基于微观尺度X射线断层扫描技术的短切碳纤维SMC复合材料失效分析

Failure analysis of chopped carbon fiber SMC composites by micro X-ray computed tomography

短切碳纤维片状模塑料(SMC)复合材料内部复杂的纤维三维分布及其造成的多样微裂纹演化过程加剧了其失效分析的难度。针对短切碳纤维SMC复合材料的失效行为进行研究,提出采用微观尺度X射线断层扫描技术实时表征材料内部的微观结构,捕捉碳纤维和微裂纹的几何信息,结合先进的图像采集和图像处理技术,进而准确重构出短切碳纤维SMC复合材料在受力过程中的三维结构变化以及微裂纹的完整演变过程,定量测量微裂纹的几何尺寸,实现损伤的精准诊断,并利用Tsai-Wu失效判据和界面开裂后的基体应力场理论等失效方法探究短切碳纤维SMC复合材料的失效机制。该方法的提出对于研究短切碳纤维SMC复合材料的失效过程以及分析相应的失效行为提供了重要依据。

The complex internal three-dimensional fiber distributions and the various microcrack propagation processes of the chopped carbon fiber sheet molding compound(SMC)composites aggravate the difficulty of failure analysis.In-situ micro X-ray computed tomography was proposed in this study to characterize the internal microstructure evolution under different tensile loading conditions.Combined with advanced image acquisition and image processing technologies,the three-dimensional microstructure of the SMC composites,including the complete microcrack propagation,under different loading conditions was reconstructed,where the microcrack geometric size was quantitatively measured.The failure mechanism of the SMC composites was explored via the Tsai-Wu failure criterion and the matrix stress field theory after interface cracking.The proposed method provides an important basis for studying the failure process of the SMC composites and the corresponding failure behavior.