Analysis of the Geometry and Microcracks of Kevlar/Epoxy Composites

Abstract

This paper is concerned with the evaluation of the parameters of plain weave textile from Kevlar 49 fibers. They were determined following the basic parameters of the textiles e.g. crimp length, crimp amplitude, thickness of the woven fabric, dimensions of the cross-sectional tow (tow width, tow height) and crimp angle. The number of fibers in the warp and tow strands was also determined.The work is also concerned with the analysis of microcracks in the material, that is, microcracks that appeared after the tensile test. Microscopic observation of cracks occurred on the test specimen strip according to DIN EN ISO 14129 for tensile testing. Strips of the material were cut, the metallurgical methods used being kept perpendicular to the thickness of the test specimen. Microcracks occurred in the individual planes located in the chosen reference axis. Microcracks were detected in the entire width of the specimen. The types of microcracks were determined by the length and traits of the microcracks.