爆炸下考虑钢梁翼缘变形的改进单自由度法

Improved Single Degree of Freedom Method Considering Flange Deformation of Steel Beam Under Blast Loading

为解决爆炸下结构产生较大局部变形时采用等效单自由度方法计算结构整体位移会出现较大误差甚至错误的问题,在单自由度理论基础上,以工字型钢梁为研究对象,通过分析翼缘局部变形对钢梁整体位移的影响规律后,基于提出的钢梁截面简化变形模型对其弯曲抗力函数进行改进,提出钢梁抗爆分析的改进单自由度方法。通过有限元软件ABAQUS数值模拟不同爆炸工况下钢梁的动态位移响应与破坏特征,并与单自由度模型及改进单自由度模型的计算结果进行对比,研究了不同计算模型下钢梁的位移及破坏差异。结果表明:与有限元模拟结果相比,钢梁翼缘局部变形越大,单自由度模型计算结果偏小越严重,而改进单自由度模型计算结果较好,可以更好地适用于钢梁抗爆分析的位移简化计算。

When the structure generates large local deformation under blast loading,the single degree of freedom(SDOF)method will have large errors or even mistakes to calculate the overall displacement of structure.In order to solve this problem,based on the SDOF theory,study on I-shaped steel beam,after analyzing the influence of local deformation of flange on the overall displacement of steel beam,the bending resistance function is improved based on the proposed simplified deformation model of steel beam section.An improved single degree of freedom(ISDOF)method for blast resistance analysis of steel beams is proposed.Finally,the dynamic displacement response and failure characteristics of steel beams under different blast loading are numerically simulated by the finite element software ABAQUS.The results are compared with those of the SDOF model and the ISDOF model,and the displacement and failure differences of steel beams under different calculation models are studied.The results show that compared with the finite element simulation results,the larger the local deformation of the steel beam flange is,the smaller the SDOF model calculation result is.The calculation results of ISDOF model are better,ISDOF model can be better applied to the simplified displacement calculation of blast resistance analysis of steel beams.