In recent years, real-time hybrid testing (RTHT) has been applied for the dynamic testing of high-speed trains running on bridges. A guarantee of stability for the RTHT system is essential to achieve a safe and reliable result. However, the inherent time-varying characteristics of the vehicle-bridge coupled system pose challenges to RTHT stability prediction. This study aims to develop a stability prediction method specifically tailored for time-varying RTHT system. Firstly, the vehicle-bridge coupled RTHT was modelled using a discrete state–space representation with a comprehensive consideration of the time-varying vehicle-bridge interaction and the dynamics of the shaking table. Subsequently, a time-varying stability criterion was derived from the periodic time-varying state matrix, forming the basis for a relative stability prediction method. The validity of the proposed method was confirmed through simulations and experiments employing a single-axle interaction within the vehicle-bridge coupled RTHT system. The coupled system consisted of a quarter-car model and simply supported beams were used as an example to evaluate the stability and accuracy of the time-varying RTHT. The results showed that the stability increased with increasing vehicle speed. Reducing the pure time delay of the shaking table improved both stability and accuracy. Increasing the effective frequency of the shaking table improved the accuracy but may reduce the stability of the RTHT.

中文翻译：

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车桥耦合时变实时混合试验系统稳定性预测方法


近年来，实时混合测试（RTHT）已应用于桥梁上运行的高速列车的动态测试。 RTHT 系统的稳定性保证对于获得安全可靠的结果至关重要。然而，车桥耦合系统固有的时变特性给RTHT稳定性预测带来了挑战。本研究旨在开发一种专门针对时变 RTHT 系统的稳定性预测方法。首先，使用离散状态空间表示对车桥耦合 RTHT 进行建模，综合考虑时变车桥相互作用和振动台动力学。随后，从周期性时变状态矩阵导出时变稳定性准则，形成相对稳定性预测方法的基础。通过在车桥耦合 RTHT 系统中采用单轴交互的模拟和实验证实了所提出方法的有效性。以四分之一车模型和简支梁组成的耦合系统为例，评估时变RTHT的稳定性和精度。结果表明，稳定性随着车速的增加而增加。减少振动台的纯时滞提高了稳定性和准确性。增加振动台的有效频率可以提高精度，但可能会降低 RTHT 的稳定性。