DescriptionKevlar has a remarkable combination of high strength, high modulus, toughness and thermal stability compared to many other organic fibers. These impressive properties are due to their molecular structure, developed during their production process which is based on liquid crystal technology, as the rigid molecular chains form a mesophase in solution. Modeling of the high-performance ballistic fabric has gradually shifted from the continuum and yarn length scales to the sub-yarn length scale which enabled establishment of the relationships between the fabric penetration resistance and various fiber-level phenomena such as fiber-fiber friction, fiber twist, and transverse properties of the fibers. An instrumented indentation method was established in this thesis work to accurately measure the local elastic-plastic material properties of a single fiber. As indentation theory assumes that the indent is being placed on a semi-infinite flat surface, general area function cannot predict accurate projected area on a circular specimen. The indentations on cylindrical surface require modified equations to determine the area function and subsequently, the hardness and reduced modulus. The Oliver-Pharr instrumented indentation data analysis method is followed for the calculation of area function of the indenter geometry through the simulation of the known properties of the material. This new area function calculation method is compared with the geometry correction method by Quinn McAllister and John W. Gillespie, Jr to calculate the elastic modulus of the fiber in transverse direction. In addition, Compliance contributions are attributed to the lack of constraint due to the finite geometry of a curved fiber surface. This compliance contribution is accounted by using a proposed area correction to capture the geometry of the curved fiber-probe contact. Implementation of these corrections to experimental indentation curves results in accurate measurements of the fiber elastic modulus.