Study On The Dynamic Response And Failure Mechanism Of Reinforced Concrete Structures Under Strong Shock Wave

Accidents occur frequently in daily production and life.Government office buildings,subway stations,large shopping malls and entertainment places have become the key research objects of anti-explosion design.However,at present,the research in the anti-blast performance of building structures in the anti-blast design code is mainly based on the load types generated by the explosion of chemical explosives and fuel gas explosion,and there is little research on the dynamic response and failure mode of reinforced concrete structure under the strong explosion shock wave.In this paper,the dynamic response and failure mechanism of reinforced concrete columns and reinforced concrete frames subjected to strong blast waves are studied by using the explicit dynamic analysis software LS-DYNA,which is based on the two levels of single member and spatial frame.The main contents of this paper are as follows:(1)The finite element model of typical reinforced concrete column is established,and the optimized grid size is given through the analysis of grid convergence.Through the field explosion test of reinforced concrete beam,the test results of vertical displacement peak value in mid-span and concrete spalling length of beam are compared,and the correctness of modeling method,material parameters,erosion criteria and calculation control parameters is verified.The dynamic response and failure mode of the reinforced concrete column under different working conditions are analyzed,and it is found that the reinforced concrete column mainly exhibits two failure modes of bending failure and bending shear failure under the action of strong explosion shock wave;and the factors that affect the anti-explosion performance of the reinforced concrete column is analyzed.And parameter analysis was carried out to analyze the dynamic response of reinforced concrete columns under the influence of different parameters;(2)Based on the two damage assessment criteria of lateral residual displacement and vertical residual bearing capacity,the damage assessment of reinforced concrete column is carried out,and the relationship between the two damage indexes under the influence of different parameters is analyzed.Based on the residual displacement of column,the damage degree of reinforced concrete column under strong blast wave is evaluated,and the evaluation results are fitted by formula;(3)The dynamic response and failure mechanism of reinforced concrete frame under different explosion directions and intensities are analyzed,and the applicability of alternative path method for collapse analysis of reinforced concrete frame under strong explosion shock wave is analyzed.Then,the factors influencing the antiexplosion performance of reinforced concrete frame are analyzed by parameter analysis,and the interlayer displacement angle pair is introduced.Finally,a multi-scale numerical model is established to verify the accuracy of the numerical model.The dynamic response and failure mechanism of multi-layer frame under strong blast wave are analyzed by establishing multi-scale model of multi-layer frame.