PSI - Issue 2_A

ScienceDirect Available online at www.sciencedirect.com Av ilable o line at ww.sciencedire t.com ScienceDirect Structural Integrity Procedia 00 (2016) 000 – 000 Procedia Struc ural Integrity 2 (2016) 3782–3783

www.elsevier.com/locate/procedia

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.2016.06.470 As AA2198 is supposed to replace AA2024 in aerostructures designed with the damage tolerance philosophy, the authors in the present work report and compare their tensile mechanical and fracture toughness behavior under different aging conditions to simulate the natural aging parameter. To this end, a comparison of both alloys of their tensile mechanical behavior is reported for different stages of aging, including conditions of under-aging (UA), peak-aging (PA) and over-aging (OA). Typical ABSTRACT Al–Cu–Li–Mg based alloys exhibit an excellent combination of low density, high elastic modulus and high specific strength and have already being used as structural materials for aerospace applications. The mechanical properties of these alloys are often associated with the addition of Li which enables the formation of several strengthening precipitates including δ ′ (Al 3 Li), θ ′ (Al 2 Cu), δ (AlLi) and T 1 (Al 2 CuLi). Other precipitates have also been reported in these alloys that include GP zones, θ (Al 2 Cu), Ω (Al 2 Cu), S ′ (Al 2 CuMg), and β ′ (Al 3 Zr), e.g. [1-3]. Nevertheless, the quasi-static mechanical properties of AA2198 are scarcely reported in the open literature while quite few for the fracture toughness. For example, Chen et al. [4] performed tests on two different heat treated AA2198 (namely T351 and T851) and investigated their plastic and fracture behavior. Steglich et al. [5, 6] investigated experimentally and analytically the anisotropic deformation of AA2198-T8 occurred during mechanical loading with and without th presence of artificial notches. In a recent publication [7], a combination of transmission electron microscopy, atom probe tomography and high-energy X-ray diffraction was employed to investigate the influe c of local microstructural changes strengthening in AA2198 in different aging conditions. As AA2198 is supposed to replace AA2024 in aerostructures designed with the damage tolerance philosophy, the authors in the present work report and compare their tensile mechanical and fracture toughness behavior under different aging conditions to simulate the natural aging parameter. To this end, a comparison of both alloys of their tensile mechanical behavior is reported for different stages of aging, including conditions of under-aging (UA), peak-aging (PA) and over-aging (OA). Typical 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. Effect of artificial aging on the mechanical performance of (Al-Cu) 2024 and (Al-Cu-Li) 2198 aluminum alloys Nikolaos D. Alexopoulos 1(*) , Aggeliki Proiou 1 , Theano Examilioti 1 , Nikolai Kashaev 2 , Stefan Riekehr 2 and Stavros K. Kourkoulis 3 1 University of the Aegean, Department of Financial Engineering, Chios, Greece 2 Helmholtz-Zentrum Geesthacht, Institute of Materials Research, aterials Mechanics, Geesthacht, Germany 3 National Technological University of Athens, Department of Applied Mathematical and Physical Sciences Division of Engineering, Laboratory of Strength and Materials, Zografou, Athens, Greece (*) Email: alexop@aegean.gr ABSTRACT Al–Cu–Li–Mg based alloys exhibit an excellent combination of low density, high elastic modulus and high spec fic strength and have already being used s str ctural materials for aerospace applications. The mechanical properties of these alloys are often associated with the addition of Li which enables the formation several strengthening precipitates including δ ′ (Al 3 Li), θ ′ (Al 2 Cu), δ (AlLi) and T 1 (Al 2 CuLi). Other precipitates have also been reported in these alloys that include GP zones, θ (Al 2 Cu), Ω (Al 2 Cu), S ′ (Al 2 CuMg), and β ′ (Al 3 Zr), e.g. [1-3]. Neverthele s, the quasi-static mechanical properties of AA2198 are scarcely reported in the open literature while quite few for the fracture toughness. For example, Chen et al. [4] performed tests on two different heat treated AA2198 (namely T351 and T851) and investigated their plastic and fracture behavior. Steglich et al. [5, 6] investigated experimentally and analytically the anisotropic def rmation of AA2198-T8 occurred during mechanical loading with and without the presence of artificial notches. In a recent publication [7], a combination of transmission electron microscopy, atom probe tomography and high-energy X-ray diffraction was employed to investigate the influence of local microstructural changes on strengthening in AA2198 in different aging conditions. Effect of artificial aging on the mechanical performance of (Al-Cu) 2024 and (Al-Cu-Li) 2198 aluminum alloys Nikolaos D. Alexopoulos 1(*) , Aggeliki Proiou 1 , Theano Examilioti 1 , Nikolai Kashaev 2 , Stefan Riekehr 2 and Stavros K. Kourkoulis 3 1 University of the Aegean, Department of Financial Engineering, Chios, Greece 2 Helmholtz-Zentrum Geesthacht, Institute of Materials Research, Materials Mechanics, Geesthacht, Germany 3 National Tech ological University of Athens, Department of Applied Mathematical and Physical Sciences Division of Engineering, Laboratory of Strength and Materials, Zografou, Athens, Greece (*) Email: nalexop@aegean.gr 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. © 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