动载作用下岩石类材料破坏模式及能量特性

Damage modes and energy characteristics of rock-like materials under dynamic load

对岩石类材料的破坏模式和能量特性进行分析研究,利用ANSYS/LS_DYNA数值模拟软件模拟SHPB冲击的整个过程。通过对试验和数值模拟所得测试曲线进行对比确定模型的有效性,进而分析试件中有效应力的传播过程,提出试件张应变破坏、轴向劈裂拉伸破坏、压碎破坏的3种破坏模式;通过对数值模拟所得试件的内能-时间历程分析表明,试件的内能具有显著的应变率效应,在应变率较低时,可以划分为2个阶段,而在应变率较高时,可以划分为4个阶段。

An in-depth research is carried out on damage modes and energy characteristics of rock-like materials, with the whole impact process of spit Hopkinson pressure bar（SHPB） being simulated by ANSYS/LS-DYNA. A comparison between the experimental stress-strain curve and the curve derived from numeral simulation is made, the model＇s efficacy is proved; and the transmitting process of effective stress within the specimen is duly analyzed, three modes of damage are identified： tearing strain damage, axial splitting tensile damage and crushing damage. By analysing the history curve of specimen internal energy obtained via numerical simulation, it is found that the internal energy has an evident strain rate effect： at lower strain rate, the time history of the internal energy can be divided into two stages, and at high strain rate it can be categorize into four stages.