摘要
动载荷下剪切失稳控制的扩散行为是岩石局部大变形发展和宏观力学性能劣化的诱因。基于广义变分原理建立剪切载荷作用下界面动态失稳的力学模型,得到了关于界面失稳的判别式和扩散方程。基于判别方程得到了剪切力和动力效应对失稳界面角度的影响,结果表明:随着外部剪切作用力的增大,剪切变形带角度有一定程度的增大;随着局部动力系数的增大,即局部惯性作用力的增大,剪切带角度明显减小。结合本征位移求解扩散方程,初步得到其位移解析表达式,位移随加载时间的增加逐渐增大。为了验证理论模型的可靠性,并进一步研究界面失稳的变形行为和对波传播的影响,建立了数值分析模型。分析结果表明:界面失稳为局部剪切破坏滑移的先导条件;界面厚度和剪切力越大,局部位移越大;界面剪切扩散行为极大降低了透射波的幅值,同时也改变了透射波的频率。研究结果可为岩石局部化变形、岩石动态强度等研究提供理论参考。
The diffusion behavior of shear instability control under dynamic load is the inducement for the development of local large deformation and the deterioration of macroscopic mechanical properties of rock.Firstly,the energy function of the unstable interface was established;and then based on the generalized variational principle,the interface disturbance analysis was carried out,while the first and second-order variances of the function were taken into consideration.Thus the governing equation of dynamic instability of the interface under shear load was established.Based on the discriminant equation,the influence of shear force and dynamic effect on the angle of the unstable interface is obtained.The results show that the angle of the shear deformation zone increases to a certain extent with the increase of external shear force.With the increase of the local dynamic coefficient,that is,the increase of the local inertial force,the shear band angle decreases obviously.By solving the diffusion equation with the edge displacement,the analytical expression of displacement was obtained,showing that the displacement increases gradually with the increase of loading time.To verify the reliability of the theoretical model and further study the deformation behavior of interface instability and its influence on wave propagation,the evolution of the fine and microscopic morphology of the contact surface during dynamic shear was described by combining with the SHPB rod-beam experiment technique,and an evaluation method for the influence of the evolution of surface contact parameters on mechanical parameters during interface instability was proposed.The numerical analysis model was established,and its result shows that interface instability is the leading condition of local shear failure slip.With the increase of interface thickness and shear force,the local displacement increases.The interfacial shear diffusion behavior greatly reduces the amplitude and changes the frequency of the transmitted wave.This study provides a good theoretical reference for the study of localization deformation and dynamic strength of rocks.
作者
陈美多
张祥林
袁良柱
赵巨岩
王鹏飞
马昊
徐松林
CHEN Meiduo;ZHANG Xianglin;YUAN Liangzhu;ZHAO Juyan;WANG Pengfei;MA Hao;XU Songlin(CAS Key Laboratory for Mechanical Behavior and Design of Materials,University of Science and Technology of China,Hefei 230027,Anhui,China;Beijing Institute of Space Long March Vehicle,Beijing 100076,China;National Key Laboratory of Science and Technology on Test Physics and Numerical Mathematics,Beijing 100076,China)
出处
《爆炸与冲击》
EI
CAS
CSCD
北大核心
2024年第8期44-59,共16页
Explosion and Shock Waves
基金
国家自然科学基金(11672286,11872361,12372372)
高压物理与地震科技联合实验室开放基金(2019HPPES01)
中石油与中科院重大战略合作项目(2015A-4812)
中央高校基本科研业务费专项资金(WK2480000008)。
关键词
岩石界面
有限变形
剪切局部化
惯性效应
动态失稳
rock interface
finite deformation
shear localization
inertia effect
dynamic instability
