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Oudjene M.,CNRS Wood Materials Research Laboratory | Meghlat E.-M.,Mouloud Mammeri University | Ait-Aider H.,Mouloud Mammeri University | Batoz J.-L.,Center Pierre Guillaumat 2
Composite Structures | Year: 2013

This paper discusses a numerical approach, based on beam-to-solid modelling, for the simulation of the nonlinear structural behaviour of timber-to-concrete composite beams made with screws. The present contribution is an alternative to the detailed 3D modelling of the screws using solid elements and simplified approaches which use spring elements at each screw location. The screws were modelled using one-dimensional beam element, while the timber and concrete members were modelled, in detail, using 3D solid elements. To deal with the coupling between the common nodes, the 4-node beam element with only translational degrees of freedom (d.o.f.) per node, recently developed by the authors [1,2], has been extended to nonlinear analysis and employed to model the screws, since the existing 2-node beam element is obviously not fulfilled for screws in timber [2]. The effectiveness of the numerical model developed was verified experimentally showing several advantages by comparison to the existing models in the literature. © 2013 Elsevier Ltd. Source


Meghlat E.-M.,Mouloud Mammeri University | Oudjene M.,CNRS Wood Materials Research Laboratory | Ait-Aider H.,Mouloud Mammeri University | Batoz J.-L.,Center Pierre Guillaumat 2
Construction and Building Materials | Year: 2013

This paper presents a novel way to simulate the behaviour of nailed and screwed timber joints, using the finite element method. In order to avoid the detailed 3D modelling of nails (or screws) using solid elements, which is costly ineffective, the authors proposed and developed an approach based on beam-to-solid coupling where the nails (or screws) were modelled using one-dimensional beam element, while the assembled timber members were modelled using solid elements. To deal with the coupling between the degrees of freedom (d.o.f.) belonging to the screws and those belonging to the timber, the existing 2-node beam element has been modified involving in a 4-node beam element with only translational d.o.f. per node, leading in fact to a full compatibility with solid elements. Using the numerical approach developed, the linear elastic behaviour of a push-out shear test of a single shear timber-to-timber connection was successfully simulated.©2012 Elsevier Ltd. All rights reserved. Source


Meghlat E.-M.,Mouloud Mammeri University | Oudjene M.,CNRS Wood Materials Research Laboratory | Ait-Aider H.,Mouloud Mammeri University | Batoz J.-L.,Center Pierre Guillaumat 2
ECCOMAS 2012 - European Congress on Computational Methods in Applied Sciences and Engineering, e-Book Full Papers | Year: 2012

Previous works by the authors [1,2] highlighted that screwed and nailed timber connections can be efficiently modeled using beam-to-solid model. In these studies, the screws were modeled using one-dimensional beam element, based on the Euler-Bernoulli beam theory, and the timber members using 2D 4-node plane stress elements. It is recognized that in a general connection with arbitrary combinations of materials and nails, the FE analysis is the best approach to investigate the behaviour of the connection. However, 3D models currently available to predict the behaviour of such connections mainly rely on the detailed 3D modeling of the screw (or nail), using 3D solid elements, which have been proven costly ineffective. Although beam-to-solid modeling was found adequate and fast for the description of the behaviour of the connection, combining beam element with solid element needs to take into account the contribution of the solid element to the rotation of the section of the beam, since the degrees of freedom (d.o.f) differ from one element to another. This is referred to as coupling multipoint constraint equations, which are comprehensively discussed in the literature [3]. The modeling of nailed connections is not the focus of the present paper. The authors would like to show how an existing 2-node beam element can be modified to deal with beam-to-solid coupling with naturally less coupling constraint equations. Thus, a one-dimensional 4-node beam element with only translational d.o.f., based on the Tomoshenko's beam theory, was formulated and successfully implemented in the ABAQUS finite element software, via a UEL user subroutine. This paper is devoted to the formulation and the numerical validation aspects. The results obtained showed accurate analyzes. Source


Beckers B.,Compiegne University of Technology | Beckers B.,Center Pierre Guillaumat 2 | Masset L.,University of Liege | Beckers P.,University of Liege
CAD Computer Aided Design | Year: 2011

For many years, important efforts have been devoted to efficiently compute the view factors in the frame of radiative heat exchanges. This subject has also received special attention in the more recent development of global illumination methods. Basically two techniques are available; the first one is based on projections and the second one on ray tracing methods. Here we will present a new algorithm dealing with projections and show that we can solve both the problems of computing view factors and solid angles by using the same projection. The proposed method is precise and fast, so it can be used in interactive design software. © 2010 Elsevier Ltd. All rights reserved. Source


Robert C.,University of Lorraine | Robert C.,Arts et Metiers ParisTech | Ayed L.B.,University of Lorraine | Delameziere A.,University of Lorraine | And 2 more authors.
International Journal of Material Forming | Year: 2010

This paper deal with a simplified approach for the contact management between the tool and the sheet in incremental sheet metal forming process. The general principle of this approached is to imposed displacement of the nodes in contact with the tool at a given position. After a description of this method, some numerical aspects of this algorithm are investigated. Applied a pressure contact on the elements of the contact zone have few influence of the results (deformed shape and thickness) but reduce the computational time of the simulation. The size of tool displacement is also investigated. Using increments of the tool diameter give a good accuracy of the thickness and of the geometry. Large increments do not affect the predicted geometry, but only the minimal thickness of the forming component is accurate. This new algorithm gives a good reduction of the computational time compared with a standard contact algorithm (from a ratio of 0.75 to 0.18, depending of the increment size). © 2010 Springer-Verlag France. Source

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