CFRPの力学特性低下に及ぼす繊維うねりの影響

Abstract

In order to prove the details of reduction of tensile properties in CFRPs by fiber waviness, experimental evaluation has been performed for local strain and stress around fiber waviness in unidirectional composites under tensile loading. Unidirectional composites of continuous fibers with in-plane sinusoidal waviness in a matrix were composed. Strain distributions were measured by using DIC (Digital Image Correlation) method. Stress distributions in fibers on the cross section perpendicular to the tensile loading were evaluated by means of micro-Raman spectroscopy. It was found that longitudinal strain concentration was observed at the inflection point of fiber waviness and transvers strain in tension arose around the top of the wavy fiber. In addition from the stress distribution in fibers across the loading direction less load shearing was observed at the inflection point in the wavy fibers compared with that in straight fibers located next to the wavy fibers.