长持时爆炸冲击波荷载作用下梁板组合结构的动力响应

Dynamic response of beam-slab composite structures under long-lasting explosion shock wave load

为研究钢筋混凝土梁板组合结构在长持时远爆冲击波荷载作用下的动力响应及毁伤形态,通过实验获得了梁板组合结构的破坏形态和背爆面中心点位移变化。利用有限元软件对钢筋混凝土梁板组合结构的动态响应过程进行数值模拟研究,模拟得到的结构破坏现象与实验吻合较好。在此基础上,分析了梁板组合结构在相同冲量、不同峰值爆炸荷载作用下组合结构的动态响应和破坏过程,并结合挠跨比与破坏形态划分破坏模式。研究结果表明,相同冲量作用下,随着爆炸荷载峰值强度增加,梁板组合构件的破坏程度逐渐增加,破坏模式从弯曲破坏向弯剪联合破坏转换,最后呈现冲切破坏模式;组合构件中板部分发生破坏的时间早于交叉梁部分、破坏程度大于交叉梁。

To identify the anti-explosion performance,dynamic response and typical failure mode of a reinforced concrete beam-slab composite structure,the explosion experiment was conducted by the shock tube,which was used to simulate the long-lasting long-distance explosion shock wave.The failure form of the reinforced concrete beam-slab composite structure,the shock wave variation curve and the displacement change at the center point of the backside surface were obtained through the experiment.The dynamic response process of the reinforced concrete beam-slab composite structure is numerically simulated by finite element software.Compared with the experimental results,it is found that the simulated failure phenomenon is similar to the experimentally observed one,and the peak displacement at the center point of the backside surface is also close to the experimental one.Both of these have verified the accuracy and applicability of the numerical model adopted.On this basis,the dynamic response and failure process of the beam-slab composite structure under the simplified triangular explosion shock wave load are analyzed.The simplified triangular explosion shock wave used in numerical simulation has the same impulse as that in experiment but different peak values and durations.According to the deflection-span ratio a and the failure form,the failure patterns are classified into four modes as light failure,moderate failure,severe failure and complete failure.The results show that the cracks are firstly distributed along the diagonal of the backside surface of the reinforced concrete beam-slab composite structure.Under the same impulse,with the increase of the peak value of the explosion load,the damage degree of the beam-slab composite members gradually deepens.Meanwhile,the failure mode changes from a bending failure to a combined bending-shear failure,and finally appears as a punching failure.The failure of the plate part of composite members occurs earlier than the cross-beam part,while the former’s damage degree is greater than the latter’s.