PSI - Issue 2_A

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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 Asymptotic near-field analysis of wedges in anisotropic composite plates using first-order shear deformation theory J. Felger ∗ , W. Becker Technische Universita¨ t Darmstadt, Fachgebiet Strukturmechanik, Franziska-Braun-Straße 7, 64287 Darmstadt, Germany Abstract In the present work, a complex potential approach is proposed in order to study the singular solution behaviour at wedges or sharp notches in fibre-reinforced composite plates using first-o der shear deformat on plate theory. The s ngul rity exponent λ as a measure of the strength of the singularity is calculated for di ff erent notch opening angles and boundary conditions along the notch faces. Furthermore, the influence of the fibre orientation on the singularity exponent is discussed in detail. Asymptotic solutions of the governing system of partial di ff erential equations are derived employing a Lekhnitskii-like formalism using three holomorphic potentials. Choosing the complex potentials according to prescribed boundary conditions finally leads to an eigenvalue problem where the singularity exponents appear as roots of the corresponding characteristic equation. In contrast to the classical Kirchho ff Love plate theory, it is shown that the present approach allows for a distinction between singularities associated to transverse shear forces and to bending moments and that the fibre orientation significantly a ff ects the singularity exponent. The obtained asymptotic near fields are compared to finite element data. The findings are in very good agreement with numerical results and results from literature available for the limit case of isotropic material behaviour. c 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ECF21. Keywords: V-notch, Anisotropic plate, Reissner-Mindlin theory, Singularity analysis, Complex potential method In recent years, fibre-reinforced composite materials have become an important feature in modern structural ap plications. Especially in the context of lightweight design, thin-walled structural composite elements like plates and shells are frequently used. In the presence of highly localised stress concentrations due to corners or sharp notches at which the initiation of failure is prone to occur a detailed structural analysis is necessary in order to ensure a reliable assessment of the load carrying capacity. In the framework of linear elasticity geometrical discontinuities even induce stress singularities. Applying concepts of fracture mechanics the local near-tip field in the vicinity of stress singulari ties is of special interest. Due to the complex geometry of notched structures closed-form solutions are hardly available and numerical methods as the finite element method su ff er from a weak convergence leading to a high numerical ef fort. Therefore, methods of asymptotic analysis can be used very advantageously in order to study the local near-tip 21st European Conference on Fracture, ECF21, 20-24 June 2016, Catania, Italy Asymptotic near-field analysis of wedges in anisotropic composite plates using first-order shear deformation theory J. Felger ∗ , W. Becker Technische Universita¨ t Darmstadt, Fachgebiet Strukturmechanik, Franziska-Braun-Straße 7, 64287 Darmstadt, Germany Abstract In the present work, a complex potential approach is proposed in order to study the singular solution behaviour at wedges or sharp notches in fibre-reinforced composite plates using first-order shear deformation plate theory. The singularity exponent λ as a measure of the strength of the singularity is calculated for di ff erent notch opening angles and boundary conditions along the notch faces. Furthermore, the influence of the fibre orientation on the singularity exponent is discussed in detail. Asymptotic solutions of the governing system of partial di ff erential equations are deriv d employing a L khnitskii-like formalism using three holomorphic potentials. Choosing the complex potentials according to prescribed boundary conditions finally leads to an eigenvalue problem where the singularity exponents appear as roots of the corresponding characteristic equation. In contrast to the classical Kirchho ff Love plate theory, it is shown that the present approach allows for a distinction between singularities associated to transverse shear forces and to bending moments and that the fibre orientation significantly a ff ects the singularity exponent. The obtained asymptotic near fields are compared to finite element data. The findings are in very good agreement with numerical results and results from literature available for the li it case of isotropic material behaviour. c 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ECF21. Keywords: V-notch, Anisotropic plate, Reissner-Mindlin theory, Singularity analysis, Complex potential method 1. Introduction In recent years, fibre-reinforced composite materials have become an important feature in modern structural ap plications. Especially in the context of ligh weight design, thin-walled structural composite ele ents like plates and shells are frequently used. In the presence of highly localised stress concentrations due to corners or sharp notches at which the initiation of failure is prone to occur a detailed structural analysis is necessary in order to ensure a reliable assessment of the load carrying capacity. In the framework of linear elasticity geometrical discontinuities even induce stress singularities. Applying concepts of fracture echanics the local near-tip field in the vicinity of stress singulari ties is of special interest. Due to the complex geometry of notched structures closed-form solutions are hardly available and numerical methods as the finite element method su ff er from a weak convergence leading to a high numerical ef fort. Therefore, methods of asymptotic analysis can be used very advantageously in order to study the local near-tip A g m f e t m h p c d n w a - L n f r r p shells are frequent d. t re nce of high alised r s concentratio a w i i e e a i s e g l t l a Copyright © 2016 The Aut ors. Published by Elsevier B.V. This is an op n access article under the CC BY-NC-ND licens (http:// r ativecommons.org/licenses/by-nc-nd/4.0/). r-review under esponsibility 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. 1. Introduction

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.2016.06.313 ∗ Corresponding author. Tel.: + 49 6151 16-26147 E-mail address: felger@fsm.tu-darmstadt.de 2452-3216 c 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ECF21. ∗ Corresponding author. Tel.: + 49 6151 16-26147 E-mail address: felger@fsm.tu-darmstadt.de 2452-3216 c 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ECF21. ∗ Co mstadt.de 2 5 mittee o * Corresponding author. Tel.: +351 218419991. E-mail address: amd@tecnico.ulisboa.pt