Numerical Simulation Study on Dynamic Impact Mechanical Properties of Coal Rock Mass Based on LS-DYNA
At present,research on the dynamic mechanical properties of coal and rock has gradually become a hot research topic,but most of the dynamic load experiments are completed instantaneously,and some damage details cannot be studied in depth.Therefore,this study is based on the rock Holmquist-Johnson-Cook model and uses LS-DYNA software to conduct numerical simulation research on the Hopkinson compression bar experiment of coal rock samples under low-speed impact loading.At the same time,the whole experimental process is reproduced with the help of LS-PrePost postprocessor,so as to reproduce the damage process and failure details of coal rock impact failure.The results show that:(1)the stress-strain curve of coal rock impact load experiment based on HJC constitutive simulation is consistent with the measured stress-strain curve,in which the peak value of simulated stress is 7.03 MPa,and the relative error is 18.1%.(2)Under the impact loading of 3.693 m/s,both ends of coal rock are destroyed to form small fragments,and then tensile failure occurs along the axial direction of coal rock,forming axial cracks and penetrating through the coal rock specimen.Finally radial cracks are generated.Under the condition of low velocity impact,coal rock failure forms fragments of different sizes without obvious regularity,in which large and small pieces account for about half.(3)In this study,the energy consumption of coal rock under impact load is divided into three main stages.The energy consumption rate of coal rock increases slowly at first,then increases sharply,and finally tends to be flat.
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