Optimal Sensor Placement Based On Remodeling Innovation

Optimal placement of sensors is the essential task in building system for structural health monitoring.If the structural state information recorded by structural health monitoring system can obtain precise reflection of structural characteristics,to a large extent,depends on sensors that instrumented previously.Therefore,superior placement scheme of sensors is a crucial part for structural health monitoring.The article focuses on the research about issues that exist in the Effective Independence?EI?method.Meanwhile,a new optimal sensor placement method based on remodeling innovation?Remodeling Innovation Method,RIM for short?is proposed.The main researches focus on the following aspects:?1?Making a brief introduction to the theoretical basis of EI method.Then the orthogonality of EI method that implied in each iteration is explained on the basis of reviewing the fast algorithm by QR decomposition for EI method,and the concept of re-orthogonalization of modal in each iteration is introduced.Meanwhile,an in-depth analysis of EI method is done,and it is found that in the computation of the EI method,the sum of each retained row in the eigenvalue contribution matrix is a constant.This potential property can be analyzed by transforming the eigenvalue contribution matrix,and the physical significance of re-orthogonalization of modal in each iteration of EI method can be obviously manifested with this matrix transformation.The physical significance of the re-orthogonalization of the modal in each iteration can be regarded as weighing the modal matrix with the inverse of the eigenvalue matrix i.e.?^-1.?2?Two issues existing in the EI method are discussed based on the theoretical basis of EI method.On the one hand,Kammer proposed that maximization of the trace of Fisher information matrix could be used as criterion for maximizing the Fisher information matrix.However,the maximization of the trace of Fisher information matrix can't be guaranteed by deleting the minimum element in EI coefficient.On another hand,EI method only removes the row with the minimum EI coefficient from the modal matrix in each iteration without considering the influence of the structural mass distribution which alternate with deletion of the degree of freedom.?3?This article puts forward a new optimization method for sensor placement based on remodeling innovation,in order to avoid the influence that in each iteration of EI method only the row with the minimum EI coefficient is removed from modal matrix without considering the influence of the structural mass distribution.The influence of structural mass distribution on the proportion between different elements of modal is fully considered in this new method.Meanwhile,this new method solves the issue that the original modal is no longer orthogonal to the new modal mass in traditional reduced computation.And the superiority of this method is verified by numerical examples.Both RIM and EI method are applied to optimize sensors for numerical examples,and the layout schemes of the two methods are evaluated by criterion.The results show that the layout scheme of RIM is superior to that of EI method.?4?Taking Nanshan bridge in Pingyao town,Yuhang as a practical engineering example,the main bridge of Nanshan bridge is modeled by ANSYS.Then the RIM and EI method are both applied to optimize sensors from 57 candidate points of the main bridge,and the performance of two methods in sensor placement are analyzed and compared.