The Experts below are selected from a list of 1635 Experts worldwide ranked by ideXlab platform
Guopeng Zhang - One of the best experts on this subject based on the ideXlab platform.
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Semiconductivities of passive films formed on stainless steel bend under erosion-corrosion conditions
Corrosion Science, 2018Co-Authors: L. Zeng, X.p. Guo, Guopeng Zhang, Hanxin ChenAbstract:Abstract Semiconductivities of passive films at a stainless steel bend in sand-containing NaCl solution under erosion-corrosion (E-C) conditions were investigated by Mott-Schottky analysis. It is demonstrated that higher donor densities and faster diffusivities of point defects within passive film appear at the Extrados of the bend. X-ray photoelectron spectroscopy (XPS) analysis reveals that the passive layer at the Extrados of bend contains less Fe3O4 and Fe2O3. The semiconductivities of passive films are strongly dependent on the hydrodynamic characteristics at the bend.
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Inhibition of the erosion-corrosion of a 90° low alloy steel bend
Journal of Alloys and Compounds, 2017Co-Authors: L. Zeng, X.p. Guo, Guopeng ZhangAbstract:Abstract The inhibition effect of inhibitor on the erosion-corrosion (E-C) of a low alloy steel bend is investigated by weight loss, electrochemical measurements, and surface analysis. It is demonstrated that inhibitor can significantly reduce the E-C rate and effectively inhibit the four components (pure corrosion, pure erosion, corrosion-enhanced erosion, and erosion-enhanced corrosion) of E-C. The inhibition of corrosion is more pronounced than that of erosion. The inhibition efficiencies (IEs) for total E-C, pure erosion, corrosion-enhanced erosion, and erosion-enhanced corrosion at the intrados are higher than that at the Extrados of the bend. The lower IEs at the Extrados are due to the severe sand particle impact and detrimental hydrodynamics conditions at these positions.
L. Zeng - One of the best experts on this subject based on the ideXlab platform.
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Semiconductivities of passive films formed on stainless steel bend under erosion-corrosion conditions
Corrosion Science, 2018Co-Authors: L. Zeng, X.p. Guo, Guopeng Zhang, Hanxin ChenAbstract:Abstract Semiconductivities of passive films at a stainless steel bend in sand-containing NaCl solution under erosion-corrosion (E-C) conditions were investigated by Mott-Schottky analysis. It is demonstrated that higher donor densities and faster diffusivities of point defects within passive film appear at the Extrados of the bend. X-ray photoelectron spectroscopy (XPS) analysis reveals that the passive layer at the Extrados of bend contains less Fe3O4 and Fe2O3. The semiconductivities of passive films are strongly dependent on the hydrodynamic characteristics at the bend.
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Inhibition of the erosion-corrosion of a 90° low alloy steel bend
Journal of Alloys and Compounds, 2017Co-Authors: L. Zeng, X.p. Guo, Guopeng ZhangAbstract:Abstract The inhibition effect of inhibitor on the erosion-corrosion (E-C) of a low alloy steel bend is investigated by weight loss, electrochemical measurements, and surface analysis. It is demonstrated that inhibitor can significantly reduce the E-C rate and effectively inhibit the four components (pure corrosion, pure erosion, corrosion-enhanced erosion, and erosion-enhanced corrosion) of E-C. The inhibition of corrosion is more pronounced than that of erosion. The inhibition efficiencies (IEs) for total E-C, pure erosion, corrosion-enhanced erosion, and erosion-enhanced corrosion at the intrados are higher than that at the Extrados of the bend. The lower IEs at the Extrados are due to the severe sand particle impact and detrimental hydrodynamics conditions at these positions.
Gabriele Milani - One of the best experts on this subject based on the ideXlab platform.
