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结构非线性恢复力可直接描述其在动力荷载作用下损伤发生发展过程,传统的基于特征值抽取的结构识别方法严格来讲不适应于振动过程中出现损伤的情况。该文利用结构动力响应时程的切比雪夫多项式表示非线性恢复力,在结构质量等物理参数和恢复力模型未知时,提出利用最小二乘优化算法的多自由度结构在完整及非完整激励下非线性恢复力识别方法。对一个含磁流变阻尼器的多自由度数值模型和一个带磁流变阻尼器的四层框架结构的非线性恢复力进行了识别,在数值模拟中探讨了测量噪声对识别结果的影响,并与基于幂多项式模型的方法的结果进行了对比。结果表明,所提出的非线性恢复力识别方法能对结构的非线性恢复力进行有效识别,识别精度高,可用于工程结构在强动力荷载作用下的损伤发生发展过程的监测与识别,并对结构耗能进行定量评估。
The nonlinear restoring force of structure can directly describe the development process of damage under the action of dynamic load. The traditional structure identification method based on eigenvalue extraction can not strictly meet the condition of damage during vibration. In this paper, Chebyshev polynomials of structural dynamic response time series are used to represent nonlinear restoring force. When the physical parameters such as structural quality and the restoring force model are unknown, the multi-degree-of-freedom structure using the least-squares optimization algorithm is proposed for complete and incomplete excitation Lower nonlinear restoring force identification method. The multi-degree-of-freedom numerical model with a magnetorheological fluid damper and the nonlinear restoring force of a four-story frame with a magnetorheological damper are identified. In the numerical simulation, the influence of the measurement noise on the recognition result is discussed. And compared with the result of the method based on the power polynomial model. The results show that the proposed method can effectively identify the nonlinear restoring force of the structure and has high recognition accuracy. It can be used to monitor and identify the damage and development of engineering structures under strong dynamic loads. Structure energy consumption for quantitative assessment.