PSI - Issue 13

ScienceDirect Available online at www.sciencedirect.com Available o line at ww.sciencedire t.com ienceDirect Structural Integrity Procedia 00 (2016) 000 – 000 Procedia Structural Integrity 13 (2018) 1447–1452 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2018) 000–000 Available online at www.sciencedirect.com ScienceDirect Structural Int grity Procedia 00 (2018) 000–000

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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 Analysis of an as-cast high Si slab to elucidate fundamental causes of the fracture mechanism: Clinking Guy Khosla a , Daniel Balint a , Didier Farrugia b , Matthew Hole a , Catrin M. Davies a a Department of Mechanical Engineering, Imperial College London, South Kensington Campus, London, UK, SW7 2AZ b TATA Steel UK, Research & Development, Swinden Technology Centre, Rotherham, S60 3AR Abstract ‘Clinking’ refers to the fast and loud transverse fracture of large slabs of steel during primary processing. Clinking was first observed in reheat furnaces after continuous casting. As slabs are reheated, many catastrophically break apart which causes huge operational disruptions and material loss. As-cast Si slabs were also observed to undergo a similar transverse fracture when left to cool in ambient conditions to below 200°C. The fracture is typically observed to be sub-surface. This paper analyses the as-cast microstructure of the high Si slab. Elements of the microstructure that embrittle the material making it susceptible to the catastrophic fracture, clinking, have been observed. Optical microscopy imaging is completed to understand the grain size, structure and the presence of any inclusions and precipitates. Energy Dispersive X-Ray Spectroscopy (EDX) analysis has been completed to understand the composition of precipitates/inclusions. X-Ray Flourescence (XRF) was completed on samples taken thro gh the thickness t understa d the variation of composition. Charpy tests were undertaken to i vestigate the variation f toughness of the material as a function of the location across the face of the slab. EDX analysis revealed void formation around a MnS particle close to the grain boundary region. Charpy tests showed an improved ductility around 200 ° C, however a ductile brittle transition temperature has not been formally defined due to the lack of samples available. © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. Keywords: Charpy tests, clinking, as-cast microstructure, 1. Introductio Clinking is the term denot d to the catastrophic fracture during th pri ary processing of steel slabs. The fracture is fast and often audible, implying a brittle failure. Clinking can occur as slabs cool down after continuous casting, whilst waiting to be transported to the hot mill for rolling, or when subsequently reheated in furnaces prior to hot rolling. The cracks appear on the slab’s surface in the transverse direction relative to the continuous casting direction and grow through the thickness of the slab as shown in Fig. 1 (a). These cracks can propagate and may cause full fracture of the slab as shown in Fig. 1 (b). The cracks are believed to initiate close to the surface, as shown in Fig. 1 (b). © 2018 The Aut ors. Published by Elsevier B.V. Peer-revi w und r responsibility of the ECF22 organizers. ECF22 - Loading and Environmental effects on Structural Integrity Analysis of an as-cast high Si slab to elucidate fundamental causes of the fracture mechanism: Clinking Guy Khosla a , Daniel Balint a , Didier Farrugia b , Matthew Hole a , Catrin M. Davies a a Department of Mechanical Engineering, Imperial College London, South Kensington Campus, London, UK, SW7 2AZ b TATA Steel UK, Research & Dev lopment, Swinden Technology Ce tre, Rotherham, S60 3AR Abstract ‘Clinking’ refers to the fast and loud transverse fracture of large slabs of steel during primary processing. Clinking was first observed in reheat furnace after c ntinuous ca ting. As slabs are reheated, many catastrophically break apart which causes huge operational disruptions and material loss. As-cast Si slabs were also observed to undergo a similar transverse fracture when left to cool in ambient conditions to b low 200°C. The fract re is typically observed to be sub-surface. This paper analys s t as-cast microstructure of the high Si slab. Elements of the microstructure that mbrittle the material making it susceptibl to the catastrophic fracture, clinking, h ve be n observed. Optical microscopy i aging is co pl ted to understand the grain size, structure and the pr sence of any inclusions and precipitates. Energy Dispersive X-Ray Spectroscopy (EDX) analysis has been completed to understand the composition f precipitates/inclusio s. X-Ray Flourescence (XRF) was completed on samples tak through the thickness to understand the variation of compositi . Charp tests were undertaken to investigate the variation of toughness of the material as a function of the locati n across the face of the slab. EDX a alysis revealed void formation arou d a MnS particle close to the gr in boundary regi n. Charpy tests showed an improved ductility around 200 ° C, however a ductile brittle transition temperature has not been formally defined due to the lack of samples available. © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. Keywords: Charpy tests, clinking, as-cast microstructure, 1. Introduction Clinking is the term denoted to the catastrophic fracture during the primary processing of steel slabs. The fracture is fast and often audible, implying a brittle failure. Clinking can occur as slabs cool down after continuous casting, whilst waiting to be transported to the hot mill for rolling, or when subsequently reheated in furnaces prior to hot rolling. The cracks appear on the slab’s surface in the transverse direction relative to the continuous casting direction and grow through the thickness of the slab as shown in Fig. 1 (a). These cracks can propagate and may cause full fracture of the slab as shown in Fig. 1 (b). The cracks are believed to initiate close to the surface, as shown in Fig. 1 (b). © 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 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 o ganizers.

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.2018.12.300