Study On Impact Resistance Of Energy-absorbing Anti-impact Hydraulic Column

Previous researchs have not clearly studied the combined process in energy-absorbing and anti-impact of the hydraulic column-relief valve-energy absorbing component of a energy-absorbing anti-impact hydraulic support for roadway after adding flexible energy-absorbing components.Taking an energy-absorbing anti-impact hydraulic column for research objects,this paper uses LS_DYNA software to analyze the dynamic buckling of the diameter-expanding energy-absorbing component and presents a mechanical model describing energy-absorbing behavior of energy-absorbing components.Based on SIMULINK simulation,the influence of model parameters on the force-displacement characteristics of energy-absorbing components is analyzed.Considering the gravity of the falling rock,the author establishs the general equation of the elastohydrodynamic medium pressure wave propagation in the sealing chamber of the hydraulic column,and studies the liquid impact problem of the conventional hydraulic column.The transfer function method is used to establish the mathematical model of the large flux relief valve,and the influence of damping orifice parameters on the dynamic characteristics of the relief valve is explored.Based on the analysis of influencing factors of liquid impact on conventional hydraulic columns and the simulation results of AMESim,the effects of the characteristics of energy-absorbing components,the location of energy-absorbing components and the characteristics of relief valve on the impact resistance of hydraulic columns are analyzed.By comparing the impact resistance characteristics of energy-absorbing components and relief valves on the hydraulic column,and analyzing the combined process in energy-absorbing and anti-impact of the hydraulic column-relief valve-energy absorbing component,the author studies the co-effect in energy-absorbing and anti-impact between energy-absorbing components and relief valves.The results show that LuGre friction model can reasonably describe the energy absorption behavior of energy-absorbing components.In order to obtain more accurate calculation results,the author suggests that the boundary condition considering gravity of falling rock should be used for theoretical analysis of liquid impact of conventional hydraulic columns.The influence of energy-absorbing component on liquid impact in hydraulic column can be divided into approximate elasticity,flexible giving way to absorpt energy and rigidity three points.On the premise of ensuring that the damping orifice plays the role of eliminating the impact and vibration,increasing the flow-pressure drop coefficient of the damping orifice properly is conducive to the quick opening of the relief valve.The energy-absorbing component limits the energy loading rate acting on the relief valve,prolongs the overflow time of the relief valve,and improves the applicability of the small flux relief valve to different external loads.Aiming at the problem that the maximum dissipated energy of energy-absorbing components is limited,relief valve is used to assist in sharing the dissipated energy of energy-absorbing components.The larger the flux of the relief valve,the more the energy dissipated by the relief valve accounts for the proportion of the total impact energy,thus increasing the rockburst magnitude that the energy absorbing and anti-impact hydraulic column can withstand.The author suggests that the peak bearing capacity and the reaction force in the process of plastic deformation of the energy-absorbing component of the energy absorbing and anti-impact hydraulic column are 1.1~1.5 times the working resistance of the hydraulic column.