爆炸荷载下背爆面柔性聚脲防护混凝土靶板的反直观行为OA北大核心CSTPCD

The final deformation of a metal structure under impulsive load occurring in the direction opposite to that of loading,which is a phenomenon known as counter-intuitive behavior.It was found that the flexible polyurea-protected concrete target plate on the back blast surface also experienced counter-intuitive behavior under 75 g TNT blast load.To investigate the counter-intuitive behavior of the flexible polyurea-protected concrete target plate on the back blast surface under blast load,a fi-nite element model of the back blast surface of the flexible polyurea-protected concrete target plate subjected to blast load was developed using the ANSYS/LS-DYNA finite element software.The finite element model was utilized to analyze the dynamic re-sponse regularity of the flexible polyurea sheltered concrete target plate on the back blast surface,and to study the occurrence mechanism of the target plate's counter-intuitive behavior from the perspective of energy.Taking the center point displacement and deflection of the concrete target plate as indexes,the influence of the amount of explosive charge and coating thickness of polyurea on the counter-intuitive behavior of the target plate was analyzed parametrically.The results demonstrate that the counter-intuitive behavior of target plate is attributed to strain energy release from the polyurea coating,energy dissipation from concrete damage,and mutual transformation of energy between both materials.Furthermore,it is found that explosive charge mass is the dominant factor affecting counter-intuitive behavior.The concrete target plate is unable to undergo counter-intuitive behavior when either the charge mass was too small or too large.Within a range of coating thicknesses from 2 mm to 8 mm,an initial increase followed by subsequent decline in bending degree was observed for the target plate exhibiting counter-intuitive behavior.