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Single lap shear tests of masonry curved pillars externally strengthened by CFRP strips
Composite Structures, 2018Co-Authors: Tommaso Rotunno, Mario Fagone, Elisa Bertolesi, Ernesto Grande, Gabriele MilaniAbstract:Abstract The paper presents an experimental study concerning the bond behaviour of Carbon Fiber Reinforced Polymers (CFRP) sheet reinforcements applied to curved masonry surfaces. Such strengthening technique is more and more used in structural rehabilitation and retrofitting of existing buildings. Its effectiveness has been demonstrated by several studies published in the literature, mostly devoted to flat bonded surfaces. Observing that CFRPs are extensively applied on arches and vaults but only few research activities concern curved bonded surfaces, the experimental study described in this paper is aimed to contribute to fill this gap. The experimental program was carried out on portions of masonry arches, reinforced by CFRP sheets bonded at Extrados or intrados, tested by a single lap shear test. The experimental results allowed to analyse the effectiveness of such reinforcements, loaded by actions tangent to an end of the reinforcement itself, with respect to its position (intrados or Extrados) and to the curvature of the bonding surface. As expected, the results highlight that the bond behaviour strongly depend on the position of the reinforcement. In particular, the capacity of reinforcements bonded at the Extrados increases with the curvature, while decreases with the curvature for those bonded at intrados.
Patrick Terriault - One of the best experts on this subject based on the ideXlab platform.
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development of a morphing wing Extrados made of composite materials and actuated by shape memory alloys
Journal of Intelligent Material Systems and Structures, 2017Co-Authors: Jeanrene Poulin, Patrick Terriault, Martine Dube, Pierreluc VachonAbstract:This article focuses on the development of a shape morphing composite skin representing a wing Extrados. The objective is to design and manufacture a skin capable of changing its geometry in order ...
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SMA actuators for morphing wings
Physics Procedia, 2010Co-Authors: Vladimir Brailovski, Patrick Terriault, T. Georges, D. CoutuAbstract:An experimental morphing laminar wing was developed to prove the feasibility of aircraft fuel consumption reduction through enhancement of the laminar flow regime over the wing Extrados. The morphing wing prototype designed for subsonic cruise flight conditions (Mach 0.2⋯0.3; angle of attack -1⋯+2°), combines three principal subsystems: (1) flexible Extrados, (2) rigid intrados and (3) an actuator group located inside the wing box. The morphing capability of the wing relies on controlled deformation of the wing Extrados under the action of shape memory alloys (SMA) actuators. A coupled fluid-structure model of the morphing wing was used to evaluate its mechanical and aerodynamic performances in different flight conditions. A 0.5 m chord and 1 m span prototype of the morphing wing was tested in a subsonic wind tunnel. In this work, SMA actuators for morphing wings were modeled using a coupled thermo-mechanical finite element model and they were windtunnel validated. If the thermo-mechanical model of SMA actuators presented in this work is coupled with the previously developed structureaerodynamic model of the morphing wing, it could serve for the optimization of the entire morphing wing system.
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Optimized design of an active Extrados structure for an experimental morphing laminar wing
Aerospace Science and Technology, 2010Co-Authors: D. Coutu, Vladimir Brailovski, Patrick TerriaultAbstract:Abstract This paper focuses on the design of an active Extrados structure for an experimental morphing laminar wing, which has been tested in a subsonic wind tunnel. Actuators localized inside the wing box apply individually controlled displacements over the flexible structure, made from laminate composite, to modify the airfoil profile in accordance with the database, which is built using XFoil aerodynamic solver. This database contains a set of wing profiles, which maximize laminar flow under a given set of cruise flight conditions: Mach number 0.2 to 0.35 and attack angles −1 to 2 ° . A finite elements structural model of the active Extrados has been developed with ANSYS software. Two main design parameters were identified: the number of plies in the composite laminate of the flexible Extrados and the number of actuators. To balance the tradeoff between stiffness and flexibility of the active Extrados structure, aerodynamic (laminar flow regime enhancement) and mechanical (low strain energy) performance criteria were considered simultaneously. Using the multi-objective optimization technique, the designer's preferences led to the selection of the 4-ply 2-actuator active Extrados structure configuration.
