The Propagation Law Analysis And Study Of Stress Wave On Impact Cutting Of Coal

This thesis firstly analyzes the fragmenting mechanism and the faults of the common used drum shearer in the coal mining. We make out the theory of compact cutting of coal combining the characteristic of coal. According to the theory, we design and manufacture the impact mining machine. The underground industrial experiment of the model machine had gotten the expected result. Both the theory analysis and experiment provide that the impact-mining machine can solve the mining problems.In order to perfect this theory and instruct the improvement and application of the machine, the author emphatically studies the propagation of stress wave in coal and detailed analyzes both the three stages that the stress wave propagates in the coal and the propagation law of the stress wave and the stress state of the inner material points of each stage. From this study, we gain therelationship of the stress value and the compact stress at random points, also obtain the reason and the time of the possible maximum stress. This thesis also points out that if we choose the right stress wave form it will produces the higher stress concentration. In addition, this thesis researches the dissipation of energy in process of compact mining, the split thickness of impact and the relationship between the useful energy and the impulsive force. Finally, we make the numerical stimulation of the process of the impact mining by finite element method and ANSYS/LS-DYNA through which we draw a reasonable conclusion, verify the truth of this theory and the feasibility of this machine.