الفهرس 
General IntroductionOnly 14 pages are availabe for public view
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Abstract
The main task of this article is using two and multiple beam interfereometric techniques to determine the optical, geometrical, and opto-mechanical properties of stretched fibres. In chapter (1), a general introduction and pervious work on the characterization of fibres are given. In chapter (2), the description of the set- up and the theoretical considerations of these techniques are given. The basic concepts of automatic fringe pattern analysis for multiple beam Fizeau fringes in transmission are also given. The concepts of mechanical properties of fibres with their theoretical models are discussed in this chapter. In chapter (3), a novel video opto-mechanical (VOM) device is designed. The effect of stretching speed on the optical and structural properties of polypropylene fibres during the dynamic stretching process is studied. The refractive indices, birefringence, transverse sectional area and the orientation function of PP fibres are studied as a function of the draw ratio at different speeds of stretching. Stretching process of PP fibre with low speed (slow stretching) is recommended to overcome the necking deformation along the fibre. In chapter (4), During the cold- drawing process an initial undrawn material is transformed into anisotropic one across a narrow transition region called ‘neck’. A sample of PP fibre is stretched to have a neck at room temperature. The optical properties of the deformed material over the necking region are examined. The effect of necking on the optical properties of the fibre is confirmed by the determination of the 3D refractive index profile at different regions along the deformed PP fibre. The conformation between our obtained structure results and Rudnev`s et al. interpretation is discussed. In chapter (5), interferometric investigation of the neck propagation phenomenon of stretched fibre is carried out using automatic multiple- beam Fizeau fringes technique. It is observed that under such a deformation regime a neck is likely to form and propagate steadily towards the gripped ends of the stretched sample. The 3D time- refractive index profile is suggested also to clarify the fixed profile during propagation of necking. The speed of neck propagation is calculated and its dependence on the speed of drawing and draw ratio is investigated. In chapter (6), a dynamic method is suggested to determine the variation of both refractive index and transverse sectional area of fibres during the dynamic cold drawing process. The suggested method depends on the physical principle of constant volume of the filament during the cold drawing process.