PSI - Issue 2_B

ScienceDirect Available online at www.sciencedirect.com Av ilable o line at ww.sciencedire t.com cienceDirect Structural Integrity Procedia 00 (2016) 000 – 000 Procedia Struc ural Integrity 2 (2016) 1133–1142 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2016) 000–000 Available online at www.sciencedirect.com Sci nceDire t 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 Very High Cycle Fatigue Resistance of the Low Alloyed Steel 42CrMo4 in Medium- and High-Strength Quenched and Tempered Condition K.-H. Lang a, * , M. Korn a and T. Rohm a, b a Karlsruhe Institute of Technology (KIT) – Institute for Applied Materials (IAM), Engelbert-Arnold-Str. 4, 76128 Karl ruhe, Germany b University of Applied Science, Moltkestr. 30, 76133 Karlsruhe, Germany Abstract Low cyclical loadings can cause failure after a very high number of cycles in the so-called “Very High Cycle Fatigue” (VHCF) area. Thereby, failure initiates typically below the surface at defects like non-metallic inclusions. The appearance of VHCF failure depends o the microstructure of the material and the loading situation. E.g., a quenched and tempered steel with a given dist ibution of non-metallic inclusions may be insensitive to VHCF failure in a low strength condition but very s nsitive in a high-strength condition. Th present study inv s igates the influence of tempering temperature on the fatigue resistance of a low alloyed steel. Uniaxial tension-compression fatigue tests (50 Hz/1 kHz and R=-1) were performed on specimens made of 42CrMo4, which were tempered at six different temperatures to produce wide a range of ultimate strength. With the decrease in tempering temperature the sensitivity of subsurface crack initiation at inner defects increases. High tempered conditions with R m < 1400 MPa show no failure between 10 6 and 10 9 cycles. Crack initiation almost occurs at the surface as a result of local plasticity and surface defects. The fatigue resistance at 10 9 cycles (R w/9 ) matches to the fatigue resistance at 10 6 cycles (R w/6 ). The low tempered conditions show a tendency of increasing life scatter and the threshold value for subsurface crack initiation increase with decreasing strength-level. The study indicated that for high-strength heat treatment condition the diff renc betwee he fatigue strength at 10 6 and 10 9 increases with decreasing tempering temperature. A functional relationship between these two fatigue strength was found and verified experimentally. It seems that the stress intensity factor K which arises as a function of local loading conditions at inner stress-raisers depends on the yielding /hardening properties of the material around them. 21st European Conference on Fracture, ECF21, 20-24 June 2016, Catania, Italy V ry High Cycle Fatigue Resistance of the Low Alloyed Steel 42CrMo4 in Medium- and High-Strength Qu nched and Tempered Condition K.-H. Lang a, * , M. Kor a and T. Rohm a, b a Karlsruhe Institute of Technology (KIT) – Institute for Applied Materials (IAM), Engelbert-Arnold-Str. 4, 76128 Karlsruhe, Germany b University of Appl ed Science, Moltkestr. 30, 76133 Karlsruhe, Germany Abstract Low cyclical loadings can cause failure after a very high number of cycles in the so-called “Very High Cycle Fatigue” (VHCF) area. Thereby, failure initiates typically below the surface at defects like non-metallic inclusions. The appearance of VHCF failure depends on the microstructure of the material and the loading situation. E.g., a quenched and tempered steel with a given distributio of non-m tallic inclusio s may be i sensitive to VHCF failur n a low strength condition but very sensitive in a high-strength condition. The present s udy investigat s the influence of tempering temperature on the fatigue resistance of a low alloyed steel. Uniaxial tension-compression fatigue tests (50 Hz/1 kHz and R=-1) were performed on specimens made of 42CrMo4, which were tempered at six different temperatures to produce wide a range of ultimate strength. With the decrease in tempering temperature the sensitivity of subsurface crack initiation at inner defects increases. High tempered conditions with R m < 1400 MPa show no failure between 10 6 and 10 9 cycles. Crack initiation almost occurs at the surface as a result of local plasticity and surface defects. The fatigue resistance at 10 9 cycles (R w/9 ) matches to the fatigue resistance at 10 6 cycles (R w/6 ). Th low tempered conditions show a t ndency of increasing life scatter and the threshold value for subsurface crack initiation increase with decreasing strength-level. The study indicated that for high-strength heat treatment conditions the d ff rence between the fatigue strength at 10 6 and 10 9 increases with decreasing tempering temp rature. A functional re ations ip between these two fatigue strength was found and verified experimentally. It seems that the stress intensity factor K which arises as a function of local loading conditions at inner stress-raisers depends on the yielding /hardening properties of the material around the . 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.: +49-721-60842605; fax: +49-721-60848044. E-mail address: karl-heinz.lang@kit.edu

* Corresponding author. Tel.: +351 218419991. E-mail address: amd@tecnico.ulisboa.pt * Corresponding author. Tel.: +49-721-60842605; fax: +49-721-60848044. E-mail address: karl-heinz.lang@kit.edu 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.2016.06.145 2452-3216 © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ECF21.