钢箱梁桥面板爆炸冲击响应数值模拟研究

Numerical simulation for response of a steel box girder deck to blast loading

大跨度缆索承重桥梁遭受恐怖爆炸袭击的风险比一般桥梁大。运用LS-DYNA非线性有限元软件,研究了箱包炸弹和小轿车炸弹(TNT当量10～500 kg)桥面爆炸冲击作用下缆索承重桥梁钢箱梁正交异性桥面板的塑性变形、开裂与破口及耗能。结果表明:桥面板的主要耗能机制为盖板和加劲肋的塑性变形耗能,占爆炸输入能量的70%以上;加劲肋和横隔板对桥面板破口有约束作用,TNT当量为300～500 kg时,纵桥向破口尺寸小于等于横隔板间距,并小于横桥向破口尺寸。

Large span cable-supported bridges suffer greater risk of terrorful explosion than normal bridges do. The plastic deformation, rupture, tearing and energy dissipation of an orthotropic steel deck under blasting loads of hand- placed bombs and sedan bombs （TNT equivalent 10kg-500kg） were investigated with nonlinear finite element software LS- DYNA. The results showed that the bridge deckg main energy dissipation mechanisms are the plastic deformation of cover plates and lengthways stiffeners, and the ratio of plastic deformation energy to explosion energy exceeds 70% ; the rupture of deck is constrained by the stiffeners and diaphragms, the lengths of ruptures in lengthways are not longer than the distance between two diaphragms, and shorter than those in width way while TNT equivalent is from 300kg to 500kg.