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Design of Shape Memory Alloy Actuators for Morphing Laminar Wing With Flexible Extrados
Journal of Mechanical Design, 2009Co-Authors: T. Georges, D. Coutu, Vladimir Brailovski, Emeric Morellon, Patrick TerriaultAbstract:An active structure of a morphing wing designed for subsonic cruise flight conditions is composed of three principal subsystems: (1) fexible Extrados, (2) rigid intrados, and (3) an actuator group located inside the wing box. The four-ply laminated composite flexible Extrados is powered by two individually controlled shape memory alloy (SMA) actuators. Fulfilling the requirements imposed by the morphing wing application to the force-displacement characteristics of the actuators, a novel design methodology to determine the geometry of the SMA active elements and their adequate assembly conditions is presented. This methodology uses the results of the constrained recovery testing of the selected SMA. Using a prototype of the morphing laminar wing powered by SMA actuators, the design approach proposed in this study is experimentally validated.
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Wind-tunnel testing of shape memory alloys actuators as morphing wing driving systems
Volume 2: Multifunctional Materials; Enabling Technologies and Integrated System Design; Structural Health Monitoring NDE; Bio-Inspired Smart Material, 2009Co-Authors: T. Georges, D. Coutu, Vladimir Brailovski, Emeric Morellon, Patrick TerriaultAbstract:A morphing wing, composed of flexible Extrados, rigid intrados and a Shape Memory Alloys (SMA) actuator group located inside the wing box, is used to adapt an airfoil profile to variable flight conditions. The SMA actuator group developed for the morphing wing prototype consists of three main subsystems: the SMA active element, the transmission system, and the passive bias element. The functional requirements for the actuator group were determined using a coupled fluid-structure model of the flexible Extrados. An original design approach was applied to determine the geometry and assembly conditions of the SMA active elements. For validation purposes, the morphing wing powered by SMA actuators was tested in a wind tunnel under subsonic flight conditions (Mach = 0.2 to 0.3 and α = −1 to 2°). The ability of the actuator group to move the flexible Extrados up to 8 mm of vertical displacement and to bring it back to the initial profile has been successfully proven for all of the wind tunnel testing conditions. During the repetitive actuation, the force, displacement and temperature of the SMA active elements were measured and the results obtained in the force-displacement-temperature space were used to validate the SMA performances predicted during the design phase.Copyright © 2009 by ASME
X.p. Guo - One of the best experts on this subject based on the ideXlab platform.
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Semiconductivities of passive films formed on stainless steel bend under erosion-corrosion conditions
Corrosion Science, 2018Co-Authors: L. Zeng, X.p. Guo, Guopeng Zhang, Hanxin ChenAbstract:Abstract Semiconductivities of passive films at a stainless steel bend in sand-containing NaCl solution under erosion-corrosion (E-C) conditions were investigated by Mott-Schottky analysis. It is demonstrated that higher donor densities and faster diffusivities of point defects within passive film appear at the Extrados of the bend. X-ray photoelectron spectroscopy (XPS) analysis reveals that the passive layer at the Extrados of bend contains less Fe3O4 and Fe2O3. The semiconductivities of passive films are strongly dependent on the hydrodynamic characteristics at the bend.
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Inhibition of the erosion-corrosion of a 90° low alloy steel bend
Journal of Alloys and Compounds, 2017Co-Authors: L. Zeng, X.p. Guo, Guopeng ZhangAbstract:Abstract The inhibition effect of inhibitor on the erosion-corrosion (E-C) of a low alloy steel bend is investigated by weight loss, electrochemical measurements, and surface analysis. It is demonstrated that inhibitor can significantly reduce the E-C rate and effectively inhibit the four components (pure corrosion, pure erosion, corrosion-enhanced erosion, and erosion-enhanced corrosion) of E-C. The inhibition of corrosion is more pronounced than that of erosion. The inhibition efficiencies (IEs) for total E-C, pure erosion, corrosion-enhanced erosion, and erosion-enhanced corrosion at the intrados are higher than that at the Extrados of the bend. The lower IEs at the Extrados are due to the severe sand particle impact and detrimental hydrodynamics conditions at these positions.
