ORBi Collection: Aerospace & aeronautics engineering
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A study of composite laminates failure using an anisotropic gradientenhanced damage meanfield homogenization model
http://hdl.handle.net/2268/178536
Title: A study of composite laminates failure using an anisotropic gradientenhanced damage meanfield homogenization model
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<br/>Author, coauthor: Wu, Ling; Sket, Federico; MolinaAldareguia, Jon M; Makradi, Ahmed; Adam, Laurent; Doghri, Issam; Noels, Ludovic
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<br/>Abstract: The failure of carbon fiber reinforced epoxy laminates is studied using an anisotropic gradientenhanced continuum damage model embedded in a meanfield homogenization scheme.
In each ply, a homogenized material law is used to capture the intralaminar failure. The anisotropy of the homogenized material model results from the homogenization method and from the reformulation of the nonlocal continuum damage theory to account for the material anisotropy. As a result the damage propagation direction in each ply is predicted with accuracy as compared to the experimental results, while the problems of losing uniqueness and strain localization, which occur in classical finite element simulations when strain softening of materials is involved, can be avoided.
To model the delamination process, the hybrid discontinuous Galerkin/extrinsic cohesive law method is introduced at the ply interfaces. This hybrid method avoids the need to propagate topological changes in the mesh with the propagation of the delamination while it preserves the consistency and stability in the uncracked interfaces.
As a demonstration, openhole coupons with different stacking sequences are studied numerically and experimentally.
Both the intra and interlaminar failure patterns are shown to be well captured by the computational framework.
Sun, 22 Feb 2015 11:20:39 GMT

Regressionbased modelling of a fleet of gas turbine engines for performance trending
http://hdl.handle.net/2268/178530
Title: Regressionbased modelling of a fleet of gas turbine engines for performance trending
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<br/>Author, coauthor: Borguet, Sébastien; Léonard, Olivier; Dewallef, Pierre
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<br/>Abstract: Module performance analysis is a wellestablished framework
to assess changes in the health condition of the components
of the engine gaspath. The primary material of the technique is
the socalled vector of residuals, which are built as the difference
between actual measurement taken in the gaspath and values
predicted by means of an engine model. Obviously, the quality of
the assessment of the engine condition depends strongly on the
accuracy of the engine model.
The present paper proposes a new approach for datadriven
modelling of a fleet of engines of a given type. Such blackbox
models can be designed by operators such as airlines and thirdparty
companies. The fleetwide modelling process is formulated
as a regression problem that provides a dedicated model for each
engine in the fleet, while recognising that all engines are of the
same type. The methodology is applied to a virtual fleet of engines
generated within the ProDiMES environment. The set of
models is assessed quantitatively through the coefficient of determination
and is further used to perform anomaly detection.
Sat, 21 Feb 2015 12:33:44 GMT

A complete closed form vectorial solution to the Kepler problem
http://hdl.handle.net/2268/178262
Title: A complete closed form vectorial solution to the Kepler problem
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<br/>Author, coauthor: Condurache, D.; Martinusi, Vladimir
<br/>
<br/>Abstract: The paper gives an exact vectorial solution to the Kepler problem. A vectorial regularization that linearizes the Kepler problem is given using a Sundman transformation. Closed form expressions describing the Keplerian motion are deduced. A unified approach to the classic Kepler problem is offered, by studying both rectilinear and nonrectilinear Keplerian motions with the same instrument. The approach is an elementary one and only simple vectorial computations are involved. © 2007 Springer Science+Business Media B.V.
Thu, 12 Feb 2015 11:40:52 GMT

Exact solution to the relative orbital motion in a central force field
http://hdl.handle.net/2268/178261
Title: Exact solution to the relative orbital motion in a central force field
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<br/>Author, coauthor: Condurache, D.; Martinusi, Vladimir
<br/>
<br/>Abstract: The paper presents the exact solution to the relative orbital motion that takes place in a central force field.This problem is a generalization of the problem of the Keplerian relative motion in a central force field. The solution is presented in a coordinate free vectorial form, offering closed form expressions for the law of motion and the velocity. The solution is offered to the nonlinear model of the relative motion problem, and itgeneralizes the solutions found by ClohessyWiltshire, Lawden and TschaunerHempel for the case of the Keplerian relative motion. The applications of this problem are in satellite formation flying, satellite constellations and orbital rendezvous.
Thu, 12 Feb 2015 11:39:32 GMT

