Study On The Relation Between The Structure Of Round-section Fibers And Reflection

Luster is an important evaluation standard in fiber quality. The reflection decides luster of fibers. There is an inseparable relation between the reflection and structure.Now, less study on the reflection of single fiber has been done, including surface reflection, transmission light, internal surface reflection. But skin-core structure and the Descartes ray of internal surface reflection haven't been involved. While parallel ray strikes fibers vertically, the internal reflection angle increases to certain value with incident angle, and then decreases. The ray which reflects from the maximum angle is called Descartes ray. Also there is Descartes ray in the proceeding of reflection in round-section fibers. In this article, the relation between three parts of fiber's structure (including skin-core structure, inner structure nonuniformity and surface roughness) and the reflection character is studied.Firstly, from the processing technology of chemical fibers, the cause of skin-core structure, influence factors of inner structure nonuniformity and cause of surface roughness are discussed. A physical model about skin-core structure is built according to the structural character of chemical fibers. With the aid of the internal reflected light's Descartes ray, according to the principle of geometrical optics the influence of the skin thickness and the difference of skin-core structure's refractive index to reflected light are systematically analyzed based on the theory.Designing experimental program, preparing equipment, aiming at the three parts of fiber structure in theoretical analysis, simulation tests are built, which confirms the conclusion of theoretical analysis. In these tests, the intensity distribution of two-dimensional diffuse reflection is tested, and the change law of Descartes ray is analyzed. The experimental results and theoretical analysis correspond excellently with one another.The research perfects the study on Descartes ray of fibers, and enriches the research content about reflection character, which has important academic significance on improvement of character and development of particular fibers.At last, the thesis makes the expectation about the development direction of this research.