摘要
实际工程中,岩石往往是在冲击荷载作用下发生拉伸破坏,与其在静态荷载作用下展现的力学性质会有明显区别,因此有必要对岩石的动态拉伸力学性能展开研究。首先使用SHPB装置对花岗岩试件进行不同冲击速度下的巴西劈裂试验,研究了高应变率下花岗岩的动态抗拉强度、破坏模式及应力波形曲线。同时基于HJC损伤模型利用LS-DYNA软件对动态劈裂试验进行了数值模拟,并与相近冲击速度下的室内试验结果进行对比,验证了HJC模型对于动态劈裂试验的适用性。结果表明:随着冲击速度的增加,花岗岩动态抗拉强度逐渐增大并与应变率近似为线性相关,破坏裂纹由I型向Y型转变。波形曲线幅值均随应变率增大而增大,其中入、反射波形逐渐趋于矩形,透射波波形由“W”形向“V”形转变。数值模拟下曲线波形及幅值与试验结果近似,在较低和较高冲击速度下,动态抗拉强度差值小于10%。研究结果表明HJC模型对于花岗岩动态劈裂拉伸试验的模拟在较低和较高冲击速度下适用。研究结果可以为今后动态拉伸试验有限元分析的模型选择提供参考。
In practical engineering,rock tensile failures usually occur under impact loads,which is obviously different from its mechanical properties under static loads.Therefore,it is necessary to study the dynamic tensile properties of rock.First,to study the dynamic tensile strength,failure modes and stress waves under high strain rates,the Brazilian disk experiments of granite were performed under different impact velocities by using SHPB system.Meanwhile,LS-DYNA software was used to simulate the dynamic splitting test based on the HJC model,and the results were compared with the laboratory test results at similar impact velocities,which verified the applicability of the HJC model to the dynamic splitting test.The results show that with the increase of impact velocities,the dynamic tensile strength of granite increases gradually and is approximately linearly related to strain rates,and the failure cracks change from I type to Y type.The amplitude of the waveforms increases with the growth of the strain rates,among which the incoming and reflected waveforms tend to be rectangular gradually,and the transmitted waveforms change from"W"type to"V"type.The waveforms and amplitude of numerical simulation are similar to the test results.At lower and higher impact velocities,the difference of dynamic tensile strength is less than 10%,indicating that the HJC model is more suitable for the simulation of the dynamic splitting tensile test of granite in this case.The results can provide a reference for model selections in future finite element analysis of dynamic tensile tests.
作者
赵文博
邓丽梅
赵大凯
王潇
刘殿书
ZHAO Wen-bo;DENG Li-mei;ZHAO Da-kai;WANG Xiao;LIU Dian-shu(School of Mechanics and Civil engineering,China University of Mining and Technology-Beijing,Beijing 100083,China;School of Road and Bridge Engineering,GuangXi Vocational and Technical College of Communication,Nanning 530023,China)
出处
《爆破》
CSCD
北大核心
2022年第3期10-15,共6页
Blasting
基金
国家自然科学基金(U19A2049)。
