Mechanics of laminated composite containing marcel defects

Abstract

Marcel is fabrication induced defects in composite materials. Others have used the terms "fiber waviness" or "fiber imperfections" to refer to these manufacturing defects. Marcel defect is shown in Fig.1. It is quantified geometrically by A/L, the ratio of amplitude A to wavelength L. Marcel defects have been observed to occur in, or through the thickness of, the plane of lamination. The present research involves the development of mathematical model and numerical solution methods to investigate the effect of marcel defects on the elastic behavior and stability of composite laminate. A theoretical model is developed for a unidirectional lamina whose fiber is sinusoidal in the plane of the lamina. This model predicts the elastic properties of the lamina and bending stiffness of laminate as function of A/L. Percent reduction of critical buckling load versus A/L is obtained.