PSI - Issue 12

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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. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/) Peer-review under responsibility of the Scientific Committee of AIAS 2018 International Conference on Stress Analysis. 10.1016/j.prostr.2018.11.099 ∗ Corresponding author. Tel.: + 39-055-275-8707 E-mail address: cesare.certosini@unifi.it 2210-7843 c 2018 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 / 3.0 / ) Peer-review under responsibility of the Scientific Committee of AIAS 2018 International Conference on Stress Analysis. In the automotive and motorsport fields, there has been great focus in the past years on the development of active systems to control vehicle behaviour, thus improving handling and safety. This has been enhanced by the increasing integration between di ff erent engineering sectors such as mechanics and electronics. One of these devices is the semi-active di ff erential (SAD). This di ff erential allows the amount of locking percentage to be controlled through the use of a hydraulic actuator. Control is completely electronic and governed by a bespoke ECU. The possibility of controlling the locking percentage is what makes this di ff erential an upgrade to the standard limited slip di ff erential (LSD) mounted on most racing vehicles since it improves the understeer / oversteer balance of the car, specifically in conditions such as braking in turn and power on cornering. In order to fully control the friction torque generated by the clutch it is important to know the local friction coe ffi cient. However, since friction is a non-conservative force there is a great amount of heat generated. Such heat obviously tends to raise the temperature of the discs, varying the friction coe ffi cient and, therefore, the amount of redistributed torque. There are multiple other factors ∗ Corresponding author. Tel.: + 39-055-275-8707 E-mail address: cesare.certosini@unifi.it 2210-7843 c 2018 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 / 3.0 / ) Peer-review under responsibility of the Scientific Committee of AIAS 2018 Internatio al 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. © 2018 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/3.0/) Peer-review under responsibility of the Sc entific Committee of AIAS 2018 International C nference o Stress Analysis. AIAS 2018 International Conference on Stress Analysis FEM thermal analysis of a semi-active di ff erential T. Novi a , C. Carcasci a , C. Certosini a, ∗ , R. Capitani a , C. Annicchiarico b a Universita` degli Studi di Firenze - Dipartimento di Ingegneria Industriale, Via di Santa Marta 3, 50139 Firenze, Italy b Meccanica 42 s.r.l., Via Madonna del Piano 6, 50019 Sesto fiorentino (FI), Italy Abstract A semi-active di ff erential (SAD) is a device which allows the flaws of a standard limited slip di ff erential (LSD) to be overcome in terms of how they a ff ect vehicle dynamics. This is possible by controlling continuously the locking percentage. A thermal analysis of a semi-active di ff erential (SAD) is presented. An internal electro-hydraulic clutch produces a resistant torque in the analysed device, therefore, the locking percentage is highly influenced by temperature. Steady and transient conditions are evaluated under various conditio s of actuat on system pressure and relative rotational locity between the clutch’s discs. The radial and axial temperature distribution together with the temperature gradient along the contact surfaces generating friction have been characterized, including the case of a duty cycle. c 2018 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 / 3.0 / ) Peer-review under responsibility of the Scientific Committee of AIAS 2018 International Conference on Stress Analysis. Keywords: Semi-active di ff erential; Thermal FEM; Unsteady state; H at transfer; Axisymmetric; Wet Clutch 1. Introduction In the automotive and motorsport fields, there has been great focus in the past years on the development of active systems to control vehicle behaviour, thus improving handling and safety. This has been enhanced by the increasing integration between di ff erent engineering sectors such as mechanics and electronics. One of these devices is the semi-active di ff erential (SAD). This di ff erential allows the amount of locking percentage to be controlled through the use of a hydraulic actuator. Control is completely electronic and governed by a bespoke ECU. The possibility of controlling the locking percentage is what makes this di ff erential an upgrade to the standard limited slip di ff erential (LSD) mounted on most racing vehicles since it improves the understeer / oversteer balance of the car, specifically in conditions such as braking in turn and power on cornering. In order to fully control the friction torque generated by the clutch it is important to know the local friction coe ffi cient. However, since friction is a non-conservative force there is a great amount of heat generated. Such heat obviously tends to raise the temperature of the discs, varying the friction coe ffi cient and, therefore, the amount of redistributed torque. There are multiple other factors AIAS 2018 International Conference on Stress Analysis F ther al analysis of a se i-active di erential T. Novi a , C. Carcasci a , C. Certosini a, ∗ , R. Capitani a , C. Annicchiarico b a Universita` degli Studi di Firenze - Dipartimento di Ingegneria Industriale, Via di Santa Marta 3, 50139 Firenze, Italy b Meccanica 42 s.r.l., Via Madonna del Piano 6, 50019 Sesto fiorentino (FI), Italy Abstract A semi-active di ff erential (SAD) is a device which allows the flaws of a standard limited slip di ff erential (LSD) to be overcome in terms of how they a ff ect vehicle dynamics. This is possible by co trolling continuously the lo king percentage. A thermal analysis of a semi-active di ff erential (SAD) is presented. An internal electro-hydraulic clutch produces a resistant torque in the analysed device, therefore, the locking percentage is highly influenced by temperature. Steady and transient conditions are evaluated under various conditions of actuation system pressure and relative rotational velocity between the clutch’s discs. The radial and axial temperature distribution together with the temperature gradient along the contact surfaces generating friction have been characterized, including the case of a duty cycle. c 2018 The Authors. Published by Elsevier B.V. i is an open access article under the CC BY- C-ND license (http: // creativecommons.org / licenses / by-nc-nd / 3.0 / ) er-review unde responsibility of the Scientific Committee of AIAS 2018 Internatio al Co ferenc on Stress Analysis. Keywords: Semi-active di ff erential; Thermal FEM; Unsteady state; Heat transfer; Axisymmetric; Wet Clutch 1. Introduction © 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