基于神经网络模型的结构参数提取新方法

A NOVEL STRUCTURAL PARAMETER EXTRACTION METHODOLOGY WITH NEURAL NETWORK BASED NONPARAMETRIC MODEL

  • 摘要: 参数识别是结构健康监测、性能评估的关键问题之一。作为一种代表性的动力系统时域参数化模型方法,自回归滑动平均(Auto-regressive and moving average, ARMA)模型在机械和土木工程结构的参数识别中得到了广泛应用;另一方面,尽管一般而言神经网络模型的权重和阈值并不需要具备明确的物理意义,但由于神经网络具有描述复杂函数关系的能力,作为一种非参数化模型方法在结构动力系统的建模和控制领域发挥重要作用。该文首先通过结构运动平衡方程的离散时间解,证明了非参数化神经网络模型与ARMA模型在描述线性结构动力系统的响应时间序列上的等效性,在此基础上,提出了一种从结构的非参数化神经网络模型中抽取结构物理参数的新方法。通过一个多自由度系统的数值模拟结果和一个四层钢框架模型的动力试验实测数据验证了所提出的结构参数抽取方法的有效性。

     

    Abstract: Structural identification has become an increasingly important topic for health monitoring and performance assessment of engineering structures. On one hand, the auto-regressive and moving average (ARMA) model has been widely employed as a typical time-domain modeling method for dynamic systems. On the other hand, with the ability of mapping any complex function and its parallel computation characteristics, neural networks-based identification method has been widely employed as a nonparametric model for civil and mechanical engineering structures even the weights and thresholds in the trained neural network model do not necessarily have clear physical meaning. The equivalence of the two representative time-domain identification methodologies was studied firstly according to the discrete solution of structural dynamic responses. Then, a novel structural parameters extraction methodology was proposed by the use of excitation and dynamic response measurement time series. Finally, the accuracy and efficiency of the proposed approach were validated via a numerical model with three degree-of-freedoms (DOFs), and via a dynamic test on a four-story model structure with impulse excitation. Results show the structural parameters can be extracted from a nonparametric model with neural networks.

     

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