PSI - Issue 2_A

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 Struc ural Integrity 2 (2016) 1983–199 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2016) 000–000

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. 21st European Conference on Fracture, ECF21, 20-24 June 2016, Catania, Italy A coupled FFM model to interpret fracture toughness values for brittle materials Donato Firrao a , Paolo Matteis a , Alberto Sapora b *, Pietro Cornetti b , Alberto Carpinteri b a Department of Applied Science and Technology, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino, Italy b Department of Structural, Geotechnical and Building Engineering, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino, Italy Abstract Around 1970 quenching AISI 4340 steel from 1200 °C was discovered to lead to much higher fracture toughness, in the as quenched state, than by conventional austenitizing at 870 °C. Further researches have ascertained that the apparent toughness increase is limited to fracture toughness tests, whereas Charpy-V impact tests do not show any betterment due to high temperature austenitizing, in respect to conventional heat-treating. Various explanations of these contradicting results were given on the b sis of the then existing theories. The puzzling phenomenon is here interpreted by means of Finite Fracture Mechanics theories, based on the contemporaneous fulfilment of a stress requirement and the energy balance. © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ECF21. Keywords: HTA steel, CTA steel, notch radius, ustenitic grain size, Finite Fracture Mecha ics 1. Introduction High Temperature Austenitizing (HTA) of steels, i.e. austenitizing at temperatures well above the ܣ ௖ଷ critical point, has been historically consid red detrim ntal since it promotes large austenitic grain growth and in turn the raise of the ductile-to-brittle tra tion temperature, as measured by Charpy-V type specimens, in respect to conventionally austenitized (CTA) steels. Since 1969 in the then USSR and 1972 in the USA, a scientific movement towards the adopti n of HTA was bor , b sed on a spectacular raise of fracture toughness of as-quenched low alloy high strength steels upon increasing the austenitizing temperature (Bashchenko and Mel'nichenko 1969, Zackay et al. p b e 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.: +39-011-0904911; fax:+39-011-0904989. E-mail address: alberto.sapora@polito.it

* Corresponding author. Tel.: +351 218419991. E-mail address: amd@tecnico.ulisboa.pt 2452-3216 © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ECF21.

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.2016.06.249