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 e ff ects on Structural Integrity Phase-Field Modelling of Fracture in Viscoelastic Solids Zhengkun Liu a, ∗ , Julian Roggel a , Daniel Juhre a a Institute of Mechanics, Otto von Guericke University Magdeburg, Universita¨ tsplatz 2, 39106 Magdeburg, Germany Abstract The phase-field modeling has emerged as an extremely powerful numerical method to simulate crack propagation with significant success. The crack is herein modeled by a field variable that distinguishes between fully broken and undamaged material. In the proposed phase-field model for crack propagation in viscoelastic solids, a model with a fracture threshold similar to gradient damage theories is developed which can distinguish between fracture behavior in compression and tension. A viscoelastic material model in the framework of finite deformations is used for rubber-like material response. The full model is implemented in the framework of the FE program FEAP and allows both a monolithic and a staggered scheme for the numerical solution. Within FEAP a parameter study is realized. Finally, a summary of the results is presented and an outlook for improvements of the modeling for fracture in viscoelastic solids is given. c 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. Keywords: Phase-field model; Brittle fracture; Finite strain; Finite elements; Visco lastic m terial 1. Introduction Recently, phase-field approach has been widely used for the simulation of fracture (Ambati et al. (2014)). Phase field method can handle curved crack paths, crack kinking, branching angles and crack-front segmentation in three dimensions without any additional criterion. Phase-field model for fracture can be considered as a special type of gradient-enhanced damage models where the sharp crack is replaced by the so-called phase-field parameter s which can distinguish between the intact material and the fully broken material. As of today only a few studies exist which have been dealing with crack propagation in viscoelastic solids by using phase-field method (Miehe et al. (2015)). In this paper, phase-field modelling of fracture processes in viscoelastic solids is investigated. Therefore, we intro duce the phase-field model for brittle fracture which has been extended to the viscoelastic material behavior at finite deformations. Some numerical experiments are studied. The achieved results demonstrate the ability of proposed the phase-field model for fracture in rate-dependent elastic solids. The multi-field coupled problems are performed by using automatic time step size control algorithms. ECF22 - Loading and Environmental e ff ects on Structural Integrity Phase-Field odelling of Fracture in Viscoelastic Solids Zhengkun Liu a, ∗ , Julian Roggel a , Daniel Juhre a a Institute of Mechanics, Otto von Guericke University Magdeburg, Universita¨ tsplatz 2, 39106 Magdeburg, Germany Abstract The phase-field modeling has emerged as an extremely powerful numerical method to simulate crack propagation with significant success. The crack is herein modeled by a field variable that distinguishes between fully broken and undamaged material. In the proposed phase-field model for crack propagation in viscoelastic solids, a model with a fracture threshold similar to gradient damage theories is developed which can distinguish between fracture behavior in compression and tension. A viscoelastic material model in the framework of finite deformations is used for rubber-like material response. The full model is mplemented in the framework of the FE program FEAP and allows both a monolithic and staggered scheme for the numerical solution. Within FEAP a parameter study is realized. Finally, a summary of the results is presented and an outlook for improvements of the modeling for fracture in viscoelastic solids is given. c 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. Keywords: Phase-field model; Brittle fracture; Finite strain; Finite elements; Viscoelastic material 1. Introduction Recently, phase-field approach has been widely used for the simulation of fracture (Ambati et al. (2014)). Phase field method can handle curved crack paths, crack kinking, branching angles and crack-front segmentation in three dimensions without any additional criterion. Phase-field model for fracture can be considered as a special type of gradient-enhanced damage models where the sharp crack is replaced by the so-called phase-field parameter s which can distinguish between the intact material and the fully broken material. As of today only a few studies exist which have been dealing with crack propagation in viscoelastic solids by using phase-field method (Miehe et al. (2015)). In this paper, phase-field modelling of fracture processes in viscoelastic solids is investigated. Therefore, we intro duce the phase-field model for brittle fracture which has been extended to the viscoelastic material behavior at finite deformations. Some numerical experiments are studied. The achieved results demonstrate the ability of proposed the phase-field model for fracture in rate-dependent elastic solids. The multi-field coupled problems are performed by using automatic time step size control algorithms. © 018 The Authors. Published by Elsevier B.V. P iew under esponsibility 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.

* Corresponding author. Tel.: +351 218419991. E-mail address: amd@tecnico.ulisboa.pt ∗ Corresponding author. Tel.: + 49 391 52918; fax: + 49 391 12439. E-mail address: zhengkun.liu@ovgu.de ∗ Corresponding author. Tel.: + 49 391 52918; fax: + 49 391 12439. E-mail address: zhengkun.liu@ovgu.de

2452-3216 © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of PCF 2016. 2210-7843 c 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. 2210-7843 c 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 responsibility of the ECF22 organizers. 10.1016/j.prostr.2018.12.129