Browsing by Author "Attaf, B."

Now showing 1 - 4 of 4

Eco-casting Of Aeolian Blades And Solar Panels With Composites Materials Via Rtm Technology
(University of Eloued جامعة الوادي, 2010-01-01) Attaf, B.
The technique used for manufacturing composite wind turbine blades and solar panels must be sure of environment-friendly. In order to achieve this objective, the closed mould manufacturing process that takes into account environment preservation and health protection besides assurance quality will be the subject of this article. The requirements of sustainable development and ecodesign are the objectives to be fulfilled with an acceptable degree of tolerance in relation to the new regulations and eco-standards.
Eco-technique Of Sewer Renovation Using Composite Shells: Structural Analysis
(University of Eloued جامعة الوادي, 2011-07-01) Attaf, B.
An eco-technical renovation of the sewage system is developed in this paper; this technique involves incorporating into the existing sewer a series of jointed prefabricated sandwich or composite shells. The purpose of his study is to determine the structural shell deflection, the high displacement areas and to validate the non-failure criterion for each ply constituting the inner and outer laminate facings. The numerical results were obtained at low cost by using the finite element method. Studies have focused on structural analysis of a typical shell unit with an ovoid form (egg-shaped section) when it is subjected, during annular space filling operation, to pressure forces generated by wet concrete. To ensure the safety of the composite shell structure, Tsai-Hill criterion function is applied and results are presented for the most stressed plies.
Ecodesign Criteria For Composite Materials And Products
(University of Eloued جامعة الوادي, 2013-01-01) Attaf, B.
According to sustainable development principles, the design of a composite product must be in compliance with the new regulations and standards in terms of Health protection (H) and Environmental preservation (E) besides Quality assurance (Q). With this argument as an objective, our contribution aims to innovate and develop new methodologies providing sustainable design of new generation of composite products through the consideration of the three balanced key aspects: H, E and Q. To achieve these requirements, we have defined and developed new criteria in the form of eco-coefficients, which can later on be implemented into mechanical characterization tests, in advanced composite formulations and associated constitutive equations. They can also be integrated into future finite-element computer programs to assess and improve the performance of the H-E-Q interrelated function.
Effects Of Geometric Ratios And Fibre Orientation On The Natural Frequencies Of Laminated Composite Plates
(University of Eloued جامعة الوادي, 2010-07-01) Attaf, B.; Bachene, M.
The present investigation aims to examine the influence of geometric ratios and fibre orientation on the natural frequencies of fibre-reinforced laminated composite plates using finite element method based on Yang’s theory and his collaborators. The transverse shear and rotatory inertia effects were taken into consideration in the developed Fortran computer program. It has been shown that the use of first-order displacement field provides the same accuracy as higher-order displacement field when the number of elements representing the plate structure is increased (refined mesh). However, poor precision may appear for plates with high thickness-to-side ratio h/a (thickness/side length). This discrepancy limits the application of the developed theory to thick plates (h/a<0.5). The various curves show the evolution of the dimensionless frequency (*) versus fibre orientation angle () and illustrate the apparition of a “triple-point” phenomenon engendered by the increase of the plate aspect ratio a/b (length/width) for a specific value of h/a. This point defines the maximum natural frequency and the associated fibre orientation. Also, results show that for high and/or low aspect ratios, the triple-point phenomenon does not occur. This latter is rapidly reached for thick plates than thin plates when the plate aspect ratio a/b is progressively increased.