爆炸冲击作用下不同材料箱型梁桥损伤分析

Damage Analysis of Box Girder Bridge with Different Materials under Explosion Impact

利用ANSYS/LS-DYNA有限元软件,采用三阶段耦合方法模拟了爆炸作用下某实际钢筋混凝土小箱梁桥局部毁伤与整体毁伤过程,得到了在35kg当量炸药下箱型梁桥关键构件的破坏模式与损伤机理,研究了爆炸作用下不同目标材料对箱型梁桥的损伤影响。基于靶板最大位移公式,得到了爆炸冲击作用下不同箱型梁桥材料强度与损伤Y向位移比值之间的联系。结果显示:当炸药当量为35 kg时,箱形梁桥整体未出现倒塌,顶板毁伤最为严重,出现贯穿损伤,混凝土剥落严重,出现椭圆形炸坑;腹板与顶板交界处出现裂缝,模拟过程印证了冲击波爆炸时先在表面形成环状向外扩散,随后水平扩散至翼缘板边缘再开始向下蔓延的理论;随着材料强度不断提高,箱型梁桥损伤面积不断减小,箱梁稳定性也逐渐提高。

With ANSYS/LS-DYNA finite element software,the local damage and overall damage process of an actual reinforced concrete small box girder under explosion was simulated by the three-stage coupling method.Thereby,the failure mode and damage mechanism of the key components of the box girder bridge under 35 kg equivalent explosive were obtained.Then,the influence of the material of the box girder bridge on the explosion damage effects was studied.Results showed that when the explosive equivalent is 35 kg,the box girder bridge does not col-lapse as a whole,but the roof is extremely damaged with penetration damage,severe concrete spalling oval crater.Simultaneously,cracks appear at the junction of the web and the roof.The simulation process verified that the explosion shock is firstly formed on the surface and diffuses outward in ring-shape,and then horizontally diffuses to the edge of the flange plate and begins to spread downward.With the increase of the material strength,the damage area of the box girder bridge decreases,and the stability of the box girder gradually increases.