子结构拟动力试验的模型修正法

分别针对剪切模型和杆系防屈曲支撑模型,采用有限元软件OpenSEES整体时程分析方法,研究了试验子结构数量对子结构拟动力试验结果的影响。结果表明:随着试验子结构数量的增多,试验结果精度逐渐提高,呈现出近似二次抛物线形变化规律。在构件数量较多结构体系中,试验子结构数量较少时,子结构拟动力试验的精度不高,试验的意义不大。针对一个单跨两层带斜撑框架模型,基于OpenSEES进行虚拟子结构拟动力试验,采用最小二乘法,利用试验子结构观测数据,在线识别试验子结构的恢复力模型参数,并实时修正与试验子结构有相同恢复力特性的数值子结构恢复力模型。不同试验工况下试验结果对比表明:即使试验子结构数量受到限制,在子结构拟动力试验过程中,基于最小二乘法模型修正方法可以显著提高子结构拟动力试验的精度。

Model Updating Method for Substructure Pseudo-dynamic Test

Taking a shear model and a frame model with buckling-restrained brace as examples, the effect of substructure number on substructure pseudo-dynamic test results was investigated based on time-history analysis using finite element analysis software OpenSEES. It shows that along with the proportion of experimental substructure increasing, the accuracy of test results gradually improves Proportionally. For a structure system consisting of many structure members, the accuracy of substructure pseudo-dynamic test with a small portion of experimental substructure is very limited, which causes test not too meaningful. To improve the accuracy of test, OpenSEES based, virtual pseudo-dynamic substructure tests were conducted to simulate the seismic response of a single-bay two-story frame with diagonal bracing, in which the hysteretic model of experimental substructures is identified on-line based on least square method and model of the part in numerical substructures which has the same hysteretic behavior with the experimental substructure is updated on line. The comparison of test results under different conditions shows that the accuracy of substructure pseudo-dynamic test will be improved by using model updating method based on least square method even with a limited number of experimental substructures.