装药形状对爆炸作用下钢桥面板损伤的影响研究

Investigation of the Influences of Explosive Shapes on the Damage of Steel Bridge Decks

炸药的装药形状会显著地影响炸药能量的释放方向,因此,不同的装药形状会对爆炸作用下的结构造成不同的响应与损伤。为研究装药形状对爆炸荷载作用下钢桥面板(钢板和U肋加劲钢板)的动力响应和损伤的影响,基于LS-DYNA建立了钢板和U肋加劲钢板在爆炸荷载作用下的有限元模型,并基于现场试验的破坏现象、板的残余位移和加速度时程结果进行了有限元模型的验证。使用基于验证的有限元模型,分析了3种形状(球形、立方体和长径比为1的圆柱体)装药在局部爆炸和整体均匀爆炸作用下钢板和U肋加劲钢板的动力响应和塑性损伤。并在圆柱体装药中考虑圆柱体轴向和径向分别正对钢板和U肋加劲钢板所造成的不同响应与损伤。研究结果表明:在局部爆炸和整体爆炸工况下,圆柱体-1(轴向正对板面)与立方体装药对U肋加劲钢板和平钢板造成的塑性损伤具有较高的相似性;在局部爆炸工况下,圆柱体-1和立方体装药对U肋加劲钢板和平钢板造成的变形的局部特征显著大于圆柱体-2(环形正对板面)和球形装药,平钢板和U肋加劲钢板在局部爆炸工况下会出现明显的内圆顶变形;球形装药爆炸下的平钢板和U肋加劲钢板的位移响应和塑性损伤最小,且球形装药爆炸下钢板和U肋加劲钢板的变形较为均匀;4种装药布置形式的炸药爆炸下,钢板和U肋加劲钢板的位移响应和损伤排序为立方体≈圆柱体-1(轴向正对板面)>圆柱体-2(环向正对板面)>球形。

The charge shape of explosives significantly affects the release direction of explosion energy.Therefore,different explosive shapes lead to different dynamic responses and damage to the structures under blast loads.To study the effect of explosive shapes on the dynamic responses and damages of steel bridge decks(steel plates and U-rib stiffened steel plates)under explosions,finite element models of bare steel plates and U-rib stiffened steel plates under explosion loads were established based on LS-DYNA.The finite element models were verified by experimental results,such as the post-test phenomenon,residual displacement of the plates,and acceleration time histories.Furthermore,the dynamic responses and plastic damage of the steel plates and Urib-stiffened steel plates were analyzed using a verified numerical model.Explosives with three shapes(spherical,cubic,and cylindrical,with an aspect ratio of 1)were considered in this study.The plates were subjected to local and global uniform explosions in this investigation.The different responses and damages caused by the cylinder facing the steel plates and the U-rib stiffened steel plates axially and radially were considered for the cylinder charge.The results show that under the local explosion and general explosion conditions,the plastic damages caused by cylinder-1(directly facing the plate surface in the axial direction)and cubic charge showed significant similarity to the U-rib stiffened steel plate and flat steel plate.In addition,under the local explosion conditions,the local characteristics of the deformation caused by cylinder-l and cubic charge to the U-rib stiffened steel plates and flat steel plates were significantly larger than those of cylinder-2(directly facing the plate surface in the radial direction)and spherical charge.The bare steel plates and U-rib stiffened plates exhibited notable inner dome deformation under the local explosion conditions.The displacement responses and plastic damages of the bare steel plate and U-rib stiffened steel plates under the spherical charge explosions were the smallest,and the deformations of the steel plates and U-rib stiffened steel plates subjected to the spherical charge explosion were relatively uniform compared to other shapes of explosives.Under the explosions of the four types of explosives,the displacement response and damage order of the steel plate and U-rib stiffened steel plate were:cubecylinder-1(directly facing the plate surface in the axial direction)>cylinder-2(directly facing the plate surface in the radial direction)>spherical.