基于零厚度内聚力单元单向碳纤维增强树脂基复合材料微观切削机理研究

Microscopic Cutting Mechanism of Unidirectional Carbon Fiber Reinforced Plastics Based on Zero Thickness Cohesive Element

为探究碳纤维复合材料(CFRP)微观切削机理,通过有限元法,采用零厚度内聚力单元模拟界面相,碳纤维建模呈圆柱状并随机分布于基体中,以此来真实反应CFRP的微观结构。通过对各组成相设置不同的材料本构、材料失效和演化准则,对4种典型角度(0°、45°、90°、135°)进行直角切削仿真,探究不同纤维角度下单向碳纤维增强树脂基复合材料(UD-CFRP)在切削过程中的微观切削机理。结果表明:不同纤维角度下CFRP的微观破坏形式不同,切削0°CFRP时破坏主要以界面开裂和纤维折断为主,切削45°和90°CFRP时主要是刀具的侵入破坏,切削135°CFRP时则发生纤维的断裂和沿纤维方向的裂纹,纤维断裂点在刀刃下方。最后,通过实验验证了微观模型的准确性。

In order to explore the microscopic cutting mechanism of carbon fiber reinforcement plastics(CFRP),the zero thickness cohesive element was used to simulate the interface phase by finite element method.The carbon fibers were cylindrical and randomly distributed in the matrix to reflect the microstructure of CFRP.Different constitutive rules,material failure and evolution criteria were set up for each constituent phase.Four typical orientation(0°,45°,90°and 135°)were simulated to investigate the microscopic cutting mechanism of unidirectional carbon fiber reinforced plastics(UD-CFRP)under different fiber orientation.The results show that the microcosmic damage of CFRP is different at different fiber orientation.Interfacial cracking and fiber breakage are the main failure modes in cutting 0°CFRP,tool invasion is the main failure mode in cutting 45°and 90°CFRP,fiber breakage and cracks along fiber direction occur in cutting 135°CFRP,fiber breakage point is below the edge of the tool.Finally,the accuracy of the microscopic model is verified by experiments.