PSI - Issue 13

ScienceDirect Available online at www.sciencedirect.com Av ilable o line at ww.sciencedirect.com ienceDirect Structural Integrity Procedia 00 (2016) 000 – 000 Procedia Structu al Integrity 13 (2018) 819–824 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 Mechanical modelling of self-diagnostic polymers Roberto Brighenti a *, Federico Artoni a a Department of Engineering & Architecture, University of Parma, Parco Area delle Scienze 181/A, 43124 Parma, Italy Abstract The safety level in advanced load bearing applications can be enhanced if the material would be able to detect the in-service deformation, allowing a real time evaluation of the reliability state of the components. Polymeric materials can be used to get such a functionality through the insertion of so-called mechanophore units, whose main property is to chemically respond to mechanical stimuli. In the present paper, a micromechanical approach is developed to model the response of polymers containing reporting units, whose activa ion is triggered by the d formation of the underneath netwo k or by a chemical stimulus. The model, through an Arrhenius-like equilibrium reaction law, provides a quantitative evaluation of the fraction of stress-activated molecules. Moreover, if the mechanophore activation involves also a change in their geometrical conformation, it influences the network deformation and the corresponding mechanical effects must be also accounted for. The formulated micromechanical model is presented and implemented in a FE code in order to simulate structural elements made of a self-diagnostic material. In particular, we consider the fluorescence-based strain detection of pre-cracked elements made of polymers with supramolecular complexes cross-linked to the polymer’s chains; the fluorescence intensity is assumed to be proportional to the volume fraction of the activated units, thus enabling to quantify the associated material’s strain value. © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. Keywords: polymers; mechanophores; self-diagnostic; micro-mechanical model. 1. Introduction Polymers are materials that can be usefully applied in high-performance applications, because through their microstructure they can be designed in order to get a desired behavior in response to external stimuli. Especially by using polymers in high demanding applications, the necessity to check their integrity in an easy and cheap way can be © 2018 The Authors. P blished by Elsevier B.V. Peer-review und responsibility of the ECF22 organiz rs. ECF22 - Loading and Environmental effects on Structural Integrity Mechanical modelling of self-diagnostic polymers Roberto Brighenti a *, Federico Artoni a a Department of Engineering & Architecture, University of Parma, Parco Area delle Scienze 181/A, 43124 Parma, Italy Abstract The safety level in advanced load bearing applications can be enhanc d if the material would be able to detect the in-service deformation, allowing a real time evaluation of the reliability stat of the components. Polymeric materials can b used to get su h a functionality through th insertion of so-called mechanophore units, whose main propert is to chemically respond to mechanical stimuli. In the present paper, a micromech nical approach is developed to model the response of polymers containing reporting units, whose activation is triggered by the deform tion of the und rneath network or by a chemical stimulu . The model, through a Arrhenius-like equilibrium r a tion law, provides a quantitativ evaluation f th fraction of stress-activated molecules. Moreov r, if the mechanophore activation involves also a change in their ge metrical conformation, it influences the n twork deformation and th corresp nding mechanical effects must be also accounted for. The formul ted micromechanical model is presented a d implemented in a FE code in order to simulate structural elements made of a self-diagnosti material. In particular, w consider the fluoresc nce-based strain detection of pre-cracked elem nts made of polymers with supramolecular complexes cross-linked to the p lym r’s ch ins; the fluores ence intensity is assumed to be proportional to the volume fraction of the activat d units, thus enabling to quantify the associated material’s strain value. © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. Keywords: polymers; mechanophores; self-diagnostic; micro-mechanical model. 1. Introduction Polymers are materials that can be usefully applied in high-performance applications, because through their microstructure they can be designed in order to get a desired behavior in response to external stimuli. Especially by using polymers in high demanding applications, the necessity to check their integrity in an easy and cheap way can be © 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. * Corresponding author. Tel.: +39 0521 905910; fax: +39 0521 905924. E-mail address: brigh@unipr.it * Corresponding author. Tel.: +39 0521 905910; fax: +39 0521 905924. E-mail ad ress: brigh@unipr.it

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.2018.12.157