结构训练营回顾|反应谱分析
反应谱分析是瞬态响应分析的一种近似,大致地确定结构在瞬态荷载作用下的最大响应。在建筑领域,用于预测地震中建筑物各部分的最大响应。在航空领域,用于预测飞机受冲击荷载时飞机内每台设备的最大响应。它是抗震设计中最常用的分析方法。
反应谱分析先将整体结构的多自由度动力平衡方程转换为多个单自由度平衡方程,然后利用反应谱函数求出每一个单自由度的平衡方程的最大响应值。通常情况下,对特定地区或国家中发生的历史地震波数据进行统计而形成反应谱,称为设计谱,然后利用设计谱进行结构的抗震分析。对于每一个单自由度系统,当激励频率等于单自由度系统的固有频率时,获得最大响应。整个结构的响应是单自由度系统响应的组合,组合方式有:SRSS(Square Root Of The Sum Of The Squares), ABS(Summation Of The Absolute Value), NRL( U.S.Naval Response Lab Shock Design Modal Summation), CQC(Complete Quadratic Combination Method), TENP(Ten Percent Method) 。反应谱分析应用广泛,但仍然是瞬态响应分析的近似方法,在抗震设计中很常用。与传统的瞬态响应分析相比,计算比较简单,效率比较高。另一方面,反应谱分析使用设计谱数据而不是直接输入地震波,输入的荷载不直观,只能获得最大结果。不能获得结构随时间变化的响应,结果的精确度没有瞬态响应高。
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附:相关文献材料
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首次发布时间:2022-11-25
最近编辑:2年前