Filament winding is a technique to manufacture tubular composite structures and, therefore, is among the most appealing techniques for fabricating critical structures such as hollow tubes. Despite the recent advances, these structures are prone to a varying degree of porosity that may affect their mechanical performance. Therefore, the accurate detection and quantification of the manufacturing porosity is crucial. Micro-CT is most suitable for performing this activity at various scales. This work employs micro-CT for studying porosity inside an as-manufactured filament-winded composite structure. Void characteristics like volume, orientation, size, and relative volume fraction inside the hoop and helical layers are quantified inside a representative curved panel extracted from a glass fiber-vinyl ester tubular composite structure, which has not been studied in detail previously. It was observed that most voids are present in the matrix region. The voids are elliptical rod-like and spherical, with the latter present in the helical layers, which also host the majority of voids and the highest void volume fractions. The voids are highly aligned along the fiber orientation direction with higher misorientations for helical layers than the hoop layer. Large voids in base layers were created due to gaps formed during the winding process. Hence, the main goal of this study is to measure the voids' characteristics and the volumetric fraction during the stacking of filament wound hoop and helical layers during a generic filament winding pattern. The data can be further exploited as input for modeling filament winded composites in the presence of voids by researchers.

纤维缠绕是一种制造管状复合材料结构的技术，因此是制造空心管等关键结构最有吸引力的技术之一。尽管最近取得了进展，但这些结构容易出现不同程度的孔隙率，这可能会影响其机械性能。因此，制造孔隙率的准确检测和量化至关重要。Micro-CT 最适合在各种规模上执行此活动。这项工作采用微型 CT 研究制造的纤维缠绕复合材料结构内部的孔隙率。在从玻璃纤维-乙烯基酯管状复合结构中提取的代表性弯曲面板内量化了环向层和螺旋层内的体积、方向、尺寸和相对体积分数等空隙特征，此前尚未对其进行详细研究。据观察，大多数空隙存在于基体区域中。空隙为椭圆棒状和球形，后者存在于螺旋层中，螺旋层也包含大部分空隙和最高的空隙体积分数。空隙沿着纤维取向方向高度排列，螺旋层的取向差比环箍层更高。由于缠绕过程中形成的间隙，基层中产生了大的空隙。因此，本研究的主要目标是测量在通用长丝缠绕模式中长丝缠绕环和螺旋层堆叠期间的空隙特征和体积分数。研究人员可以进一步利用这些数据作为存在空隙的情况下对长丝缠绕复合材料进行建模的输入。