Failure mechanism of anti-outburst ventilation door under impact of coal-rock gas dynamic disasters shock waves

Anti-outburst ventilation doors are the key structures to maintain the stability of the ventilation system. After a coal-rock gas dynamic disaster, the anti-outburst ventilation doors are subjected to significant impact forces and are prone to failure. If the ventilation doors fail, gas backflow, which can severely trigger secondary disasters. To study the failure mechanism of anti-outburst ventilation doors caused by the shock waves of coal-rock gas dynamic disasters, a P-I theoretical model for the buckling failure of ventilation doors is established with the overpressure-impulse theory of shock waves as the core. The LS-DYNA finite element software is used to simulate the dynamic response of ventilation doors under the impact of shock waves. And compare the damage situation of the ventilation door obtained from the simulation with that obtained from the P-I theoretical model. The results show that: the root cause for the failure of ventilation doors caused by the shock wave is that the overpressure and impulse generated by the impact load alter the response mode of the ventilation doors; the weak areas of ventilation door are in the central area of the door panel and at the connections between the door panel and the door frame; when the initial gas pressure is more than 1 MPa, the 10 mm thick Q235 steel anti-outburst ventilation door experiences buckling failure; the distribution of equivalent stress, displacement, velocity, and energy fields for ventilation doors shows similarities in different thickness; as the thickness of the ventilation door increases, the equivalent stress, displacement, velocity, and energy under the same impact load decrease, resulting in improved resistance to disasters. And higher-strength steel materials exhibit better impact resistance. The determination of ventilation door failure in the numerical simulation is consistent with the results obtained from the P-I theoretical model. The P-I theoretical model can be used to determine whether ventilation doors experience buckling failure. Using the yield limit of the material as the criterion, a limit state equation for the buckling failure of ventilation doors is established. When the limit state equation is greater than 0, the ventilation doors undergo buckling failure. The results provide theoretical guidance for installing anti-outburst ventilation doors and preventing coal-rock gas dynamic disasters.