729 research outputs found
Replication Data for: Robust Design Optimization of Expensive Stochastic Simulators Under Lack-of-Knowledge
No full textThis dataset contains the numerical model of a crashbox (LS-DYNA key file). The dataset includes a python script that can be used to manipulate the parameters t1, t2, and tsw as described in the paper. In addition, a python script is included to model spatial uncertainty of adjacent components as was proposed in an earlier publication. A read me file in included that contains an example and more details. Solving the numerical model requires an active LS-DYNA license
Interval fields on FE model input data and on displacement output patterns in static FE-analysis
No full textThis paper discusses the application of interval fields for the analysis of uncertain mechanical structures. More specifically, this work illustrates the use of interval fields to represent uncertainties with spatially distributed uncertain parameters in the context of finite element analysis. The methods to represent a spatial uncertainty by interval fields both at the input and the output side of a static finite element analysis are combined in this paper. At the input side, the concept of interval fields is applied to represent a spatial uncertainty with an interval correlation length. At the output side, the uncertain displacements are represented with an interval field. The complete method from interval field representation of the input to interval field representation of the output is detailed and the application of the complete methodology is illustrated using a numerical example. © (2012) by the Katholieke Universiteit Leuven Department of Mechanical Engineering All rights reserved.status: Publishe
[Code] 1DRTESolv: One dimensional RTE solver for gray medium
No full textThis analytical solver calculates the radiative transfer in plane-parallel gray medium bound by two gray walls. The solution procedure is discussed in detail in Chapter 14 of “Radiative Heat Transfer” (3rd Edition) by Michael Modest.
CRediT Statement: Mika, Moens, and Nevarez (alphabetically listed) were the main developers and contributed equally in the coding and documentation. David contributed to an earlier version of the code and developed test cases. Povinelli supervised the software development. Roy provided theoretical support and supervised the overall project.
Current Version: v1-alph
High dimensional dependence via pair constructions for interval finite models
No full text© Proceedings of ISMA 2018 - International Conference on Noise and Vibration Engineering and USD 2018 - International Conference on Uncertainty in Structural Dynamics. All rights reserved. Classical (independent) interval analysis considers a hyper-cubic input space consisting of independent intervals. This stems from the inability of intervals to model dependence and might result in a serious over-conservatism as no physical guarantee of independence of these parameters exists. In a spatial context, dependence of one model parameter over the model domain is usually modelled using a series expansion over a set of basis functions that interpolate a set of globally defined intervals to local (coupled) uncertainty. However, such approach might prove to be too inflexible to model the dependence between a large number of model parameters. This paper therefore presents a flexible approach for the modelling of dependent intervals that is also applicable to high-dimensional problems. Specifically, it is proposed to construct the dependence structure in a similar approach to copula pair constructions, yielding a limited set of 2-dimensional dependence functions. The applied case studies indicate the flexibility and performance of the method.status: Published onlin
The interval finite element method for static structural analysis
No full textThis paper focuses on possible solution strategies for the interval finite element method (IFEM) for mechanical structures with uncertain parameters. Particularly the static IFEM analysis is discussed, which was inspired from the fuzzy finite element method (FEM) for dynamic analysis developed by Moens [1]. For an implementation of the IFEM for statics, different solution strategies based on interval arithmetics, optimisation and vertex analysis were developed and tested. © 2005 Elsevier Ltd.status: Publishe
A twin-mesh approach for random field analysis in high-dimensional dynamic models
No full textNon-deterministic methods such as the random field approach suffer from the curse of dimensionality from computational burden of industrially sized models. The computational complexity increases at high dimensions due to increased time complexity of eigenvalue computations, leading to the Karhunen-Loéve series expansion becoming intractable. This makes the corresponding propagation routines to become inviable. A novel methodology is proposed for efficient propagation of a random field by tackling this problem from the discretization perspective. The method uses a twin-model that efficiently discretizes a random field on a coarse mesh grid using a KL expansion, which is then propagated on a high-dimensional grid of the Finite Element model. A two-dimensional model of moderate-dimensionality with 10000 elements is used to illustrate the numerical efficiency of this approach through a convergence study focusing on the resolution of the twin-model when applied in a dynamic analysis. The method is also well suited for higher dimensions.sponsorship: The authors would like to acknowledge support of the Flemish Research Foundation (FWO) in the framework of the project "HiDIF: High Dimensional Interval Fields" (project number G0C2218N). (Flemish Research Foundation (FWO)|G0C2218N)status: Published onlin
Bayesian estimation of interval bounds based on limited data
No full text© Proceedings of ISMA 2018 - International Conference on Noise and Vibration Engineering and USD 2018 - International Conference on Uncertainty in Structural Dynamics. All rights reserved. When conducting uncertainty quantification, probability methods are widely used to represent quantities of a variable nature. First, a type of probability density function has to be chosen, often based on initial assumptions and physical boundary conditions, defining a set of stochastically parameters. Because the available data is physically limited to a finite number, there will always be uncertainty on the exact value of these parameters. At some point, the amount of experiments will be too low for the estimated parameters to be of practical use. In the case of very low data availability, one can attempt to use intervals instead to quantify the variability. Because no probability density function is defined, intervals can be used in the presence of low data availability, leaving only an upper and lower bound to be defined. This paper will present a method to estimate interval bounds based on a limited set of experiments, trying to optimally use the information they contain and determine practically usable interval bounds.sponsorship: The KU Leuven fund and the FWO fund for scientific research are hereby graciously acknowledges. (KU Leuven fund, FWO fund)status: Publishe
Local interval fields for spatial inhomogeneous uncertainty modelling in structural dynamics
No full textsponsorship: The authors would like to acknowledge the financial support of the Flemish research foundation in the framework of the research project G0C2218N and the postdoctoral grant 12P359N of Matthias Faes. (Flemish research foundation|G0C2218N, Flemish research foundation|12P359N)status: Published onlin
‘Moet toch je eigen profijt betrachten, kerel!’: Invloeden van het naoorlogse activisme op Felix de Boeck
No full text‘Dit is onzen Felix’, stond er onder het paginagrote portret van de boer en kunstenaar Felix de Boeck in het katholieke tijdschrift Pogen. Het portret, een linosnede gemaakt door Prosper de Troyer, toonde een ferme kunstenaar met brede armen en een volle baard. De Boeck was bij publicatie van het artikel niet op de hoogte van de inhoud van het stuk. Uit het bijbehorende artikel van Wies Moens werd snel duidelijk van wie ‘onzen Felix’ eigenlijk was: Moens wilde De Boeck opnemen in zijn humanitair-expressionistische kamp. In dat streven vond Moens echter een kaper op de kust, in de persoon van Jozef Peeters
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