【作者】 杨琼；

【导师】 赖明； 李英民；

【作者基本信息】 重庆大学 ， 防灾减灾工程及防护工程， 2003， 硕士

【摘要】 人造地震动因其任意性和统计性等特点而成为时程分析用输入地震波的一个与实际记录同等重要的来源。目前常用的反应谱拟合技术能对给定单一阻尼比反应谱进行较好的拟合，但在目标谱以外其它阻尼比反应谱的拟合上有较大误差，这就是反应谱拟合技术中存在的多阻尼比反应谱拟合问题。事实上，具有不同阻尼比的结构就应有不同设计反应谱与之对应，《建筑抗震设计规范》（GB50011-2001）[6]已规定了不同阻尼比的标准设计反应谱。与此相适应，时程分析用的人造地震动应能同时拟合不同阻尼比的多条反应谱。本文通过分析多目标优化问题的解的意义和常用解法，在比较现有的几种常用优化算法的基础上，选用遗传算法这种自适应全局优化概率搜寻算法作为本文的搜寻方法，将其与多目标优化理论有机地结合在一起，形成多目标遗传算法，并将其引入地震动仿真，形成基于遗传算法拟合多阻尼比反应谱的地震动仿真程序。最后设计算例比较了本文方法与传统三角级数法在拟合标准反应谱和实际记录重现两方面的优劣，并对本文方法拟合实际记录反应谱产生的地震波进行了相似性检验。得出的结论主要有：① 本文基于遗传算法拟合多阻尼比反应谱的地震动仿真程序，其所造出的人造波能兼顾其在不同的阻尼比反应谱上的拟合精度。较好地解决多阻尼比反应谱拟合问题；② 本文方法通过一次运行就能获得一组具有集系特性的地震动，在拟合多阻尼比反应谱的人造地震波集系的仿真方面有传统方法所不能比拟的优势，产生的人造波或人造波集系可满足工程抗震设计需要；③ 在遗传算法中，交叉概率和变异概率是影响收敛速度的重要参数，本文采用的改进自适应交叉概率和变异概率，可以根据当前样本的好坏程度来自动地选择适当的交叉概率和变异概率，以保证算法始终以较好的速度向Pareto最优解集逼近。本文最后分析了目前研究的不足，并对后续工作进行了展望。更多还原

【Abstract】 Artificial ground motions, for their optional and statistic properties, are regarded as an important form of input for structural time history analysis in contrast to the actual records. Present simulation methods which are mostly derived from spectra-compatible technique do well suit for single-damping-ratio-spectra simulation, but the simulation precision is not satisfactory when the spectrum isn’t the object spectrum. In fact, there should be different design spectra corresponding with the structures of different damping-ratios, the new Code for Seismic Design for Buildings (GB50011-2001) has provided corresponding spectra for structures with different damping-ratios. Obviously, the artificial ground motions used for structural time history analysis should well coincide with multi-damping-ratio-spectra.Based on the comparison of the conventional algorithms for multi-objective optimization and genetic algorithms, a method for the simulation of multi-damping-ratio-spectra is proposed in the thesis which combines the multi-objective optimization algorithms and genetic algorithms. The program corresponding to the method is also developed and the method is proved to be feasible and convenient by an example at the end of the thesis.The main conclusions drawn from the research of the thesis are as follows.① The method proposed in this thesis do well in solving the problems of multi-damping-ratio-spectra simulation.② It is convenient to obtain the Pareto optimal solution set of the multi-object question by using implicit parallel genetic algorithms and the method can meet the practical needs for simulating ground motions coinciding with multi-damping-ratio-spectra in seismic design.③ The crossing rate and variance rate are important parameters of genetic algorithms which affect the rate of convergence, the adapting rate of cross and variation in this paper can auto-adapt and according to stand or fall of current sample, it assures the sample approach to the Pareto optimal solution set in fast convergent speed.At the end of this paper, the disadvantages of present study and the recommendations for future research are set forth.更多还原