Abstract: In confined explosion, the quasi-static pressure in the enclosed space exists for a long time, and has an important effect on the ultimate deformation of structures so that the dynamic response of structures under confined blast loading is quite different from that under free air blast loading. The dynamic response of square plates under confined blast loading is analyzed. Based on the deformation regularity of thin plates under impact load, a new dimensionless damage number with clear physical meaning is proposed for the deformation prediction of structures under confined blast loading. The influences of the volume of enclosed space, explosive energy, structural dimensions,and strength of material on the deformation response of structure are considered for the dimensionless damage number. The analysis result shows that there is a clear linear relation between the mid-point deflection-thickness ratio and the new dimensionless damage number. An empirical expression with good correlation is presented for deformation prediction of structures under confined blast loading. The influences of membrane force and plate thickness on the structural response are considered in the new dimensionless damage number, which makes it have a wider application with regard to deformation prediction of plates subjected to confined blast loading, especially when the plate experiences large deflection.Key

Key words: confinedblast, quasi-staticpressure, dimensionlessdamagenumber, ultimatedeformation, thinplatestructure