动态分布载荷识别中的传感器配置研究

Study on sensor placement for distributed load identification

鉴于含噪声的测量响应数据影响了动载荷识别结果的不足,从结构动力学正问题出发,建立动载荷和动响应之间的关系,探索各阶模态的空间分布规律,提出了基于模态函数分布的响应测量点筛选准则,运用级数分解的思想,推导了响应数据含有噪声工况下的载荷识别算法。与常规的平均选取测量点方法比较,改善了反问题求解时的不适定性,大大提高了计算的精度及算法的稳定性。通过数值仿真,当响应数据受噪声污染严重时,验证了方法的有效性和较强的抗噪性能。最后,将提出的响应测量点筛选准则应用于动载荷识别中的多传感器优化配置中,为准确、高效地识别工程结构上的动载荷做技术铺垫。

In order to deal with the shortcoming of the response data polluted by the measurement noises, which will reduce the accuracy and stability of the identified loads by the technique of inverse analysis, an optimal screening methodology of the measuring points is presented based on mode function distribution to improve the algorithms of the load identification in the working condition of the response data being polluted by noises. The principle of improving algorithms of load identification is established by deriving the mathematical formula between the dynamic load and response from the forward problem of structur al dynamics. The distribution characteristics of the modal shapes is investigated and the idea of orthogonal polynomial series is applied in the present study. The measuring points screened by the proposed methodology show the temporal and spatial distri bution of the dynamic loads with high accuracy. Compared with the conventional method by which the points are screened e qually, the proposed method improves the accuracy and stability and overcomes the ill posed nature of the inverse problem. Numerical simulation is carried out for several cases to prove the validity and good anti-noise ability of this optimal screening method even in the situation of the response data being polluted in high noise level. Finally, the method is applied into the opti real sensor placement for load identification, to provide the technological support for the practical engineering application of dy namic load identification with high accuracy and effectiveness.