PSI - Issue 13

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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 Ductile fracture of advanced pipeline steels: study of stress states and energies in dynamic impact specimens - CVN and DWTT Letícia dos Santos Pereira a , Rodrygo Figueiredo Moço a , Gustavo Henrique Bolognesi Donato a* a Centro Universitário FEI, Humberto de A. Castelo Branco Av., 3972, São Bernardo do Campo, 09850-901, Brazil Abstract The development of robust protocols for assessing the structural inte rity of gas pipelines is of paramount relevance, since failures can lead to financial and human losses. In this scenario, the material’s ability to slow down the propagation of a running crack (crack arrest) becomes a design requirement. Several empirical models and criteria, calibrated by real pipeline burst tests, have been developed, being the Battele Two Curve Method (BTCM) one example of technique widely employed during decades. With the evolution of steels, there was a significant increase of ductility and toughness, in a way that such semi-empirical models usually based on the energy absorbed in the Charpy impact test (ISO 148-1, ASTM E-23) began to present unsatisfactory predictions. This may be explained by the fact that in current high-ductility and high-toughness materials (e.g.: API-5L X65, X80, X100), the dominant mechanism of fracture propagation is plastic collapse. Consequently, the energies involved in deforming and fracturing a laboratory specimen are remarkably altered and transferability to pipelines by means of the aforementioned models can be lost. Therefore, for a better phenomenological comprehension of the ductile fracture process under such circumstances, this work investigates Charpy and DWTT (ASTM E-436) dynamic tests assessing stress fields and respective energies involved in deformation and fracture. It is of great interest to evaluate the energy associated to steady state ductile fracture and thus try to characterize the energy available to slow down an ongoing fracture. Pipelines are references for the developments and support assumptions and some conclusions. Based on these golas, numerical analyses including damage models (XFEM and GTN) were implemented, including parameters’ calibration and sensitivity analyses. The methodology closely reproduced available experimental results. Besides that, stress fields and energies could be quantified for the studied geometries and such analyses indicated the potential and limitations of Charpy and DWTT specimens to characterize the energies required to describe steady state ductile crack propagation and crack arrestability. Results support further developments related to pipeline integrity assessments. © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. © 2018 The Authors. Published by Elsevier B.V. Peer-revi w under respon ibility of the ECF22 organizers. ECF22 - Loading and Environmental effects on Structural Integrity Ductile fracture of advanced pipeline steels: study of stress states and energies in dynamic impact specimens - CVN and DWTT Letícia dos Santos Pereira a , Rodrygo Figueiredo Moço a , Gustavo Henrique Bolognesi Donato a* a Centro Universitário FEI, Humberto de A. Castelo Branco Av., 3972, São Bernardo do Campo, 09850-901, Brazil Abstract The development of robust protocols for assessing the structural integrity of gas pipelines is of paramount relevance, since failures can lead t financial and human losses. In this scenario, the material’s ability to slow down the pr pagation of a ru ning crack (crack arrest) becomes a design requirement. Sev ral empirical models and criteria, calibrated by real pipeline burst tests, h ve been developed, being the Battele Two Curve Method (BTCM) one example of t chnique widely employed during decade . With the evolution of steels, there was a significant increase of ductility and toughness, in a way that such semi-empirical models usually bas d n the energy absorb d in the Charpy impact test (ISO 148-1, ASTM E-23) began to present unsatisfactory predictions. This may be explained by the fact that in current high-ductility and high-toughness materials (e.g.: API-5L X65, X80, X100), the dominant mechanism of fracture propagatio is plastic collapse. Consequently, the en rgies involved in deforming and fracturing a laboratory specimen are remarkably altered and transferability to pipelines by mea s of the af reme tioned odels can be lost. Therefore, for a better phenomenological comprehe sion of the ductile fracture process under such circumstances, this w rk investigates Charpy and DWTT (ASTM E-436) dynamic tests assessing stress fields a d respective energies involved in deformation and fracture. It is of great interest to evaluate the energy associated to steady state ductile fracture and thus try to characterize the energy available to slow down an ongoing fracture. Pipelines are references for the d velopm nts and upport assu ptions and some conclusions. Based on these golas, numerical analyses including damage models (XFEM and GTN) were implemented, including parameters’ calibration and sensitivity analyses. The methodology closely reproduced availabl experimental results. Besides that, stress fields and energies could be quantified for the studied geometries and such analyses indicated the potential and limit tions of Charpy and DWTT specimens to characterize the energies requir d to describe steady state ductil crack propagation and crack arrestability. Results support further developments related to pipeline integrit assessments. © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. © 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. Keywords: Gas pipelines; Crack arrest; Advanced steels; Damage models; Energy assessment. Keywords: Gas pipelines; Crack arrest; Advanced steels; Damage models; Energy assessment.

Nomenclature D Nomenclature D

XFEM damage parameter crack size variation XFEM damage parameter crack size variation

da da

* 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. 2452-3216 © 2018 The Authors. Published by Elsevier B.V. Peer-review under r sponsibility of the ECF22 organizers.

2452-3216 © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of PCF 2016.

2452-3216  2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. 10.1016/j.prostr.2018.12.219