脉冲载荷影响岩石动态断裂韧性的有限元分析

Finite Element Analysis of Influence of Pulse Load on Rock Fracture Toughness

依据岩石材料的力学性质以及中心裂纹圆盘试件在脆性材料断裂韧度测试方面的优越性,提出了在霍布金森压杆上使用中心裂纹圆盘试件来测试岩石动态断裂韧度的试验方法。利用有限元分析软件,通过对该试验系统的纯Ⅰ型加载情况下的三维动力学有限元计算,系统的分析了加载脉冲上升沿对岩石类材料动态断裂韧度测试的影响。通过比较中心裂纹圆盘试件动态应力强度因子的近场解和远场解,依据有限元分析结果确定动载荷脉冲上升沿时间对岩石动态应力强度因子的影响,从而选择合理的时间值。

A new method for testing rock dynamic fracture toughness was proposea according to mechanics property of rock and the advantages of central cracked circular disk specimen in testing dynamic fracture toughness of brittle materials. In the method rock dynamic fracture toughness is by using central cracked circular disk specimen in split hopkinson pressure bar. Influence of pulse rising time on dynamic fracture toughness of brittle materials was analysed by three dimension dynamic finite element computation under conditions of pure mode I dynamic loading on the experimental system. By comparing the near and far field solution of the stress intensity factors of the central cracked circular disk specimen, the influence of pulse rising time on rock dynamic stress intensity factors was determined according to finite element analysis results. So that, the appropriate pulse rising time for the test can be selected.