利用MTS试验机和分离式Hopkinson拉杆对2种碳纤维/环氧树脂(T300/epoxy)层合板试件[(45/-45)4]s和[(0/45/90/-45)2]s进行了准静态(应变率10^-5-10^-4s^-1)、中速(应变率10^-1-10^1s^-1)和高速(应变率10^2-10^4s^-1)冲击拉伸试验。在热力学框架内建立了基于损伤能释放率的弹塑性动力损伤本构模型,用该损伤模型来分析试件的动态拉伸失效过程。模型中提出了3种基本损伤机制(纤维断裂、基体开裂及面内剪切)的演化规律,通过对损伤阈值黏性归一化的方法考虑了应变率对损伤演化的影响。编写了该模型有限元用户材料子程序,并模拟了拉伸试验过程,计算结果表明该模型能够较好地模拟碳纤维/环氧树脂层合板动态拉伸失效过程。
Tensile tests were carried out on two kinds of carbon fiber/epoxy laminates specimen([(45/-45)4]s and [(0/45/90/-45)2]s) at quasi-static(strain rate 10^-5~10^-4 s^-1),intermediate(strain rate 10-^1~10^1 s^-1) and high strain rate(strain rate 10^2~10^4 s^-1) using the MTS material machine and tensile split Hopkinson bar.A damage constitutive model based on the damage energy release rate was derived within a thermodynamic framework to analyze the dynamic failure of carbon fiber/epoxy.Three damage evolution laws associated with three damage mechanisms(fiber breakage,matrix cracking and shear in plane) were proposed.A procedure resembling the regularization used in viscoplasticity was adopted to take the strain rate into account on damage evolution.The model was coded and implemented into finite element software.The tests were simulated using the model,and the results verify that the model can simulate the dynamic tensile failure well for carbon fiber/epoxy laminates.