PSI - Issue 8

ScienceDirect Available online at www.sciencedirect.com Av ilable o line at ww.sciencedire t.com ScienceDirect Structural Integrity Procedia 00 (2016) 000 – 000 Procedia Structu al Integrity 8 (2018) 604–609 Available online at www.sciencedirect.com Structural Integrity Procedia 00 (2017) 000–000 Available online at www.sciencedirect.com Structural Integrity Procedia 00 (2017) 000–000

www.elsevier.com/locate/procedia www.elsevier.com / 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. ∗ Corresponding author. Tel.: + 39-0984-494156 ; fax: + 39-0984-494673. E-mail address: marco.alfano@unical.it 2210-7843 c 2017 The Authors. Published by Elsevier B.V. Peer-revi w under responsibility of the Scientific Committee of AIAS 2017 International Conference on Stress Analysis. ∗ Corresponding author. Tel.: + 39-0984-494156 ; fax: + 39-0984-494673. E-mail address: marco.alfano@unical.it 2210-7843 c 2017 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of AIAS 2017 International Conference on Stress Analysis. * Corresponding author. Tel.: +351 218419991. E-mail address: amd@tecnico.ulisboa.pt 2452-3216 Copyright  2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of AIAS 2017 International Conference on Stress Analysis 10.1016/j.prostr.2017.12.059 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 © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of AIAS 2017 International Conference on Stress Analysis AIAS 2017 International Conference on Stress Analysis, AIAS 2017, 6–9 September 2017, Pisa, Italy Analysis of debonding in bio-inspired interfaces obtained by additive manufacturing Marco Alfano ∗ , Chiara Morano, Luigi Bruno, Maurizio Muzz pappa, Leonardo Pagnott Department of Mechanical, Energy and Management Engineering, University of Calabria, P. Bucci 44C, Italy Abstract The present work is focused on the analysis of fracture in adhesive bonded Double Cantilever Beam (DCB) specimens with 3D printed nylon substrates. The substrates were obtained using selective laser sintering of polyamide powder and embed sub-surface channels with circular and square cross-section. The proposed strategy allows to mimic the crack trapping e ff ect already observed in a multitude of biological materials, that is originated by the spa ial modulation of the driving force available for crack growth. Mechanical tests have shown that the channels induce load fluctuations in the global load-displacement response. A significant increase in the total dissipated energy was observed with respect to bulk samples, i . e . no channels. The observed fluctuations in the global esponse were associated to the sequential storage and sudden release of elastic energy. Indeed, the spatial modulation of the sti ff ness around the interfacial region ultimately a ff ects the crack driving force. c 2017 The Authors. Published by Elsevier B.V. r-review under responsibility of the Scientific Committee of AIAS 2017 International Conference on Stress Analysis. Keywords: sel ctive laser sintering, bio-inspired interfa es, double cantilever b am, crack trapp ng Several works in the broad area of biological materials indicated that the surface and sub-surface features of bush crickets or geckos are provided with extraordinary adhesion properties, see for instance Jagota and Hui (2011). It has been shown that subsurface structures, such as those observed in the barnacles by Hui et al. (2015), enable the so called crack trapping e ff ect. Previous works, such as that of Beese et al. (2014), indicated that crack trapping is com monly observed in biological materials which feature a periodic distribution of phases with distinct sti ff ness within the material architecture. Majumder et al. (2010), A ff errante and Carbone (2011) and A ff errante et al. (2015) highlighted that crack trapping is due to the modulation of the driving force which arises because of the above mentioned sti ff ness variation. The e ff ect has been reproduced experimentally by resorting to standard micro-lithography techniques Glassmaker et al. (2007). More recently, thanks to the ability to fabricate complex geometries, additive manufacturing AIAS 2017 International Conference on Stress Analysis, AIAS 2017, 6–9 September 2017, Pisa, Italy Analysis of debonding in bio-inspired interfaces obtained by additive manufacturing Marco Alfano ∗ , Chiara Morano, Luigi Bruno, Maurizio Muzzupappa, Leonardo Pagnotta Department of Mechanical, Energy and Management Engineering, Univ rsity of Calabria, P. Bucci 44C, Italy Abstract The present work is focused on the analysis of fracture in adhesive bonded Double Cantilever Beam (DCB) specimens with 3D printed nylon substrates. The substrates were obtained using selective laser sintering of polyamide powder and embed sub-surface channels with circular and square cross-section. The proposed strategy allows to mimic the crack trapping e ff ect already observed in a multitude of biological materials, that is originated by the spatial modulation of the driving force available for crack growth. Mechanical tests have shown that the channels induce load fluctuations in the global load-displacement response. A significant increase in the total dissipated energy was observed with respect to bulk samples, i . e . no channels. The observed fluctuations in the global response were associated to the sequential storage and sudden release of elastic energy. Indeed, the spatial modulation of the sti ff ness around the interfacial region ultimately a ff ects the crack driving force. c 2017 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of AIAS 2017 International Conference on Stress Analysis. Keywords: selective laser sintering, bio-inspired interfaces, double cantilever beam, crack trapping 1. Introduction Several works in the broad area of biological materials indicated that the surface and sub-surface features of bush crickets or geckos are provided with extraordinary adhesion properties, see for instance Jagota and Hui (2011). It has been shown that subsurface structures, such as those observed in the barnacles by Hui et al. (2015), enable the so called crack trapping e ff ect. Previous works, such as that of Beese et al. (2014), indicated that crack trapping is com monly observed in biological materials which feature a periodic distribution of phases with distinct sti ff ness within the material architecture. Majumder et al. (2010), A ff errante and Carbone (2011) and A ff errante et al. (2015) highlighted that crack trapping is due to the modulation of the driving force which arises because of the above mentioned sti ff ness variation. The e ff ect has been reproduced experimentally by resorting to standard micro-lithography techniques Glassmaker et al. (2007). More recently, thanks to the ability to fabricate complex geometries, additive manufacturing © 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