ORBi Open Repository and Bibliography
In may 2007, the ULg's Administrative Board (joined in June 2007 by the FUSAGx) decided to create an institutional repository and defined a strong institutional self-archiving policy to increase the visibility, accessibility and impact of the University's publications (Board's decision).
This decision led to the official launch, in November 2008, of the ORBi platform including both the Academic Bibliography and the Institutional Repository of the Wallonia-Europe University Academy.
Bridging the gap between Nonlinear Normal Modes and Modal Derivatives - Sombroek, Cees; Renson, Ludovic; Tiso, Paolo; Kerschen, Gaëtan
Nonlinear Normal Modes (NNMs) have a clear conceptual relation to the classical linear normal modes (LNMs), yet they offer a solid theoretical framework for interpreting a wide class of non-linear dynamical phenomena with no linear counterpart. The main difficulty associated with NNMs is that their calculation for large-scale models is expensive, particularly for distributed nonlinearities. Repeated direct time integrations need to be carried out together with extensive sensitivity analysis to reproduce the frequency-energy dependence of the modes of interest.
In the present paper, NNMs are computed from a reduced model obtained using a quadratic transformation comprising LNMs and Modal Derivatives (MDs)....
Magnetic screening with bulk high-temperature superconducting hollow tubes in the “emission” configuration - Vanderbemden, Philippe; Hogan, Kevin; Wera, Laurent; Vanderheyden, Benoît; Fagnard, Jean-François
Due to their unique ability to trap magnetic fields exceeding the saturation limit of
conventional ferromagnetic materials, bulk superconductors can be used successfully in
motors and generators. In several topologies however, the stray magnetic field produced by
the superconducting magnet or coils needs to be strongly reduced outside the device. The
screening can be performed using either active or passive magnetic screens. In this respect, a
hollow tube made of bulk high temperature superconducting (HTS) material provides a strong
attenuation of external low frequency magnetic fields and acts as a very efficient passive
screen. The situation where the stray magnetic field generated by an electromagnetic device
Simplified analytical methods for the crashworthiness and the seismic design of lock gates - Buldgen, Loïc
The PhD dissertation aims to provide simplified tools based on analytical formulations in order to ease the pre-design of lock gates. The first part of the thesis is devoted to ship collisions. The resistance of the impacted gate is evaluated by combining global and local deforming modes. In the second part of the dissertation, an analytical solution is proposed to estimate the total hydrodynamic pressure acting on a lock gate during a seism, with due consideration for the fluid-structure coupling. Numerical validations are proposed for both ship collisions and earthquakes.
Multi-Domain Approaches for the Solution of High-Frequency Time-Harmonic Propagation Problems - Vion, Alexandre
The numerical solution of high-frequency time-harmonic propagation problems by volumic discretization methods is a challenging task, most notably because of the very large size of the resulting linear systems. We present a framework for a class of iterative methods that distribute the work between several CPUs and exchange information between physical or artificial interfaces. The goal is to define subproblems of manageable sizes, and to exploit the power of parallel supercomputers.