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压力-冲量(P-I)曲线是结构构件在爆炸荷载作用下的初始设计及在爆炸荷载作用后的破坏评定的有效工具。目前,确定结构构件的P-I曲线采用的方法均是基于单自由度结构体系假定的,并且多以结构构件的中点位移作为破坏指标。然而在爆炸荷载作用下,结构构件大多因高阶响应而发生局部破坏,且可能发生弯剪破坏。因此,通过将结构构件简化为单自由度体系模型并且选择结构构件中点位移为单一破坏指标获得的结构构件的P-I曲线,不能准确评定其破坏程度。利用LS-DYNA有限元动力分析软件,建立了典型钢筋混凝土板在爆炸荷载作用下响应和破坏的分析方法,提出了基于钢筋混凝土板跨中截面受弯剩余承载力的破坏指标以及利用数值方法确定钢筋混凝土板跨中截面受弯剩余承载力的步骤。同时,综合分析数值模拟结果,拟合了钢筋混凝土板P-I曲线的数学表达式,提出了一种简化了的确定钢筋混凝土板P-I曲线的方法,采用该方法确定的P-I曲线可用来对任意爆炸荷载作用后钢筋混凝土板的破坏进行评定。
The pressure-impulse (P-I) curve is an effective tool for the initial design of structural members under blast loads and the assessment of damage after blast loads. At present, the methods used to determine the P-I curves of structural members are all based on the one-degree-of-freedom structural system, and the displacement of the mid-point of structural members is mostly used as the damage index. However, under the explosive load, most of the structural members are partially damaged due to the high-order response, and the bending failure may occur. Therefore, the P-I curve of the structural member obtained by simplifying the structural member to a single-degree-of-freedom system model and selecting the point displacement in the structural member as a single failure index can not accurately assess the degree of damage. Based on LS-DYNA finite element dynamic analysis software, the analysis method of typical reinforced concrete slab under explosive load is established, and the failure index based on the residual flexural capacity of the mid-section of the slab is presented and the numerical method is used to determine Reinforced concrete slab midspan flexural residual capacity of the step. At the same time, by comprehensively analyzing the numerical simulation results, the mathematical expression of the PI curve of the reinforced concrete slab is fitted and a simplified method of determining the PI curve of the reinforced concrete slab is proposed. The PI curve determined by this method can be used to simulate any explosive load After the effect of the destruction of reinforced concrete panels were assessed.