钢框架在冲击波和破片复合作用下的破坏倒塌机理

Collapse mechanism of steel frame under combined actions of shock wave and fragments

为了探究钢框架在近爆冲击波和预制破片群复合作用下的抗爆抗倒塌性能,利用有限元软件ANSYS/LS-DYNA进行模拟爆炸分析。首先,对钢框架的梁柱节点进行分离式建模;然后,在炸药表面张贴预制破片,实现冲击波和破片的复合,得出冲击波、破片单独作用以及二者复合作用时对钢框架的不同破坏规律;最后,运用变参分析研究冲击波和破片复合作用下,钢柱的不同迎爆面、钢材强度以及节点排布形式等因素对结构的影响。研究结果表明:冲击波与破片复合作用下钢框架的破坏程度更严重;炸药正对翼缘面起爆时,对结构的破坏程度远远小于正对腹板面的破坏程度,应重点防护正对钢柱腹板面的起爆;钢材强度的选择适当即可,钢材强度过高并不能显著提高抗爆性能;炸药离地面高度越低,距螺栓节点域越远,节点域的破坏程度越低,结构越不容易倒塌;当比例距离保持不变时,随着炸药量增大,结构的破坏程度提高;高强度摩擦型螺栓的数量以及排布方式也会影响框架的抗爆抗倒塌性能,螺栓数量越多越安全,并应根据螺栓数量合理选择排布方式。

In order to explore the anti-explosion and anti-collapse performance of steel frame under the combined actions of near-explosion shock wave and prefabricated fragments group,the finite element software ANSYS/LS DYNA was used to simulate the explosion analysis.Firstly,the beam-column joints of steel frame were modeled separately.Secondly,the composite action of shock wave and fragment was realized by posting prefabricated fragments on the surface of explosive and the different influence of steel frames under the separate action of shock wave and fragment and the composite action of them were obtained.Finally,the variable parameter analysis was used to study the influence of different blast-facing surfaces,steel strength and node arrangement forms of steel columns on the structure under the combined action of shock wave and fragments.The results show that the damage degree of steel frame under the combined action of shock wave and fragment is more serious.When the explosive is detonated on the flange surface,the damage to the structure is far less than that of the web surface and the key protection is to detonate on the web surface of the steel column.The selection of steel strength is appropriate and too high strength can not significantly improve the blast resistance.The lower the height of the explosive from the ground,the farther away from the bolt joint area,the lower the damage degree of the joint area and the more difficult the structure to collapse.When the proportional distance remains unchanged,the damage degree of structure increases with the increase of explosive quantity.The number and arrangement of high-strength friction bolts will also affect the anti-explosion and anti-collapse performance of the frame.The more the number is,the safer the frame is.The arrangement should be reasonably selected according to the number.