| Unidirectional fiber reinforced composites are commonly used in aerospace structural applications, such as engine nacelles and helicopter blades, as well as in wind turbine blades. These large, complex structures commonly contain fiber wrinkles caused by gathering and kinking of fibers in the curing process. The presence of fiber wrinkle defects can significantly compromise strength, stiffness, and delamination resistance, and thus reduce the anticipated structural performance. While some techniques have been established to find the effective stiffness of a section of material containing certain types of fiber wrinkles, there is no general approach to model the effects of an arbitrary fiber wrinkle profile. In this research project, a finite element analysis technique capable of modeling a wrinkle with an arbitrary configuration in a unidirectional fiber reinforced composites was developed. The finite element technique was then employed to model the tensile response of unidirectional glass/epoxy composite coupons with a fiber wrinkle of various configurations. The finite element results were compared with experiments. Good agreement was obtained in terms of the overall stiffness response. |
