【作者】 许泽建； 李玉龙；

【Author】 XuZejian Li Yulong (School of Aeronautics,Northwestern Polytechnical University,Xi’an China)

【机构】 西北工业大学 航空学院；

【摘要】 采用实验-数值方法对30CrMnSiA钢的三点弯曲试样在6种子弹速度的冲击载荷作用下进行了动态断裂韧性的测试,并对其加载速率相关性进行研究。实验由Hopkinson压杆系统完成,试样的起裂时间采用应变片法测得。结合有限元三维动态模拟,得到了不同加载速率下试样动态应力强度因子的时间历程,并由实测的起裂时间确定材料动态断裂韧性。结果表明,30CrMnSiA钢在本工作加载速率范围内(1.17-1.82×10⁶MPa·m^1/2/s)以准解理断裂的形式发生破坏,其动态断裂韧性随加载速率的增加而减小。结合断口形貌对上述研究结果进行了微观机理分析。更多还原

【Abstract】 c fracture toughnesses KId for 30CrMnSiA steel,subjected to impact loads with six striker velocities was measured using an experimental-numerical method.The dependency of K_1don loading rate for this material was also investigated.The tests were performed on three point bending specimens with Hopkinson pressure bar and the fracture initiation time was determined by strain gauge.With 3-D transient finite element analysis,the dynamic stress intensity factor histories under different loading rates were obtained and the values of dynamic fracture toughness were determined by fracture initiation time.The results show that within the loading rate range(1.17-1.82×10⁶ MPa·m^1/2/s),30CrMnSiA steel specimens failed by quasi-cleavage fracture,and the K_1dvalue decreased with an increasing loading rate. Mechanisms of the results were discussed microcosmically according to fractography.更多还原