Correlated rules between complex structure of composite components and manufacturing defects in autoclave molding technology

Based on statistical analysis, considerable defect information obtained by nondestructive identification (NDI) techniques for composite components, different type defects which often form in autoclave molding of composites were summarized, and the effect rules of complex structure in composite components on manufacturing defects were also revealed. Combined with statistical results and defect micrographs, the strong correlation between geometric characteristics (for instance, thickness, gradient of thickness variation, curvature radius) in composite components and controllability of manufacturing defects was discussed in detail. It was found that delamination, pore, void, and rich resin were the four main defects in autoclave molding, and that the ratio of defect appearance was remarkably influenced by complex structure of composite components. Especially, geometric characteristics of composite components had a significant influence on the defect type and defect ratio. For example, too thin or too thick components, too small radius and abrupt change of thickness in components would obviously increase the ratio of defect production. Thickness, curvature radius, and gradient of thickness variation would probably lead to the defects of delamination and void, and gradient of thickness variation would also result in rich resin around the overlap region of long fiber and short fiber in the thickness transition zone.