ABSTRACT
The tempting performances of the composites involve day by
day, their integration in the realization and the optimization of the
industrial works, aeronautics, car, architecture, civil engineer and sport.
Once integrated in a structure in the form of beam, plate or hull, these
composites undergo dynamic behaviors in particular transverse vibrations of
inflection. For the originator, this behavior must be predicted and guaranteed
during the design, by a good modeling of displacements of the points of the
structure. Also, with the LMP, the LAMMA and the Mechanical engineer of the
ENSET of Douala, the composites are done developed, but a true behavior in
modeling is not carried out yet in particular the vibratory aspect. It is the
reasons for which, we undertook these works relating to « the
study of the behavior of the arrow of a composite material in mechanical
vibration and simulation under Matlab ».
In front of the multidisciplinary requests, we restricted the
study with composite structures of standard folds one-way with 0° or
90° and laminated symmetrical crusader [0/90]s or antisymmetric vibrating
and requested in pure inflection. The main aim pursued during this research is
to predict the behavior of the arrow of an orthotropic structure reinforced by
vegetable local fiber. For that purpose, of the studies analytical and digital
were carried out. The analytical resolution made by means of the methods of
separations of the variables, then of Rayleigh-Ritz of the transverse equation
of motion expressed by the TCS formulated on the model of the plates of
Coils-Kirchhoff then, wide on the model of the beams of Euler-Bernoulli enabled
us to obtain the equations of behavior of the arrow of various structures with
various boundary conditions. Digital modeling was initially the subject, with
simulation under Matlab while introducing with the equations of the arrow
formulated analytically, the parameters of a composite with matrix polyester,
reinforced by fiber of Rhecktophyllum camerunense (RC), then, on the
digital simulation by finite elements under Abaqus of the same composite and
finally on the setting-up of the software i-VAC which makes it possible to
predict the behavior of the arrow of the composites studied within the
framework of this work.
The results of the digital simulation under Matlab agree with
an average variation relative of 0.026625% to the results of simulation under
Abaqus and with an average variation relative of 0.6% to the results of an
experimental study drawn from the literature. In addition, it was established
that, to reduce the arrow of a structure, it is necessary to choose elements
reduce length, higher or equal to height 15 mm (beams), with a rate of fibers
equal to or higher than 35% of average longitudinal modulus Young equal to or
higher than 8.5 GPa.
V
Keys Words : Composites materials ; Arrow ;
Mechanical vibration ; Inflexion.
vi
TABLE DES MATIERES
DEDICACE . ii
REMERCIEMENTS iii
RESUME . iv
ABSTRACT . v
TABLE DES MATIERES vi
LISTE DES FIGURES x
LISTES DES TABLEAUX xii
LISTES DES SYMBOLES ET ABREVIATIONS xiii
INTRODUCTION GENERALE 1
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