爆炸条件下结构超压-冲量曲线简化计算研究

Simplified calculation method for pressure-impulse curve of a structure under blast load

超压-冲量(P-I)曲线可用于快速评估爆炸荷载作用下建筑结构的毁伤效应。基于单自由度等效体系运动方程和结构变形的理想弹塑性模型,在传统能量法基础上考虑阻尼影响,运用图像法计算阻尼耗能,得到了P-I曲线冲量区和准静态区的渐进线方程,在此基础上通过大量计算,得到了P-I曲线动态区的拟合公式。提出的简化计算公式与运用Newmarkβ法计算结构响应得到的P-I曲线相比较为一致,验证了所提方法的合理性。通过算例表明,随着延性比的增大,P-I图的冲量渐近线和准静态渐近线的值逐渐变小;随着阻尼比的增大,P-I图的冲量渐近线和准静态渐近线的值逐渐变大,且阻尼比对冲量渐近线影响明显。

Pressure-impulse（ P-I） curves can be used to quickly assess damage effect of a structure under blast load. Based on motion equations of an equivalent single-DOF system and structural deformation＇s ideal elaso-plastic model,damping effect was considered with the traditional energy method,and damping energy dissipation was calculated by using the image method. The asymptote equations of quasi-static region and impulse region of a P-I curve were obtained,and the fitting formulas for dynamic region of a P-I curve were obtained through a large amount of calculation.The calculation results with the proposed simplified calculation formulas agreed well with P-I curves obtained using structural analysis of Newark method. The rationality of the proposed method was verified. The calculation results showed that the values of impulse asymptote and quasi-static asymptote decrease with increase in ductility ratio; the values of impulse asymptote and quasi-static asymptote increase with increase in damping ratio,and the damping ratio has an obvious effect on impulse asymptote.