PSI - Issue 3

ScienceDirect Available online at www.sciencedirect.com Available o line at www.sciencedire t.com ScienceDirect Structural Integrity Procedia 00 (2016) 000 – 000 Procedia Structu al Integrity 3 (2017) 468–476 Structural Integrity Procedia 00 (2017) 000–000 Av ilable online at ww.sci nce ir t. Structural Integrity Procedia 00 (2017) 000–000 Structural Integrity Procedia 00 (2017) 000–000 Available online at www.sciencedirect.com Structural Integrity Procedia 00 (2017) 000–000 Available online at www.sciencedirect.com il l li t . i ir t.

www.elsevier.com/locate/procedia www.elsevier.com / locate / procedia www.elsevier.co / locate / procedia .elsevier.co / locate / procedia www.elsevier.com / locate / procedia

2452-3216 © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of PCF 2016. Copyright © 2017 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 IGF Ex-Co. 10.1016/j.prostr.2017.04.063 2452-3216 © 2017 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of IGF Ex-Co. ∗ Corresponding author. Tel.: + 39-0521-905927 ; fax: + 39-0521-905924. E-mail address: spagnoli@unipr.it 2452-3216 2017 The Authors. Published by Elsevier B.V. Peer-review und r responsibility of the Scientific Committee of IGF Ex-Co. 2452-3216 2017 he uthors. ublished by lsevier . eer-review under responsibility of the Scientific Committee of IGF Ex-Co. ∗ Corresponding author. Tel.: + 39-0521-905927 ; fax: + 39-0521-905924. E-mail address: spagnoli@unipr.it 2452-3216 © 2017 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of IGF Ex-Co. * Corresponding author. Tel.: +351 218419991. E-mail address: amd@tecnico.ulisboa.pt ∗ or esponding author. Tel.: + 39-0521-905 27 ; fax: + 39-0521-905924. E-mail address: sp gnoli@u pr.it ∗ orresponding author. el.: 39-0521-905927 ; fax: 39-0521-905924. - ail address: spagnoli@unipr.it Let us consider a large plate with a single centred cut of length 2 a . A cartesian coordinate system x , y is introduced in the centre of the plate so that the cut covers the region | x | ≤ a , y = 0. An elliptic wedge with major and minor Let us consider a large plate with a single centred cut of length 2 a . A cartesian coordinate system x , y is introduced in the centre of the plate so that the cut covers the region | x | ≤ a , y = 0. An elliptic wedge with major and minor t s si r l r l t it si l tre t f l t . rt si r i t s st , is i tr i t tr f t l t s t t t t rs t r i | | , = . lli ti it j r i r Let us consider a large plate with a single centred cut of length 2 a . A cartesian coordinate system x , y is introduced in the centre of the plate so that the cut covers the region | x | ≤ a , y = 0. An elliptic wedge with major and minor 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. Copyright © 2017 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 IGF Ex-Co. XXIV Italian Group of Fracture Conference, 1-3 March 2017, Urbino, Italy On the fracture processes of cutting P. Ståhle a , A. Spagnoli b, ∗ , M. Terzano b a Division of Solid Mechanics, Lund University, SE-221 00 Lund, Sweden b Department of Engineering and Architecture, University of Parma, Viale Usberti 181 / A, 43124 Parma, Italy Abstract The process of cutting is treated as a fracture mechanical process. For an elliptic rigid wedge pressed into an elastic material, fracture may occur as an autonomous process if the tip of the wedge is su ffi ciently blunt or is a ff ected by the geometry of the wedge if the tip is sharp. The conditions leading to the former or the latter case is obtained as a relation between the wedge tip radius, the fracture toughness and the modulus of elasticity. These limits and the intermediate states are discussed. The implications of the drastic changes of the mechanical state of the near tip regi n when the wedge edge is sharp are also discussed. © 2017 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of IGF Ex-Co. Keywords: Cutting; fracture processes; linear elastic; fracture toughness. 1. Introducti n The mechanics of cutting has been attracting much attention in the literature, with the aim of addressing di ff erent technical problems (Williams and Patel, 2016; Williams et al., 2016) ranging from metal machining (Williams, 1998; Williams et al., 2010), to cutting of soft solids, such as biological tissues, foodstu ff s or elastomeric materials (Goh et al., 2005; McCarthy et al., 2007, 2010). Cutting is al o used as an experim nt l method for determining fracture toughness of polymers (Patel et al., 2009). Typically, cutting process is characterized by an indentation stage followed by a stage where the target material undergoes a progressive separation. The mechanical response in both stages is governed by the cutting tool shape (blade), the target material and the cutting rate. In the present paper, the quasi-static fracture stage is studied by means of a simple model which can be handled analytically, where the blade is modelled as a rigid wedge inserted into an elastic plate. XXIV Italian Group of Fracture Conference, 1-3 March 2017, Urbino, Italy On the fracture processes of cutting P. Ståhle a , A. Spagnoli b, ∗ , M. Terzano b a Division of Solid Mechanics, Lund University, SE-221 00 Lund, Sweden b Department of Engineering and Architecture, University of Parma, Viale Usberti 181 / A, 43124 Parma, Italy Abstract The process of cutting is treated as a fracture mechanical process. For an elliptic rigid wedge pressed nto an elastic material, fracture may occur as an autonomous process if the tip of the wedge is su ffi ciently blunt or is a ff ected by the geometry of the wedge if the tip is sharp. The conditions leading to the former or the latter case is obtained as a relation between the wedge tip radius, the fracture toughness and the modulus of elasticity. These limits and the intermediate states are discussed. The implications of the drastic changes of the mechanical state of the near tip region when the wedge edge is sharp are also discussed. © 2017 The Authors. Published by Elsevier B.V. P er-review under responsibility of the Scientific Committee of IGF Ex-Co. Keywords: Cutting; fracture processes; linear elastic; fracture toughness. 