Finite Element Simulation Of Single Tooth Impact Sandstone Test

Hard rock geology is a common geological condition in the construction of tunnel and underground engineering.Rock materials are greatly affected by the surrounding environment during the formation process,and their physical properties are very complex.Therefore,the study of rock dynamic mechanical parameters and rock breaking efficiency is of great significance for engineering construction.In this dissertation,two kinds of sandstone materials(red sandstone and gray sandstone)with different compressive strength are taken as the research object.The separated Hobkinson pressure bar experiment is combined with numerical simulation to study the dynamic mechanical properties of rocks.The main contents of this paper are:(1)First,ANSYS/LS-DYNA was used to model the dynamic behaviour.Then,the Holmquist-Johnson-Cook(HJC)constitutive model was used to carry out a large number of numerical simulations on the impact compression experiment of sandstone samples.By constantly changing the values of some parameters in the model,a comprehensive analysis of the meshing method,the parameter sensitivity of the HJC model and the failure types in the numerical simulation calculation is carried out.(2)A complete set of material parameters of the HJC constitutive model were obtained by fitting the impact compression test results of sandstone with the HJC constitutive model.And the method to determine the parameters of HJC model is summarized.Waveform comparison and error analysis were used to verify the accuracy of numerical simulation.(3)The HJC model parameters obtained above were used to carry out finite element simulation of the toothed impact sandstone experiment under impact load,and then compared with the experimental data to verify the validity of the HJC parameters once again.At the same time,by changing the tooth shape and coronal height,the experiment of impact sandstone with different tooth shape under impact load was expanded.A set of rules between tooth profile and rock breaking efficiency are summarized.And some feasible suggestions are put forward to improve rock breaking efficiency and speed up the project progress.