Analytic solution to the relative orbital motion around an oblate planet
http://hdl.handle.net/2268/178260
Title: Analytic solution to the relative orbital motion around an oblate planet
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<br/>Author, coauthor: Condurache, D.; Martinusi, Vladimir
<br/>
<br/>Abstract: The paper offers a vectorial approach to the J2perturbed relative orbital motion. The model uses mean orbital elements in order to derive closed form expressions for the relative position and relative velocity with respect to the LVLH frame attached on a main satellite. The advantage of the present approach is that only the motion of one satellite must be known, together with the initial conditions with respect to LVLH of the other satellites. As in the previous works of the authors, a tensorial instrument is used in order to transfer the motion from inertial to noninertial reference frames and back. In this way, a concise instrument for the study of the satellites formations under the influence of the oblateness factor J2 is offered. Copyright © 2009 by Daniel Condurache and Vladimir Martinusi.
<br/>
<br/>Commentary: 81960
9781563479786
Thu, 12 Feb 2015 11:36:28 GMT

Hypercomplex eccentric anomaly in the unified solution to the relative orbital motion
http://hdl.handle.net/2268/178259
Title: Hypercomplex eccentric anomaly in the unified solution to the relative orbital motion
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<br/>Author, coauthor: Condurache, D.; Martinusi, Vladimir
<br/>
<br/>Abstract: The present work offers an approach to the relative orbital motion by using hypercomplex algebra. An extension to this notion is used for vectors, by introducing the hypercomplex vector in the same way as hypercomplex numbers are defined. The solution to the relative orbital motion is offered in all possible situations (it stands for any Keplerian reference or targeted trajectories). A unified view on the relative orbital motion is suggested, by generalizing the previous approaches. The solution is offered to the nonlinear model of the relative motion and it is expressed in a coordinatefree hypercomplex vectorial closed form. The key element of this approach is the hypercomplex eccentric anomaly, introduced via a Sundmanlike vectorial regularization.
<br/>
<br/>Commentary: 86723
9780877035572
Thu, 12 Feb 2015 11:33:39 GMT

Closedform solutions for satellite relative motion in an axiallysymmetric gravitational field
http://hdl.handle.net/2268/178258
Title: Closedform solutions for satellite relative motion in an axiallysymmetric gravitational field
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<br/>Author, coauthor: Martinusi, Vladimir; Gurfil, P.
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<br/>Abstract: A different approach is proposed for the study of satellite relative motion in an axiallysymmetric gravitational field. Instead of using the Keplerian motion as the generating nominal orbit for the absolute motion, another "unperturbed" orbit is proposed instead: An equatorial orbit about an oblate planet. Based on the superintegrability of such motion, closedform solutions for the equatorial relative motion are obtained. Analytic conditions for the periodicity of the relative motion in a generic central force field are presented, and utilized to design longterm bounded relative motion under highorder even zonal perturbations.
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<br/>Commentary: 86783
9780877035695
Thu, 12 Feb 2015 11:32:17 GMT

State Space Analysis for The Relative Spacecraft Motion in Geopotential fields
http://hdl.handle.net/2268/178257
Title: State Space Analysis for The Relative Spacecraft Motion in Geopotential fields
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<br/>Author, coauthor: Condurache, Daniel; Martinusi, Vladimir
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<br/>Abstract: The paper offers an approach to the relative orbital motion from a new point of view, which introduces a unified way to approach both the relative position and the relative velocity with the help of a single appropriately defined tensor operator. In the situation of an unperturbed gravitational field, this operator is written with respect to the eccentric anomaly associated to the deputy spacecraft inertial orbit. In the situation of the relative equatorial motion around an oblate planet, the operator may be written with the help of elliptic integrals. The six dimensional curve in the state space (position and velocity) is completely described with the help of the parametrization which emerges from the present approach. The applications are in orbit initialization, rendezvous and docking maneuvers, as well as it constitutes a basis for propagating nominal integrable orbits when dealing with perturbations. © 2011 by Daniel Condurache and Vladimir Martinusi.
<br/>
<br/>Commentary: 97951
9781600869525
Thu, 12 Feb 2015 11:30:32 GMT

A closed form solution of the two body problem in noninertial reference frames
http://hdl.handle.net/2268/178254
Title: A closed form solution of the two body problem in noninertial reference frames
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<br/>Author, coauthor: Condurache, Daniel; Martinusi, Vladimir
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<br/>Abstract: A comprehensive analysis, together with the derivation of a closed form solution to the twobody problem in arbitrary noninertial reference frames are made within the present work. By using an efficient mathematical instrument, which is closely related to the attitude kinematics methods, the motion in the noninertial reference frame is completely solved. The closed form solutions for the motion in the noninertial frame, the motion of the mass center, and the relative motion are presented in the paper. Dynamical characteristics analogue to the linear momentum, angular momentum and total energy are introduced. In the general situation, these quantities may be determined as functions of time, and their derivation is presented within the paper. In the situation where the noninertial frame has only a rotation motion, these quantities become first integrals in a larger sense, with respect to an adequately defined differentiation rule.
Thu, 12 Feb 2015 11:28:41 GMT

