Salah H.B.H.,Laboratoire Of Mecanique Of Sousse |
Daly H.B.,Laboratoire Of Mecanique Of Sousse |
Denault J.,Industrial Materials Institute of Canada |
Perrin F.,Industrial Materials Institute of Canada
Polymer Engineering and Science | Year: 2013
Polypropylene (PP) clay nanocomposites were injection-molded using two different coupling agents based on maleic anhydride-grafted PP (MA-g-PP) and two clay loadings. The morphological aspects of these materials were studied by depth profiling. Molecular chain and clay orientations were characterized using attenuated total reflectance-infrared analysis and transmission electron microscopy (TEM). Both clay platelets and PP molecular chain orientations were found to decrease from the surface toward the core of the injection-molded specimens. Clay intercalation, characterized by both complementary X-ray diffraction and TEM, was found to be significantly influenced by both the characteristics of the coupling agent used and the type of residual stresses generated at each layer across the thickness of the injection-molded parts. The use of low-molecular weight (Mw) MA-g-PP led to a uniform intercalation but with no further exfoliation. The use of higher molecular weight MA-g-PP led to a heterogeneous intercalation with some signs of exfoliation. The crystallization behavior of PP clay nanocomposites studied by differential scanning calorimetry showed an increase in the level of crystallinity from the surface to the core of the specimens; these results were also confirmed by scanning electron microscopy. Copyright © 2012 Society of Plastics Engineers.
Zaghdoudi M.,Laboratoire Of Mecanique Of Sousse |
Albouy P.-A.,University Paris - Sud |
Tourki Z.,Laboratoire Of Mecanique Of Sousse |
Vieyres A.,Solvay Group |
Sotta P.,Solvay Group
Journal of Polymer Science, Part B: Polymer Physics | Year: 2015
X-ray diffraction technique is used to evaluate the evolution of the segmental orientation in a natural rubber sample during mechanical uniaxial stretching and in the Gaussian regime condition. The method proves to be sensitive enough for testing the validity of the stress-optical law. Measurements are performed at different temperatures and show that the dependence of the orientation parameter upon elongation is very close to the prediction of classical phantom theories. On the contrary, a significant Mooney-Rivlin correction is needed to account for the stress-strain relation. Consequently, systematic deviations from the stress-optical law are observed, in particular for elongations below 2. These deviations are adverse from predictions of both the constrained and the diffuse junction theories. © 2015 Wiley Periodicals, Inc.
Chaker A.,Teleport |
Chaker A.,Laboratoire Of Mecanique Of Sousse |
Laribi M.A.,Teleport |
Zeghloul S.,Teleport |
Romdhane L.,Laboratoire Of Mecanique Of Sousse
IECON Proceedings (Industrial Electronics Conference) | Year: 2011
This paper deals with the design and analysis of a spherical parallel mechanism (SPM) to be used as a haptic device for a medical application. The chosen application is mini invasive surgery during which an anastomosis technique has to be performed. First, the task space, necessary to perform an anastomosis technique, which consists in suturing two parts of a ruptured hollow organ, was determined using a motion capture system. An experimented surgeon was asked to perform the anastomosis technique on a simulator. Several markers were used to track the motion of the hand-tool system during the operation. The experimental data were used to identify the necessary workspace for performing this operation. Then, a spherical parallel manipulator was designed, which has a workspace containing the desired workspace. An optimization procedure was carried out to find the optimal spherical manipulator with the closest workspace to the desired one. Genetic Algorithms were used to solve this problem. The effect of the rotation range around the tool axis on the structure parameters and workspace is also discussed. Finally, the obtained design parameters were shown, through simulation, to yield the required workspace. © 2011 IEEE.