In-situ Micro X-ray computed tomography (μCT) offers a new opportunity to monitor the 3D morphology and damage evolution of short carbon fiber-reinforced polymer (SCFRP) composite. However, the sample size of in-situ μCT is generally limited to achieve high revolution, which resulted in different mechanical behavior compared with that obtained from standard samples. In this study, μCT scans with two resolutions were combined to character the 3D geometrical morphology and monitor the 3D deformation fields of SCFRP composites under tension. High resolution μCT scans with voxel size of 0.68 μm were used to quantify the geometric characteristics of fibers and void defects inside small samples. Low resolution in-situ μCT scans with voxel size of 4 μm and digital volume correlation method were utilized to monitor the 3D deformation fields of standard specimens under tension. The failure behavior of SCFRP was determined by the micro geometric morphology. The fracture surface under tension is oriented along 120^o and 240^o in the XY plane, which is consistent with the fiber and debonding distribution.

原位微X射线计算机断层扫描（μCT）提供了一个新的机会来监控短碳纤维增强聚合物（SCFRP）复合材料的3D形态和损伤演变。但是，原位μCT的样品大小通常受到限制，无法实现高转速，因此与从标准样品获得的力学行为相比，机械性能有所不同。在这项研究中，将具有两种分辨率的μCT扫描组合以表征3D几何形态并监测SCFRP复合材料在张力下的3D变形场。体素尺寸为0.68μm的高分辨率μCT扫描用于量化小样品内部纤维和空隙缺陷的几何特征。低分辨率原位使用体素大小为4μm的μCT扫描和数字体积相关方法来监控标准样品在张力下的3D变形场。SCFRP的失效行为由微观几何形态决定。处于拉伸状态的断裂面在XY平面中沿120 ^o和240 ^o定向，这与纤维和脱粘分布一致。