弹性试件的实时子结构试验等效力控制方法

等效力控制方法用反馈控制代替迭代过程求解实时子结构试验隐式逐步积分方法的非线性方程。通过对具有弹性试件体系的数值模拟和试验进一步验证实时子结构试验等效力控制方法的有效性。首先介绍实时子结构试验等效力控制方法的原理;然后以一单自由度体系为例介绍比例-微分等效力控制器的设计方法,并用劳斯判据分析反馈控制系统的稳定性;接着对一具有弹性试件的单自由度体系进行单步输入反应、自由振动反应和受迫振动反应的数值模拟;最后通过对具有弹簧试件的单自由度体系的单步输入、自由振动和受迫振动反应的实际试验验证此方法的有效性。分析结果表明,只要反馈控制系统中各参数均选正值此系统就是稳定的。数值模拟和试验的结果都表明,等效力控制方法可以取得非常好的稳定性和精度。

Equivalent force control method for real-time substructure testing of an elastic specimen

The equivalent force control (EFC) method replaces the mathematical iteration with a force feedback control loop for solving nonlinear equations of motion in a real-time substructure test (RST) using implicit integration algorithm. In this paper numerical simulations and actual tests of structures in which the elastic element was used as the experimental substructure are introduced to further validate effectiveness of the EFC method. Firstly, the EFC method is introduced. Then, one single-degree-of-freedom (SDOF) system is used as an example to introduce the design method of the proportional-derivative equivalent force controller, and its stability is analyzed with the Routh stability criterion. Furthermore, numerical simulations of step, free-vibration, and forced-vibration responses of a SDOF system, in which the elastic element was used as the experimental substructure, are introduced. Lastly, actual RSTs of step, free-vibration, and forced-vibration responses of structure, in which the spring was used as the specimen, are introduced to further validate the effectiveness of the method. The analytical result shows that the feedback control system is stable as long as all control gains are positive. The numerical and experimental results show that the EFC method may exhibit excellent performance in terms of stability and accuracy.