基于独立分量分析的多源动态载荷识别方法

提出了基于独立分量分析的多源动态载荷识别方法, 解决了在结构系统未知 的情况下载荷波形的识别问题. 该方法基于结构在多源动态载荷作用下, 其响应是载荷与对 应的结构脉冲响应卷积的原理, 并假设载荷源相互统计独立. 与既有的载荷识别方法相比, 该识别方法特点表现在: 结构质量, 刚度及阻尼等信息可以完全未知, 但以实际 载荷间的独立性为优化目标; 用互信息来度量识别载荷间的独立性, 通过梯度下降算法取消 识别载荷间的各阶相关性, 使识别载荷间基本满足相互独立; 从波形的角度来进行载荷识别. 通过数值仿真表明: 该方法对测点, 噪声, 不同载荷形式及不同结构有较好的鲁棒性; 识别 载荷与实际载荷在归一化条件下, 识别载荷与实际载荷相关性系数约为1.

AN IDENTIFICATION METHOD OF MULTI-SOURCE DYNAMIC LOADS BASED ON INDEPENDENT COMPONENT ANALYSIS

This study proposes an identification method of multi-source dynamic loads based on independent component analysis,in order to detect the wave pattern of the load subjected to a structural system whose configurational information is totally unknown.The method is based on the principle that the response of structure is a convolution of load and corresponding structure impulse response;also,it assumes that individual load sources are statistically independent to each other.When compared with the existing load identification methods,the features of the method developed in this study embody three merits:(1) The structural configuration, such as distribution of structural mass,structural stiffness and damping ratio,could be unknown,and the independence among the actual loads is taken as the goal of optimization;(2) The independence of individual identified loads is measured using their mutual information,and the correlation at different orders is eliminated by the use of gradient degressive algorithm,so that the independence among detected loads is guaranteed; (3) Loads could be identified from the standpoint of wave patterns.Numerical simulation indicates that the algorithm is robust on measuring point,noise,structure and input load.By normalization,the value of the correlation coefficient between identified and actual loads is approximately 1.Therefore,this method successfully integrates the existing knowledge on load into the load detection algorithm,and could make a confident estimation of the actual value,which contributes in the practical significance of the developed method.