基于实时仿真补偿的高性能振动台子结构实验技术研究

Real time dynamic sub-structuring (RTDS) testing combines the advantages of numerical simulations and physical tests, which supplies a new method for the experimental investigation for structure dynamic performance. Shaking table RTDS is a key branch of RTDS because of its potential for testing the integral dynamic behaviour of structure. However, because of the coupling effect between structure and table, the testing capability of shaking table RTDS for high frequency and nonlinear behaviour of large scale specimen is limited. Thus, shaking table RTDS can only test the structure with a mass much less than table. This cannot satisfy the needs of the research on earthquake-resistance of super-high rise and long-span structure and the multi medium coupling in engineering structure. This research focus on the shaking table RTDS taking the upper part as physical structure. Firstly, the numerical model to describe the whole process of shaking table RTDS is planned to build. And then the effect of STI on the stability and accuracy shaking table RTDS is intended to analyse scientifically using control theory. After that, a dual function control strategy will be developed combining real-time simulation technique and adaptive control algorithm to compensate the coupling effect between structure and table, therefore the stability and accuracy of shaking table RTDS can be enhanced, so that the application of shaking table RTDS may be enlarged. Finally, the efficiency of shaking table will be validated in the application of SSI simulation. This research will make it possible to test large specimen with high order and nonlinear behaviour using shaking table RTDS and therefore has a good prospect of application.

动力子结构实验技术融合数值计算和物理试验的优点，为工程结构试验研究提供了新的试验手段。振动台子结构实验技术能对结构整体动力特性进行全面模拟，是子结构实验技术发展的重要方面。试件与振动台耦合效应限制了振动台子结构实验技术对高频特性、非线性特性、大尺寸试件的模拟能力。目前只能进行质量远远小于台面的低频率物理子结构试验,无法满足超高层、大跨度、多介质耦合的工程结构抗震研究需求。本课题以大尺寸试件振动台动力子结构实验为研究对象，建立振动台子结构系统全过程模型，基于系统控制理论分析试件与台面耦合效应对振动台动力子结构实验稳定性和精度的影响，结合实时仿真与自适应控制理论建立两阶段控制策略，全过程补偿试件与台面耦合效应，以增强振动台动力子结构试验稳定性和精度，提高振动台子结构实验应用范围，并通过土结相互作用试验验证其有效性。本课题将为大尺寸试件高阶及非线性特性模拟提供新的试验手段，具有很好的应用前景。

为了确保能顺利、准确的实现试验，振动台子结构试验需要面临的最大挑战在于设计高稳定性、高保真度的控制器，以便充分补偿振动台动力特性，提高实验技术的精度和应用范围。但在进行物理子结构试件较大的试验时，振动台动力特性与物理子结构动力特性相耦合，极大的限制了振动台子结构实验系统精度和应用范围（可试验试件频率较低、质量较小）。本项目研究目标在于对试验试件与振动台耦合动力特性进行实时补偿，以消除试件与台面相互作用的影响，扩宽振动台子结构试验频带，提高振动台子结构实验系统对高频特性、大尺寸试件的试验模拟能力。取得如下成果：（1）基于增益裕度提出了多自由实时子结构试验系统稳定性综合分析方法，分析了加载系统与试件相互作用、数值计算方法以及结构非线性对系统稳定性的影响。（2）将逆动力补偿和全状态反馈相结合基于实时仿真技术提出了基于仿真的全状态子结构试验控制方法。该方法能同时补偿加载系统相位滞后和幅值误差，极大的提高了系统稳定性和试验精度。（3）将该方法用于子结构试验，成功实现了土-结相互作用、储罐隔震性能以及TLD减震性能的大尺寸子结构试验。