CFRP三维铣削仿真模型的建立及层间损伤分析

碳纤维增强树脂基复合材料(CFRP)具有层间结合强度低、各向异性等特点,切削过程中易产生层间损伤。为了对CFRP铣削加工过程中的层间应力、层间损伤进行研究,建立了复合材料三维铣削仿真模型。该模型在结构上采用等效均质建模,层内单元利用VUMAT子程序建立了三维Hashin起始失效准则以及损伤演化过程模型,层间采用Cohesive单元连接以模拟层间损伤的产生及扩展。通过与实验切削力数值的比较,验证了仿真模型的准确性。利用该模型分析了切削力、层间应力及层间损伤随纤维方向角(0°、45°、90°、135°)的变化规律。结果表明:铣削过程加工损伤主要集中在近工件表面。铣削力、层间应力、层间损伤受纤维方向角的影响,纤维方向角为90°与135°时,轴向铣削力较大,层间应力与层间损伤均随纤维方向角的增加而增大,纤维方向角为135°时,层间应力最大,层间损伤最严重。

Establishment of 3D Milling Simulation Model for CFRP and Analysis of Interlaminar Damage

Carbon fiber reinforced polymers(CFRP) have the characteristics of low interlayer bonding strength and anisotropy and interlaminar damage,are easily generated during the cutting process.In order to study the interlaminar stress and interlaminar damage during the milling process of CFRP,a three-dimensional milling simulation model of composite materials was established.Equivalent homogeneous modeling was adopted in the structure.The three-dimensional Hashin initial failure criterion and damage evolution model were established by using VUMAT subroutine for the intralaminar element.The layers were connected by cohesive element to simulate the generation and expansion of interlaminar damage.The accuracy of the simulation model was verified by comparing the simulation and experimental cutting force values.The model was used to analyze the variation of cutting force,interlaminar stress and interlaminar damage with fiber orientation angle (0°,45°,90° and 135°).The results show that the machining damage during milling is mainly concentrated near the surface of the workpiece.Milling force,interlaminar stress and interlaminar damage are effected by fiber orientation angle.When the fiber orientation angle is 90°and 135°,the axial milling force is larger.The interlaminar stress and interlaminar damage increase with the increase of the fiber orientation angle.When the fiber orientation angle is 135°,the interlaminar stress is the largest,and the interlaminar damage is the most serious.