| In recent years,the explosion accidents have seriously threatened the harmony and stability of the current society.The explosion not only caused casualties,but also caused damage and destruction of building structures or components.The reasonable setting of blast wall can effectively reduce the damage of shock wave to adjacent buildings.At the same time,the structure of blast wall has a great influence on the attenuation of shock wave,but the reason of the influence is not clear.Therefore,it is of great practical significance to study the influence of dynamic characteristics of blast wall structure on the peak overpressure of blast wave.The research work mainly includes the following four aspects:(1)Based on the similarity theory,the equivalent shrinkage model of blast resistant wall is established,the concrete blast resistant wall model is made and the explosion test is carried out.The pressure changes of the measuring points after the explosion are recorded by the pressure sensor and data collector.The pressure time history curve of the blast resistant wall after the explosion is obtained by processing the test data,and the data changes of different measuring points are analyzed.(2)ANSYS/LS-DYNA module is used to establish a three-dimensional finite element model of blast resistant wall.The constitutive relation of material,strain rate effect of material under blast impact and parameter setting of fluid structure coupling are comprehensively considered.The blast field and blast resistant wall are reasonably coupled.Ale technology is used to simulate the model.The calculated results are in good agreement with the experimental data,and the three-dimensional finite element model of the wall can meet the research requirements.(3)Four factors and three levels orthogonal test scheme was constructed,and the peak overpressure of blast wave was taken as the index to study the factors influencing the peak overpressure of blast wave.The results show that the order of influencing factors of overpressure peak value is: explosive charge > height of blast wall > constraint of blast wall >type of site soil.(4)On the basis of the primary and secondary analysis of the influencing factors,the influence of the dynamic characteristics of the blast resistant wall structure on the equivalent force under the direct action of the blast shock wave is further discussed.Based on the existing theoretical knowledge and design specifications,it is proposed that the influence of higherorder frequency on dynamic coefficient should be considered,and the corresponding formula is derived.The standard values of equivalent static load corresponding to different dynamic coefficients in single degree of freedom system and multi degree of freedom system are compared,and the dynamic coefficient of higher-order frequency is closer to the simulation results. |
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