Hopkinson压杆测试材料动态断裂韧性的数值模拟

Numerical Simulation of Dynamic Fracture Toughness Test Using Three-Point Bending Specimen in SHPB

用ABAQUS有限元软件并结合3D断裂力学软件ZENCRACK,建立了三维有限元模型,对霍普金森压杆测试材料的动态断裂韧性进行了数值模拟,同时建立了二维平面应变有限元模型。有限元模型包括整个实验装置(子弹、入射杆、试样和支座),并对3种不同初始裂纹长度的三点弯曲试样在同一速度子弹打击下进行了计算。起裂时间通过RKR局部应力断裂准则获得,结合计算得到的动态应力强度因子冲击响应曲线,最终得到材料的动态断裂韧性。以实验结果为基准,对比三维和二维有限元计算结果,发现三维有限元的计算结果优于二维计算结果。

This paper examines 3D and 2D numerical simulations of dynamic fracture toughness test using TPB specimen in SHPB by using commercial code ABAQUS 6.8 and 3D fracture mechanics code ZENCRACK 7.7. The finite element model includes the whole experimental device （the projectile,the input bar, the specimen and the supporting device）. Three cases of specimens with different initial crack length impacted by projectiles were simulated, and dynamic stress intensity factor impulse response curves were obtained. The dynamic initial fracture times, tf, were extracted from RKR local stress fracture criterion. The material dynamic fracture toughness are successfully obtained from numerical simulations. The simulated results from 2D and 3D FEM are compared with benchmark tests,finding that 3D finite element results are better than 2D results.