Deflection of Rectangular Laminated Composite Plates using Dynamic Relaxation Method

(osama mohammed elmardi suleiman khayal) #1

I am grateful and deeply indebted to Professor Mahmoud Yassin Osman for
close supervision, constructive criticism, and provision of useful parts of his papers
and/or other relevant materials during his stay in china, and also the valuable
recommendations during the various stages of building up the present book, without
which this work would not have been accomplished.
I am also indebted to many people. Published texts in mechanics of materials,
numerical techniques analysis have been contributed to the author’s thinking.
Members of mechanical engineering department at Nile Valley University, Red Sea
University, Sudan University of Science and Technology and Blue Nile University
have served to sharpen and refine the treatment of my topics. The author is extremely
grateful to them for constructive criticisms and suggestions.
Special appreciation is due to the British Council’s Library for its quick
response in ordering the requested reviews and papers.
Also thanks are extended to the Faculty of Engineering and Technology,
Atbara for enabling me to utilize its facilities in accessing the internet and printing
out some papers, reviews and conference minutes concerning the present book.
Special gratitude is due to associate Professor Mohamed Ibrahim Shukri for
the valuable gift 'How to write a research ’ which assisted a lot in writing sequentially
the present book. Thanks are also due to Associate Professor Izz Eldin Ahmed
Abdullah for helping with the internet.
Thanks are also due to Faculty of engineering and technology, Nile Valley
University administration for funding this research in spite of its financial hardships.
A Dynamic relaxation (DR) program based on finite differences has been
developed for small and large deflection analysis of rectangular laminated plates
using first order shear deformation theory (FSDT). The displacements are assumed
linear through the thickness of the plate. Dynamic Relaxation (DR) method is
presented for the geometrically linear and nonlinear laterally loaded, rectangular
laminated plates. The analysis uses the Mindlin plate theory with first order shear
deformation theory (FSDT) which accounts for transverse shear deformation. A
computer program has been compiled using a FORTRAN program. The convergence
and accuracy of the DR solutions for elastic small and large deflection response are
established by comparison with various exact and approximate solutions. New
numerical results are generated for uniformly loaded square laminated plates which
serve to quantify the effects of shear deformation, material anisotropy, fiber
orientation, and coupling between bending and stretching.
It was found that linear analysis seriously over-predicts deflections of plates.
The shear deflection depends greatly on a number of factors such as length/ thickness
ratio, degree of anisotropy and number of layers. It was also found that coupling
between bending and stretching can increase or decrease the bending stiffness of a
laminate depending on whether it is positive or negative.
It was also found that: The convergence and accuracy of the DR solution is
dependent on several factors including boundary conditions, mesh size and type,
fictitious densities, damping coefficients, time increment and applied load. Also, the
DR large deflection program using uniform finite differences meshes can be
employed in the analysis of different thicknesses for isotropic, orthotropic or
laminated plates under uniform loads. All the comparison results for simply
supported (SS4) edge conditions showed that deflection is almost dependent on the
direction of the applied load or the arrangement of the layersDeflection of Rectangular Laminated Composite Plates using Dynamic Relaxation Method.pdf (1.7% u)

(عمارة إسلامية) #2

بسم الله الرحمن الرحيم
السلام عليكم ورحمة الله وبركاته
جزاكم الله تعالى خيرًا أخي د. أسامة؛
على طيب ما تودعون في القسم خاصّة.
جعله الله تعالى في ميزان حسناتكم، وزادكم من فضله.

(osama mohammed elmardi suleiman khayal) #3

thanks very much