纤维束诱导基体裂纹变形场DGS实验研究

Experimental study of deformation field around the matrix crack induced by fiber bundles using DGS method

本文主要利用数字梯度敏感方法(DGS)和Eshelby等效夹杂理论研究纤维束与基体裂纹的相互作用机制.首先,利用DGS方法得到了碳纳米管改性纤维束模型、未改性纤维束模型基体裂纹尖端的位移场分布及演化规律,并提取了相应的基体裂纹尖端应力强度因子.其次,利用Eshelby等效夹杂理论分析了碳纳米管改性纤维束模型、未改性纤维束模型的基体裂纹尖端应力强度因子的影响机制.最后,比较了碳纳米管改性纤维束夹杂和未改性纤维束夹杂两种模型中基体裂纹尖端应力强度因子的理论预测结果与DGS实验结果,吻合较好.研究成果为纤维束与基体相互作用机制提供了可靠的实验依据及理论参考.

The interaction mechanism between the fiber bundle and the matrix crack using the DGS method and Eshelby equivalent inclusion theory is studied in this paper. First, the displacement field distribution and evolution around the matrix crack tip were obtained experimentally using DGS method and then the corresponding stress intensity factors were extracted from modified fiber bundle/epoxy model and pure fiber bundle/epoxy model. Second, the fracture mechanisms on crack tip stress intensity factor induced by fiber bundles have been analyzed using Eshelby equivalent inclusion theory. Finally, the ratios of Ktip/Ko obtained by DGS experiment show good agreement with the result from the theory prediction. The research result provides a reliable experimental and theoretical basis for understanding the interaction mechanism between the fiber bundle and the matrix crack.