基于位移荷载输入动力时程法的误差分析
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摘要
针对使用位移荷载作输入时存在的一些问题,从时间步长、质量与静动力参与系数、振型截取几个方面对使用位移荷载作多点输入时存在的误差进行分析.通过对比分析发现,位移荷载与加速度荷载存在根本的不同,前者会激发大量的振型,以致用来估计加速度荷载误差的90%质量参与法则不适用于位移荷载;对于位移荷载输入时需要0.001s甚至更小的时间步长,才能获得精确的结果;采用振型叠加法的振型截取可能会引起构件内力的较大误差,需要采用较高的振型数量来减小误差.
The error analyses of multiple-support excitation have been carried out based on time step,mass participated coefficient and displacement load to solve the problem of using displacement load as input.It is found through contrast analysis that displacement load is different from acceleration load,the former could excitate so many models of vibration that the mass participated principle is not applicable to displacement load.To get the accurate result the time step of 0.001s for displacement load is adopted.A large number of models are needed to reduce the errors because the model interception of model superposition method could arouse the errors of internal forces.
The error analyses of multiple-support excitation have been carried out based on time step,mass participated coefficient and displacement load to solve the problem of using displacement load as input.It is found through contrast analysis that displacement load is different from acceleration load,the former could excitate so many models of vibration that the mass participated principle is not applicable to displacement load.To get the accurate result the time step of 0.001s for displacement load is adopted.A large number of models are needed to reduce the errors because the model interception of model superposition method could arouse the errors of internal forces.
引文
[1]潘旦光,楼梦麟,范立础.多点输入下大跨度结构地震反应分析研究现状[J].同济大学学报,2001,29(10):1 213-1 219.
[2]楼梦麟,林皋.地震动空间相关性对水坝地震反应影响[J].水力发电学报,1984,(2):39-46.
[3]王前信,伍国騆.地震多点输入或扰力多点输入时框架的反应[J].地震工程与工程振动,1983,3(2):1-14.
[4]屈铁军,王君杰,王前信.空间变化的地震动功率谱的实用模型[J].地震学报,1996,18(1):55-62.
[5]叶继红,李爱群,刘先明.动力松弛法在索网结构形状确定中的应用[J].土木工程学报,2002,35(6):14-19.
[6]林家浩.随机地震响应功率谱快速算法[J].地震工程和工程振动,1990,10(4):38-46.
[7]Harichandran R S,Vanmarke J.Stochastic variation of earth-quake ground motion in space and time[J].Journal of Engineer-jing Mechanics,1986,112(4):154-174.
[2]楼梦麟,林皋.地震动空间相关性对水坝地震反应影响[J].水力发电学报,1984,(2):39-46.
[3]王前信,伍国騆.地震多点输入或扰力多点输入时框架的反应[J].地震工程与工程振动,1983,3(2):1-14.
[4]屈铁军,王君杰,王前信.空间变化的地震动功率谱的实用模型[J].地震学报,1996,18(1):55-62.
[5]叶继红,李爱群,刘先明.动力松弛法在索网结构形状确定中的应用[J].土木工程学报,2002,35(6):14-19.
[6]林家浩.随机地震响应功率谱快速算法[J].地震工程和工程振动,1990,10(4):38-46.
[7]Harichandran R S,Vanmarke J.Stochastic variation of earth-quake ground motion in space and time[J].Journal of Engineer-jing Mechanics,1986,112(4):154-174.
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