done using four various speci en geometries selected to provid a wide range of stress triaxialities and Lod parameters. The lev l of plasticity wa controlled by selection of three vari us materials test d at three temperatures: +20 º C, -20 º C, -50 º C. Modification of Bai-Wierzbicki method includes another way of computing the stress triaxiality and Lode parameter, taking into ccount the evolution of these paramet rs during the loading process. Also the m terial softening was includ d before the fin l failure. © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. Keywords: constitutive equations; Lode parameter; large strain 1. Introduction The analysis of damage evolution in front of the crack in a machine or structural member requires numerical analysis and the assu ption of finite strains. In typical ferritic steels the large deformations precede final failure both according to ductile or cleavage fracture mechanism. To analyze the evolution of this processes in terms of the mechanical field parameters like: the opening stress tensor component, accumulated effective plastic strain, stress triaxiality factor r Lode angle, a v ry careful calibration of the uniaxial true stress - logarithmic strain (TS-LS) relationship is n ces ary. Typical extrapolat on of the uniaxial tensile curve beyond engineering stress maximum, after either approximation of the "plastic" part of t e curve by power or linear function reveals the nature of the mechanical fields in front of the crack. Both the triaxiality parameter ƞ = , or Lode factor L change in front f the * Corresponding author. Tel.: +48 41 34-24-307 E-mail address: neimitz@tu.kielce.pl © 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.: +48 41 34-24-307 E-mail address: neimitz@tu.kielce.pl

* Corresponding author. Tel.: +351 218419991. E-mail address: amd@tecnico.ulisboa.pt 2452-3216 © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. 2452-3216 © 2018 The Authors. Published by Elsevier B.V. Peer review under r sponsibility of the ECF22 o ganizers.

2452-3216 © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of PCF 2016.

2452-3216  2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. 10.1016/j.prostr.2018.12.164