PSI - Issue 13

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 Structu al Integrity 13 (2018) 123–130 Available online at www.sciencedirect.com Structural Integrity Procedia 0 (2018) 000–000 Av ilable online at ww.sciencedir t.c Structural Integrity Procedia 00 (2018) 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. ECF22 - Loading and Environmental effects on Structural Integrity Testing of Brazilian Disk Specimens With a Delamination Between a Transversely Isotropic and a Tetragonal Composite Ply Mor Mega ∗ , Leslie Banks-Sills The Dreszer Fracture Mechanics Laboratory , School of Mechanical Engineering, Tel Aviv University, 69978 Ramat Aviv, Israel Abstract Fracture toughness tests using the Brazilian disk specimen (BD) were carried out to determine the toughness properties of a delamination between two fiber reinforced composite plies. The upper ply is a transversely isotropic UD fabric with fibers oriented in the 0 ◦ -direction and the lower ply is a tetragonal plain balanced weave with fibers oriented in the + 45 ◦ / − 45 ◦ -directions. The composite is manufactured as a wet-layup. With the BD specimen, mixed mode combinations are achieved by changing the loading angle ω , between the load line and the delamination. Eight specimens were tested at four loading angles, two for each angle. Based on the test results, finite element (FE) analyses were carried out in conjunction with two methods, the three-dimensional conservative M -integral and displacement extrapolation (DE) to obtain the stress intensity factors along the delamination front for each specimen resulting from mechanical loads, as well as residual stresses. The two methods were used in order to validate the results. Both methods were extended for this specific interface and made use of the first term of the asymptotic solution of the displacement field. The stress intensity factors were superposed, and the critical interface energy release rates and phase angles were calculated and plotted. c ⃝ 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ECF22. Keywords: Delamination; Fracture toughness; Interface energy release rate; Multidirectional composite; Stress intensity factors The fracture toughness characterization of composite materials is necessary to determine the load-bearing capac ity of structures, improve design considerations, and avoid catastrophic failures. Fiber reinforced polymer laminate composites have emerged as important structural engineering materials as a result of their many advantages such as high sti ff ness to weight ratio or high strength to weight ratio [1]. However, it has been observed that laminates have poor resistance to delamination, or ply separation, which may result in catastrophic failure of the composite structure [2, 3]. The properties of fiber reinforced composites may be tailored to a specific application. These properties are strongly influenced by the fiber orientation and fiber volume fraction of the composite [4]. In order to manufacture a composite © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. ECF22 - Loading and Environmental effects on Structural Integrity Testing of razilian isk Speci ens ith a ela ination et een a Transversely Isotropic and a Tetragonal o posite Ply or ega ∗ , Leslie Banks-Sills The Dreszer Fracture Mechanics Laboratory , School of Mechanical Engineering, Tel Aviv University, 69978 Ramat Aviv, Israel Abstract Fracture toughness tests using the Brazilian disk specimen (BD) were carried out to determine the toughness properties of a delamination between two fiber reinforced composite plies. The upper ply is a transversely isotropic UD fabric with fibers oriented in the 0 ◦ -direction and the lower ply is a tetragonal plain balanced weave with fibers oriented in the + 45 ◦ / − 45 ◦ -directions. The composite is manufactured as a wet-layup. With the BD specimen, mixed mode combinations are achieved by changing the loading angle ω , between the load line and the delamination. Eight specimens were tested at four loading angles, two for each angle. Based on the test results, finite element (FE) analyses were carried out in conjunction with two methods, the three-dimensional conservative M -integral and displacement extrapolation (DE) to obtain the stress intensity factors along the delamination front for each specimen resulting from mechanical loads, as well as residual stresses. The two methods were used in order to validate the results. Both methods were extended for this specific interface and made use of the first term of the asymptotic solution of the displacement field. The stress intensity factors were superposed, and the critical interface energy release rates and phase angles were calculated and plotted. c ⃝ 018 The Authors. Published by Elsevier B.V. P r ie unde responsibility of the Scientific Committee of ECF22. Keywords: Delamination; Fracture toughness; Interface energy release rate; Multidirectional composite; Stress intensity factors 1. Introduction The fracture toughness characterization of composite materials is necessary to determine the load-bearing capac ity of structures, improve design considerations, and avoid catastrophic failures. Fiber reinforced polymer laminate composites have emerged as important structural engineering materials as a result of their many advantages such as high sti ff ness to weight ratio or high strength to weight ratio [1]. However, it has been observed that laminates have poor resistance to delamination, or ply separation, which may result in catastrophic failure of the composite structure [2, 3]. The properties of fiber reinforced composites may be tailored to a specific application. These properties are strongly influenced by the fiber orientation and fiber volume fraction of the composite [4]. In order to manufacture a composite © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of PCF 2016. 1. Introduction Keywords: High Pressure Turbine Blade; Creep; Finite Element Method; 3D Model; Simulation.

2452-3216 © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of PCF 2016. ∗ Corresponding author. Tel.: + 972-3-640-8992 ; fax: + 972-3-640-8992. E-mail address: pellegmor@gmail.com 2452-3216 c ⃝ 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ECF22. ∗ Corresponding author. Tel.: + 972-3-640-8992 ; fax: + 972-3-640-8992. E-mail address: pellegmor@gmail.com 2452-3216 c ⃝ 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ECF22. * 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. 10.1016/j.prostr.2018.12.021