PSI - Issue 2_B

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) 3256–3263 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2016) 000–000 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2016) 000–000

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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. 21st European Conference on Fracture, ECF21, 20-24 June 2016, Catania, Italy Study of th contribution of diff rent effects induced by the punching process on the high cycle fatigue strength of the M330-35A electrical steel Helmi Dehmani a,b,c * Charles Brugger b , Thierry Palin-Luc b , Charles Mareau c , Samuel Koechlin a a Leroy Somer, Boulevard Marcellin Leroy 16915 Angoulème, France b Arts et Métiers ParisTech, I2M, CNRS, Esplanade des Arts et Métiers, 33405 Talence – France c Arts et Métiers ParisTech, LAMPA, 2 boulevard du Ronceray, 49035 Angers – France Abstract Because of their improved magnetic properties, Fe-Si alloys are widely used for new electric motor generations. The use of punching process to obtain these components specially affects their mechanical behavior and fatigue strength. This work aims at studying the influence of punching operations on the fatigue behavior of a Fe-Si alloy. High cycle fatigue tests are performed on different smooth specimen configurations with either punched or polished edges. Results show a significant decrease of the fatigue strength for punched specimens compared to polished ones. To understand the origin of the fatigue failure on punched specimens, SEM observations of the fracture surfaces are carried out. They reveal that crack initiation always occurs on a punch defect. Additional xperimental techniques are combined to characterize how the edges are altered by pu ching. The impact f punching operations on residual stresses and hardening is then investigated. Residual stresses are quantified on punche edges using X-ray diffraction techniques. Important tensile residual stresses exist in the loading direction as a result of punching operations. Also, according to XRD analyses and micro-hardness measurements, the hardened zone depth is about 200 µm. To dissociate the respective influences of strain hardening, residual stresses and geometrical defects, a heat treatment is applied to both punched and polished specimens in order to quantify the contribution of each parameter to the high cycle fatigue resistance. Results show that the geometry of defects is one of the most influent parameters. Consequently, a finite element model is developed to simulate the influence of edge defects on the fatigue strength of punched components. A non-local high cycle fatigue criterion is finally used as post-processing of FEA to consider the effect of defects and the associated stress-strain gradients in the HCF strength assessment. © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ECF21. 21st European Conference on Fracture, ECF21, 20-24 June 2016, Catania, Italy Study of the contribution of different effects induced by the punching process on the high cycle fatigue strength of the M330-35A electrical steel Helmi Deh ani a,b,c * Charles Brugger b , Thierry Palin-Luc b , Charles Mareau c , Samuel Koechlin a a Leroy Somer, Boulevard Marcellin Leroy 16915 Angoulème, France b Arts et Métiers ParisTech, I2M, CNRS, Esplanade des Arts et Métiers, 33405 Talence – France c Arts et Métiers ParisTech, LAMPA, 2 boulevard du Ronceray, 49035 Angers – France Abstract Because of their improved magnetic properties, Fe-Si alloys are widely used for new electric motor generations. The use of pun hing proc ss to obtain these components specially affect th ir mechanical behavior and fatigue st ength. This work aims at st dying the influence of punching operations on the fatigue be avior of Fe-Si alloy. High cycle fatigue tests are performed on differe t smooth specimen confi urations with either punched or polished edges. Results show significant decrease of the fatigu strength for punched specimens compared to polished ones. To un erstand th origin f the fatigue failure on punched specimens, SEM bservation of the fracture surfaces are carried out. They r ve l that crack initia ion lways occurs on a punch defect. Additional experime tal techniques are combined to characterize how the edges re altered by punching. The impact of punchi op rati ns on residual stresses and hard ning is then inv stigat d. Residual tresses a quant fied on pu ched edges usi g X-ra diffracti t chniques. Important tensile re idual stres es exist in the loading di ection as a result of punching operations. Also, c rding to XRD analyses and micro-hardne s mea urements, t h r ene zone depth is about 200 µm. To dissoc ate the respective influences of strain h rdening, resi ual tresses and geometrical defects, a h at treatment is applied t both punched and pol shed sp cimens in order to qua tify the contribution of each pa ameter to he high cycle fatigue resistance. Results show that the g ometry of defects is one of the most infl ent parameters. Consequently, a finit element model is d ve oped to simulat the influence of edge defects on the fa igue strength of punched components. A non-local high cycle fatigue criterion is finally used as p st-processing of FEA to consider the e fect of efects a d the ass ciated stress-strain gradients n the HCF strength assessmen . © 2016 The Authors. Publis ed by Elsevier B.V. Peer-review under espons bility of the Scientific Committee of ECF21. Copyright © 2016 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativ commons.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: Electrical steel, high cycle fatigue, punching effect, defect, residual stress

Keywords: High Pressure Turbine Blade; Creep; Finite Element Method; 3D Model; Simulation. Keywords: Electrical steel, high cycle fatigue, punching effect, defect, residual stress

* Corresponding author. Tel.: +351 218419991. E-mail address: amd@tecnico.ulisboa.pt 2452-3216 © 2016 The Authors. Published by Elsevier B.V. Peer-review und r responsibility of the Scientific Committee of ECF21. 2452-3216 © 2016 The Authors. Published by Elsevier B.V. Peer review under r sponsibility of the Scientific Committee of ECF21. * Corresponding author. Tel.: +33 5 56 84 53 91; fax: +33 5 56 84 53 66. E-mail address: helmi.dehmani@ensam.eu * Corresponding author. Tel.: +33 5 56 84 53 91; fax: +33 5 56 84 53 66. E-mail address: helmi.dehmani@ensam.eu

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.2016.06.406