PSI - Issue 2_B

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) 2849–2856 Available online at www.sciencedirect.com Structural Integrity Procedia 0 (2016) 000–000 Available online at www.sciencedirect.com Structural Integrity Procedia 00 (2016) 000–000 0

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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.2016.06.356 ∗ Corresponding author. Tel.: + 34-91-336-5244 ; fax: + 34-91-336-6680. E-mail address: beatriz.sanz@upm.es 2452-3216 c 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ECF21. Cracking of the cover might ccur when structures su ff er corrosion of the reinforcement, due to the generation of an oxide layer that occupies a volume greater than that of steel (Andrade et al., 1993; Tuutti, 1982). To simulate that e ff ect and to predict the degree of safety of a ff ected structures, it is essential to model the fracture behavior of concrete an the oxide expansion. For the concrete, models an experimental methods are available to describe its cracking and to determine the parameters defining it, as the method proposed by Planas et al. (2007), which combines the results of stable three point bending tests on notched beams and brazilian tests to calculate a bilinear softening curve, following the standard cohesi e model introduced by Hillerborg et al. (1976). H wever, for the oxide layer direct experimental characterization is very di ffi cult, since xide evolves with the conditions of the medium (A drade et al., 1996), and indirect analysis arises as the main opti n to obtain i formati from the results of experiments and models. For achieving reliable conclusions from indirect analyses, one of the key aspects is that the measurements used as a reference from experiments are sensitive enough to variations in the model parameters being determined; otherwise the parameters are calculated with a high error. For example, the typical measurement of crack width is barely a ff ected by ∗ Corresponding author. Tel.: + 34-91-336-5244 ; fax: + 34-91-336-6680. E-mail address: beatriz.sanz@upm.es 2452-3216 c 2016 The Authors. Publi hed by Elsevier B.V. e r-review under responsibility of the Scientific Committee of ECF21. e ff t an i t d t c n i n o p eer-review under r ee 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 the influence of the oxide and concrete parameters on the results of accelerated corrosion tests Beatriz Sanz a, ∗ , Jaime Planas a , Jose´ M. Sancho b a Universidad Polite´cnica de Madrid, ETSI Caminos, Canales y Puertos, Profesor Aranguren 3, 28040 Madrid, Spain b Universidad Polite´cnica de Madrid, ETS de Arquitectura, Avda. Juan de Herrera 3, 28040 Madrid, Spain Abstract In this work, a numerical study is presented to analyze the influence of the oxide and concrete parameters on the results of cracking induced by corrosion. The results of two-dimensional models of prisms reinforced with a bar and prisms reinforced with a tube are compared. For the si ulations, a model has been used that re roduces the cohesive fracture of concrete and the expansive behavior of the oxide. As a reference, the results of accelerated corrosion tests of prisms reinforced with a tube equipped with special instruments to measure the deformation of the tube are provided, with good agreement. Di ff erences have been observed between the models with a bar and models with a tube in the sensitivity of the curves of results to variations in the model parameters, which have been crucial for indirect determination of the oxide parameters, as discussed in the paper. c 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ECF21. Keywords: Fi ite element modeling, cohesive crack, re forc d concrete, accelerated corrosion, fracture m chanics 1. Introduction Cracking of the cover might occur when structures su ff er corrosion of the reinforcement, due to the generation of an oxide layer that occupies a volume greater than that of steel (Andrade et al., 1993; Tuutti, 1982). To simulate that e ff ect and to predict the degre of safety of a ff ected structures, it is essential to model the fracture behavior of concrete and the oxide expansion. For the concrete, models and experimental methods are available to describe its cracking and to determine the parameters defining it, as the method proposed by Planas et al. (2007), which combines the results of stable three point bending tests on notched beams and brazilian tests to calculate a bilinear softening curve, following the standard cohesive model introduced by Hillerborg et al. (1976). However, for the oxide layer direct experimental characterization is very di ffi cult, since oxide evolves with the conditions of the medium (Andrade et al., 1996), and indirect analysis arises as the main option to obtain information from the results of experiments and models. For achieving reliable conclusions from indirect analyses, one of the key aspects is that the measurements used as a reference from experiments are sensitive enough to variations in the model parameters being determined; otherwise the parameters are calculated with a high error. For example, the typical measurement of crack width is barely a ff ected by 21st European Conference on Fracture, ECF21, 20-24 June 2016, Catania, Italy Study of the i fluence of th oxide and concrete parameters on the results of accelerated corrosion tests Be triz Sanz a, ∗ , Jaime P anas a , Jose´ M. Sancho b a Universidad Polite´cnica de Madrid, ETSI Caminos, Canales y Puertos, Profesor Aranguren 3, 28040 Madrid, Spain b Universidad Polite´cnica de Madrid, ETS de Arquitectura, Avda. Juan de Herrera 3, 28040 Madrid, Spain Abstract In this work, a numerical study is presented to analyze the influence of the oxide and concrete parameters on the results of cracking induced by corrosion. The results of two-dimensional models of prisms reinforced with a bar and prisms reinforced with a tube are compared. For the simulations, a model has been used that reproduces the cohesive fracture of concrete and the expansive behavior of the oxide. As a reference, the results of accelerated corrosion tests of prisms reinforced with a tube equipped with special instruments to measure the deformation of the tube are provided, with good agreement. Di ff erences have been observed between the models with a bar and models with a tube in the sensitivity of the curves of results to variations in the model parameters, which have been crucial for indirect determination of the oxide parameters, as discussed in the paper. c 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ECF21. Keywords: Finite element modeling, cohesive crack, reinforced concrete, accelerated corrosion, fracture mechanics 1. Introduction c I i c ar o i ff the h K n 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/). P r-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