Universal functions in the study of the relative orbital dynamics
http://hdl.handle.net/2268/178253
Title: Universal functions in the study of the relative orbital dynamics
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<br/>Author, coauthor: Condurache, Daniel; Martinusi, Vladimir
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<br/>Abstract: The closedform solution to the problem of the relative motion in gravitational fields is expressed with the help of the universal functions. The full nonlinear model of the relative motion is considered, and no linearization or approximation assumptions are made. The results are free of singularities and they hold for any reference and targeted orbits, as well as for any time scale. A unified way to propagate the relative orbit with respect to time is introduced, by making use of the solution to a generalized Kepler equation.
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<br/>Commentary: 96170
9780877035879
Thu, 12 Feb 2015 11:25:46 GMT

Analytic Models for Orbit Propagation in the Presence of Oblateness and Atmospheric Drag
http://hdl.handle.net/2268/178186
Title: Analytic Models for Orbit Propagation in the Presence of Oblateness and Atmospheric Drag
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<br/>Author, coauthor: Martinusi, Vladimir; Dell'Elce, Lamberto; Kerschen, Gaëtan
Tue, 10 Feb 2015 11:06:06 GMT

ClosedForm Solutions for Open Orbits Around an Oblate Planet
http://hdl.handle.net/2268/178184
Title: ClosedForm Solutions for Open Orbits Around an Oblate Planet
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<br/>Author, coauthor: Martinusi, Vladimir; Gurfil, Pini
Tue, 10 Feb 2015 10:53:12 GMT

Universal Functions in the Study of the Relative Orbital Motion
http://hdl.handle.net/2268/178182
Title: Universal Functions in the Study of the Relative Orbital Motion
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<br/>Author, coauthor: Condurache, Daniel; Martinusi, Vladimir
Tue, 10 Feb 2015 10:46:36 GMT

Keplerization of Motion in Any Central Force Field
http://hdl.handle.net/2268/178177
Title: Keplerization of Motion in Any Central Force Field
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<br/>Author, coauthor: Martinusi, Vladimir; Gurfil, Pini
Tue, 10 Feb 2015 10:25:21 GMT

Analytical Orbit Propagator Based on Vectorial Orbital Elements
http://hdl.handle.net/2268/178174
Title: Analytical Orbit Propagator Based on Vectorial Orbital Elements
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<br/>Author, coauthor: Condurache, Daniel; Martinusi, Vladimir
Tue, 10 Feb 2015 10:20:41 GMT

Kepler's Problem in Rotating Reference Frames Part II: Relative Orbital Motion
http://hdl.handle.net/2268/178160
Title: Kepler's Problem in Rotating Reference Frames Part II: Relative Orbital Motion
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<br/>Author, coauthor: Condurache, Daniel; Martinusi, Vladimir
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<br/>Abstract: Not Available
Tue, 10 Feb 2015 09:50:54 GMT

Kepler's Problem in Rotating Reference Frames Part I: Prime Integrals, Vectorial Regularization
http://hdl.handle.net/2268/178158
Title: Kepler's Problem in Rotating Reference Frames Part I: Prime Integrals, Vectorial Regularization
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<br/>Author, coauthor: Condurache, Daniel; Martinusi, Vladimir
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<br/>Abstract: Not Available
Tue, 10 Feb 2015 09:49:36 GMT

Relative Spacecraft Motion in a Central Force Field
http://hdl.handle.net/2268/178157
Title: Relative Spacecraft Motion in a Central Force Field
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<br/>Author, coauthor: Condurache, Daniel; Martinusi, Vladimir
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<br/>Abstract: Not Available
Tue, 10 Feb 2015 09:46:30 GMT

Exact solution to the relative orbital motion in eccentric orbits
http://hdl.handle.net/2268/178155
Title: Exact solution to the relative orbital motion in eccentric orbits
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<br/>Author, coauthor: Condurache, Daniel; Martinusi, Vladimir
<br/>
<br/>Abstract: This paper studies the relative orbital motion between arbitrary Keplerian trajectories. A closedform vectorial solution to the nonlinear initial value problem that models this type of motion with respect to a noninertial reference frame is offered. Without imposing any particular conditions on the leader or the deputy satellites trajectories, exact expressions for the relative law of motion and relative velocity are obtained in a closed form. This solution allows the parameterization of the relative motion manifold and offers new methods to study its geometrical and topological properties. The result presented in this paper opens the way to obtain new classes of approximate solutions to the equations of relative motion with time, an eccentric or true anomaly as independent variables.
Tue, 10 Feb 2015 09:43:02 GMT

Vectorial Regularization and Temporal Means in Keplerian Motion
http://hdl.handle.net/2268/178153
Title: Vectorial Regularization and Temporal Means in Keplerian Motion
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<br/>Author, coauthor: Condurache, Daniel; Martinusi, Vladimir
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<br/>Abstract: Not Available
Tue, 10 Feb 2015 09:36:03 GMT