| The current international situation is complex and changeable.Explosion attacks and accidental explosions in various parts of the world are still vividly remembered.If the prestressed reinforced concrete T-beams are damaged as a result,it will cause significant damage to people’s property security and economic and social stability.Due to the high cost of the anti-explosion test related to prestressed T-beams,the observation of specimen damage is discontinuous,and there are hidden safety hazards,so the method of numerical simulation has been paid special attention.In this paper,based on ANSYS/LS-DYNA software,a numerical simulation study on the prestressed reinforced concrete T-beam under the composite action of shock wave and fragment group is carried out.The main research contents and results are as follows:(1)The finite element model in this paper is composed of ammonium oil(ANFO)explosives,fragment groups,air,prestressed reinforced concrete T-beams and end supports.The numerical simulation of the prestressed reinforced concrete slab test,the prestressed concrete beam drop weight impact test and the fragment group erosion test on the concrete slab under shock wave has verified the effectiveness of the fluid-structure coupling algorithm and the material constitutive model The reliability of the treatment method of curved prestressed tendons with multi-section broken lines was used to verify the rationality of the numerical simulation parameters of fragment flying speed and penetration depth.(2)The effects of shock wave alone,fragment group alone and their combined effect on the damage effect of T-beam are analyzed and compared.The research shows that the composite effect of shock wave-fragment group on T-beams is greater than that of a single load,but less than the linear superposition of the effects of two loads alone.(3)The influence of the T-beam’s own parameters on its anti-explosion performance was explored.The research shows that with the increase of tension control stress,longitudinal reinforcement ratio and stirrup reinforcement ratio in non-densified area,the anti-explosion performance of T-beams is nonlinearly enhanced;The enhancement effect is not obvious.(4)The effect of load parameters on the anti-explosion performance of T-beams is studied.Studies have shown that: explosives are located at the top of the beam:when the proportional distance is the same,the quality of the explosives plays a leading role in the damage of the beam;when the explosion center moves along the width of the beam,the smaller the distance of the explosion center from the center point,the greater the dynamic response of the displacement of the bottom of the beam;the explosion center is along the beam When moving in the long direction,the position of the peak displacement at each point of the longitudinal bridge at the bottom of the beam coincides with the position of the burst center.Explosives are located on the side of the beam: the web has severe local damage,and the concrete has a large area of peeling through.The explosive is located at the bottom of the beam:the greater the distance from the center of the explosion center,the more severe the damage to the flange and web.(5)A T-beam protection and reinforcement study was conducted.Studies have shown that CFRP plates ensure a certain ductility of the members,resulting in less mass loss of the beam,but limited dynamic response reduction of displacement;the ability of steel plates to reduce the mass loss of components is slightly weaker than CFRP plates,but the effect of reducing the dynamic response of displacement is stronger than CFRP Plate;the reinforcement method with the CFRP plate first and the steel plate added afterwards has the best comprehensive protection effect... |
