土-结构-流体动力相互作用的实时耦联动力试验

针对振动台试验中无限地基难以模拟和数值分析中流-固耦合作用难以计算两个难题,将最近发展的实时耦联动力试验方法引入土-结构-流体动力相互作用问题的研究。以一个渡槽结构为例,其中渡槽-水体作为物理子结构,采用振动台进行物理试验,而无限地基作为数值子结构,采用集总参数模型进行数值模拟。两个子结构之间实时交换数据,联合评估整个耦合体系的动力响应。试验结果和有限元数值模拟结果吻合良好,表明该试验方法具有较高精度。对不同特性地基土进行的试验对比分析结果表明:对于软土地基,考虑土-结构相互作用(SSI)的结构反应幅值明显减小,周期延长;随着地基土变硬,SSI效应逐渐变弱,结构反应最终收敛至刚性地基解。

Real-time dynamic hybrid testing for soil-structure-fluid interaction analysis

In traditional shaking table test semi-infinite foundation is difficult to consider; whereas in numerical simulation dynamic fluid-structure interaction is hard to calculate. To deal with the two difficulties, a newly developed real-time dynamic hybrid testing method is employed to solve the dynamic soil-structure-fluid interaction problems. Taking an aqueduct for example, the aqueduct-water system, called experimental substructure, is physically tested on a shaking table; while the semi-infinite foundation, called numerical substructure, is numerically modeled by a lumped-parameter model. The data exchange between the two substructures is performed in real-time; thus the dynamic response of the whole coupled system can be evaluated. Meanwhile, the finite element analysis is also implemented to simulate the test model. The comparison of the tested results with those obtained from the finite element analysis demonstrates that the real-time dynamic hybrid testing can achieve good test accuracy for this dynamic interaction problem. The tests of the soil-structure interaction (SSI) effects for different soils show that the soft soil reduces the structure response amplitude and extends the response period. With soil becoming hard, SSI effects decrease and the structure responses will ultimately converge to the solutions of rigid foundation.