PSI - Issue 8

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ScienceDirect Available online at www.sciencedirect.com Av ilable o line at ww.sciencedire t.com ienceDirect Structural Integrity Procedia 00 (2016) 000 – 000 Procedia Structu al Integrity 8 (2018) 227–238 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2017) 000 – 000 Structural Integrity Procedia 00 (2017) 000 – 000

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www.elsevier.com/locate/procedia AIAS 2017 International Conference on Stress Analysis, AIAS 2017, 6-9 September 2017, Pisa, Italy Design of an under-bonnet heat exchanger for the improvement of energy efficiency Claudio Fichera a , Massimiliano Avalle b, * a CERN, Route de Meyrin 385, 1217 Meyrin, Switzerland b Università degli Studi di Genova, Via all’Opera Pia 15, 16145 Genoa, Italy The present work is aim d t reporting the methodology used to develop an nnovative type of heat exchanger to exploit the free space under the upper skin of a car bonnet between the stiffener ribs. The idea is to take advantage of the large surface of the bonnet itself as a radiating area to increase the heat exchange capacity of the cooling system to save energy and improve the overall vehicle effi iency. The heat exchanger can be built with a thin-shell under-bonnet properly shaped that, fixed below the lower surface of the bonnet skin, realizes a closed chamber where the cooling fluid can pass and exchange heat. With the aim of weight reduction, the thin-shell under-bonnet will be made of plastic material and the technology to fix it and create the closed chamber will be, necessarily, structural bonding. To this aim, it has been necessary to develop a methodology to characterize the metal-to-plastic adhesive joint to design and verify the proposed solution. In the work, the experimental method consisting of a C-shaped metal half-specimen (made of steel, and obtained from a sample of a vehicle bonnet) on a plastic plate of the material used for the thin shell under-bonnet will be illustrated. The adhesion properties of the joint hav been then obtained by means of th inverse method with a p rametric numerical model reproducing in detail the experimental test in order to identify the parameters of th mat rial model used to describe t e adhesive behavior. The necessity of this type of test depends on the type of applied load, mainly direct pull-out, and the type of joined parts and materials. Once the adhesive model parameters obtained, they have been used to virtually study a prototype of the heat exchanger to obtain a suitable solution in terms of thermo-mechanical strength and energetic efficiency. © 2017 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 Design of an under-bonnet heat exchanger for the impr v ment of energy efficiency Claudio Fichera a , Massimiliano Avalle b, * a CERN, Route de Meyrin 385, 1217 Meyrin, Switzerland b Università degli Studi di Genova, Via all’Opera Pia 15, 16145 Genoa, Italy Abstract The present work is aimed at reporting the met odology used to develop an innovative type of heat exchanger to exploit the free space u der the upper skin of a car bonnet betwe n the stiffener ribs. The idea is to take advantage of the large surface of the bonnet itself as a radiating area to increase the heat exchange c pacity of the cooling system to save energy and impr ve the overall vehicle efficiency. The heat exchanger can be built wit a thin-sh ll under-bonnet properly shaped that, fixed below the lower surface of the onnet skin, realizes clos d chamber where the cooling fluid can pass and exchange heat. With the aim f weight reduction, the thin-shell under-b nnet will be m de of plastic aterial nd the technology to fix it and create the closed chamber will be, necessarily, structural bonding. To this aim, it has been necessary to develop a methodology to characterize the metal-to-plastic adhesive joint to design and verify the proposed solution. In the work, the xperimental method consisting of a C-shaped met l half-specimen (made of steel, and obtained from a sample of a vehicle b nn t) on a plastic plate of the material used for the thin shell under-bonnet will be illustr ted. The adhesion properties of the joint have been then obtained by me ns of the inverse method with a parametric numerical model reproducing in detail the experimental test in order to identify the param ters of the material model used to describe the adhesive behavior. The necessity of this type of test depends on the type of applied load, mainly direct pull-out, and the type of joined parts and materials. Once the adhesive model parameters obtained, they have been used to virtually study a prototype of the heat exchanger to obtain a suitable solution in terms of thermo-mechanical strength and energetic efficiency. © 2017 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Com ittee of AIAS 2017 International Conference on Stress Analysis. 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. © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of PCF 2016. 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 Abstract

Keywords: High Pressure Turbine Blade; Creep; Finite Element Method; 3D Model; Simulation.

* Corresponding author. Tel.: +39-010-3532241; fax: +39-010-3532834. E-mail address: massimiliano.avalle@unige.it

2452-3216 © 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.: +39-010-3532241; fax: +39-010-3532834. E-mail address: massimiliano.avalle@unige.it

2452-3216 © 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 © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of PCF 2016.

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.2017.12.025