ParisTech

About: ParisTech is a education organization based out in Paris, France. It is known for research contribution in the topics: Finite element method & Residual stress. The organization has 1888 authors who have published 1965 publications receiving 55532 citations. The organization is also known as: Paris Institute of Technology & ParisTech Développement.

Effect on drag of the flow orientation at the base separation of a simplified blunt road vehicle

Abstract: The separated flow past the square-back model used in the experiments of Ahmed et al. (1984) is controlled using flaps at the end of the top and bottom faces. A parametric study of the flow regarding the slant angle of the flaps is performed from pressure and force measurements as well as particle image velocimetry. When the bottom flap orientation is fixed, variations in the top slant angle indicate a quadratic dependence of drag versus lift. This relationship presents self-similarities when modifying the bottom flap angle. It is furthermore observed that the lift is an affine function of both slant angles and the drag is a second-order polynomial containing a coupling term between the two angles. The evolution of the drag, depending on both angles, is discussed. The contribution of the wake size, lift-induced drag as well as the local drag induced by the inclination of the flaps is interpreted.

Shape memory effect and properties memory effect of polyurethane

Abstract: The relationship between shape and properties memory effect, especially viscoelastic properties of polyurethane under study is the main aim of this research work. Tensile tests have been performed in order to introduce 100% of deformation in the pol- yurethane samples. Under this deformation, stress-relaxation experiments have been performed in order to eliminate the residual stresses. This deformation of the samples has been fixed by cooling. Recovery tests, then, were carried out at different isothermal tem- peratures that varied from 30 � Ct o 60 � C. Viscoelastic behavior has been studied by a biparabolic model and by using the Cole-Cole method. It was shown that this model describes the behavior of the polymer at the different states of shape memory tests. The con- stants of this model then have been determined. This study leads to a better understanding of the mechanism of shape memory effect. The comparison between the virgin polymer and the polymer after a recovery test by DMTA (dynamic mechanical thermal analysis) and by Cole-Cole method has illustrated that the polymer does not obtain its initial properties even when it was totally regained its initial shape. These results have been confirmed by three successive shape memory tests on the same sample and by com- paring the mechanical characteristics of different cycles because ''shape memory effect'' and ''properties memory effect'' do not follow the same mechanisms. V C 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 000: 000-000, 2012

A multi-objective optimization model for hub network design under uncertainty: An inexact rough-interval fuzzy approach

Abstract: This article proposes a multi-objective mixed-integer model to optimize the location of hubs within a hub network design problem under uncertainty. The considered objectives include minimizing the maximum accumulated travel time, minimizing the total costs including transportation, fuel consumption and greenhouse emissions costs, and finally maximizing the minimum service reliability. In the proposed model, it is assumed that for connecting two nodes, there are several types of arc in which their capacity, transportation mode, travel time, and transportation and construction costs are different. Moreover, in this model, determining the capacity of the hubs is part of the decision-making procedure and balancing requirements are imposed on the network. To solve the model, a hybrid solution approach is utilized based on inexact programming, interval-valued fuzzy programming and rough interval programming. Furthermore, a hybrid multi-objective metaheuristic algorithm, namely multi-objective invasive weed opti...

Quality of collaboration in design meetings: methodological reflexions

Abstract: This paper provides a critical appraisal of methods for analysing the quality of collaboration in design meetings. After a discussion of how effective collaboration can be related to successful design, some existing approaches to evaluating the quality of collaboration are reviewed, and one specific method for analysing and evaluating socio-cognitive processes involved in design meetings is presented in some detail, together with its strengths and weaknesses. The concluding discussion aims to deepen and extend previous methods, with a view to outlining future research perspectives. The need for taking into account the additional dimension of the dynamics of interpersonal relations, involving the mutual regulation of tensions and affects, is discussed. It is argued that there is no privileged standpoint from which to evaluate the quality of collaboration: the qualities to which precedence will be given depend on the objects of co-design activities, what is at stake, and the alternative viewpoints of social...