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Pomigliano d'Arco, Italy

Swadzba R.,Polish Institute for Ferrous Metallurgy | Wiedermann J.,Polish Institute for Ferrous Metallurgy | Hetmanczyk M.,Silesian University of Technology | Swadzba L.,Silesian University of Technology | And 4 more authors.
Materials and Corrosion | Year: 2014

The study concerns electron beam physical deposition (EB-PVD) of yttria stabilized zirconia (YSZ) deposited on pre-oxidized Pt-modified aluminide bond coating. The coating was prepared by the means of Pt galvanizing followed by vapor phase aluminizing at 1050 °C. During annealing at 1100 °C in air atmosphere for 4 h a 1 μm thick layer of thermally grown oxide (TGO) consisting of equiaxed α-alumina grains was formed. Focused ion beam and scanning/transmission electron microscopy analysis revealed the presence of nanoscale Cr-rich precipitates distributed in the TGO as well as Cr precipitation in the grain boundaries of the β phase at the interface between the TGO and bond coat. Deposition of the YSZ on a pre-oxidized substrate provided mechanical keying with the TGO. Void formation was observed at the TGO and bondcoat interface presumably due to initial transient alumina formation. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Riccio A.,The Second University of Naples | Caputo F.,The Second University of Naples | Tessitore N.,Avio
SDHM Structural Durability and Health Monitoring | Year: 2013

In this paper the mechanical behavior of composites grid structures has been numerically investigated. The evolution of fibers and matrix cracking has been simulated by adopting a progressive damage approach. The Hashin failure criteria and ply properties degradation rules have been adopted to simulate the degradation at ply level. Non-linear analyses on a Representative Volume Element of the composite grid structure have been performed to account for its compression behavior. Copyright © 2013 Tech Science Press.

Germani T.,Europropulsion | Marco T.,Avio | Bouvier F.,HERAKLES | Tamburini A.,Avio | And 3 more authors.
Proceedings of the International Astronautical Congress, IAC | Year: 2012

The ARIANE 5 launcher is boosted by a pair of large Solid Rocket Motor with a diameter of 3 meters and an overall motor length of 27 m. The 480 tons (2× 240) of solid propellant speed up the 200 tons of the Ariane 5 central core at more than Mach 6 in approximately two minutes. Such a performance is obtained with a high level of reliability, demonstrated on Ariane 5 by more than 120 successful flying motors without major issues, and moderate costs compared to alternate propulsion mode. In order to monitor the maintenance of the qualification status of Ariane 5 launch system during its exploitation phase, an Ariane Research and Technology Accompaniment Program (ARTA) is established by ESA and implemented by Europropulsion at motor level and its sub-contractors at components level. Periodic ground firing tests are included in this program with three main objectives: detect potential hardware production or motor performances drifts, qualify new raw materials or technologies due to obsolescence and qualify design changes for flight anomalies treatment. These ground firing test are also used to validate some design evolution as passenger test in order to improve motor behavior and contribute to its industrialization and recurring cost reduction. 1 his paper will tirst summarize the tour ARIA ground tiring tests performed in the past emphasizing the benefits and lessons learned for the production program and then will describe more in details the objectives and results of lastARTA 5 firing test performed on May 2012. Some identified needs and foreseen proposals for the coming firing tests up to the end of the decade will be also presented.©2012 by the International Astronautical Federation.

Laraia M.,University of Naples Federico II | Manna M.,University of Naples Federico II | Cinque G.,Avio | Di Martino P.,Avio
Applied Thermal Engineering | Year: 2013

The paper presents a multi-disciplinary multi-objective design optimization methodology of a combustion chamber effusion cooling system. The optimizer drives an Artificial Neural Network and a Manufacturing Time Model in a repeated analysis scheme in order to increase the combustor liner LCF life and to reduce the liner cooling system manufacturing time, simultaneously. The ANN is trained with a set of fluid/structure/lifing simulations arranged in a three-levels dataset based on a properly designed DOE approach. The CFD simulations are carried out with a reliable and robust in-house developed three-dimensional high resolution reactive viscous flow solver, accounting for conjugate heat transfer approach; the liner structural analysis is performed with a standard FEM code while the liner life assessments are obtained through an in-house developed software operating on the temperature/stress fields. Results demonstrate the validity of the overall approach in a five-dimensional state space with truly moderate computational costs. © 2013 Elsevier Ltd. All rights reserved.

Laraia M.,University of Naples Federico II | Manna M.,University of Naples Federico II | Colantuoni S.,Avio | Di Martino P.,Avio
Combustion Theory and Modelling | Year: 2010

This paper presents a multi-objective optimization procedure as applied to the design of the injection system of a Lean Pre-mixed Pre-vaporized combustion chamber. The optimizer drives an Artificial Neural Network in a repeated analysis scheme in order to simultaneously reduce NOX and CO pollutant emissions. The ANN is trained with a few three-dimensional high resolution reactive viscous flow simulations, carried out with a reliable and robust CFD code. Results, obtained in a four-dimensional state space, demonstrate the validity of the overall procedure with truly moderate computational costs. © 2010 Taylor & Francis.

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