1. Introduction The mec anics of cuttin has been attracting much attention in the literature, with th aim of addressing di ff erent technical problems (Williams and Patel, 2016; Williams et al., 2016) ranging from metal machining (Williams, 1998; Williams et al., 2010), to cutting of soft solids, such as biological tissues, foodstu ff s or elastomeric materials (Goh et al., 2005; McCarthy et al., 2007, 2010). Cutting is also used as an experimental method for determining fracture toughness of polymers (Patel et al., 2009). Typically, cutting process is characterized by an indentation stage followed by a stage where the target material undergoes a progressive separation. The mechanical response in both stages is governed by the cutting tool shape (blade), the target material and the cutting rate. In the present paper, the quasi-static fracture stage is studi d by means of a simple mod l which can be handled analytically, where the blade is modelled as a rigid wedge inserted into an elastic plate. XXIV Italian Group of Fracture Conference, 1-3 March 2017, Urbino, Italy . t l a , . li , , . Terzano b a ivision of Solid echanics, und niversity, S -221 00 u d, S eden b epart ent of ngineering and Architecture, niversity of ar a, iale sberti 181 / A, 43124 Parma, Italy str ct T e r cess f c tti is treate as a fract re ec a ical r cess. r a elli tic ri i e e resse i t a elastic aterial, fract re a ccur as an autonomous process if the tip of the wedge is su ciently blunt or is a ected by the geometry of the wedge if the tip is s ar . e co iti s leading to the former r t e latter case is btaine as a relation betwee t e e e ti ra ius, t e fract re t ness and the modulus of elasticity. These limits and th intermediate st tes are di cussed. The i licati s f t e rastic c a es f t e mechanical state f t e ear ti re i whe t e e e e e is s ar are als isc sse . e t rs. lis e lse ier . . Peer-review under responsibility of the Scientific Committee of IGF Ex-Co. Key r s: utting; fracture processes; linear elastic; fracture toughness. . I t tio ha i s f tti s ttr ti tt ti i t lit r t r , it t i f r ssi i ff r t t i l r l s ( illi s t l, ; illi s t l., ) r i fr t l i ing ( illi s, 8; Willi s t ., ), t tti f s ft s li s, s s i l i l t ss s, f st ff r l st ri t ri ls ( t l., ; rt t l., , ). tti is l s s ri t l t f r t r i i r t r t ss f l ers ( t l t l., ). i ll , tti r ss is r t ri i t ti st f ll st r t t r t t ri l r s r r ssi s r ti . i l r s s i t st s is go r t tti t l s ( l ), t t r t t ri l t tti r t . In the present paper, t si-st ti fr t r st is st i s f si l del i l l ti ll , r t l is ll s ri i i s rt i t l sti l t . XXIV Italian Group of Fracture Conference, 1-3 March 2017, Urbino, Italy On the fracture processes of cutting P. Ståhle a , A. Spagnoli b, ∗ , M. Terzano b a Division of Solid Mechanics, Lund University, SE-221 00 Lund, Sweden b Department of Engineering and Architecture, University of Parma, Viale Usberti 181 / A, 43124 Parma, Italy Abstract The process of tting is treated as a fracture mechanical process. For an elliptic rigid wedge pressed into an elastic material, fracture may occur as an auton mous process if the tip f the wedge is su ffi ciently blu t or is a ff ected by the geometry of the wedge if the tip is sharp. The conditions leading to the former or the latter case is obtained as a relation between the wedge tip radius, the fra ture toughness and the modulus of elasticity. These limits and the int rmediate states are discussed. The implications of the drastic changes of the mechanical stat of the near tip r gion when the w dge edge is sharp are also discussed. © 2017 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scie tific Committee of IGF Ex-Co. Keywords: Cutting; fracture processes; linear elastic; fracture toughness. 1. Introduction The mechanics of cutting has been attracting much attention in the literature, with the aim of addressing di ff erent technical problems (Williams and Patel, 2016; Williams et al., 2016) ranging from metal machining (Williams, 1998; Williams et al., 2010), to cutting of soft solids, such as biological tissues, foodstu ff s or elastomeric materials (Goh et al., 2005; McCarthy et al., 2007, 2010). Cutting is also used as an experimental method for determining fracture toughness of polymers (Patel et al., 2009). Typically, cutting process is characterized by an indentation stage followed by a stage where the target material undergoes a progressive separation. The mechanical response in both stages is governed by the cutting tool shape (blade), the target material and the cutting rate. In the present paper, the quasi-static fracture stage is studied by means of a simple model which can be handled analytically, where the blade is modelled as a rigid wedge inserted into an elastic plate. © 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. 2. The wedge model for the cutting tool 2. The wedge model for the cutting tool . l f t tti t l 2. The wedge model for the cutting tool