APPLICATIONS OF SYNCHRONOUS STRAIN HAMMER FOR MULTI-SCALE RESPONSE RECONSTRUCTION

摘要

Owing to the economic cost associated with data acquisition and additional practical reasons,the number of sensors is always limited compared with the large scale of structures.To successfully monitor a structure,responses are often required at all of its critical areas,although situations may exist in which the desired locations are not accessible for measurements during its operation.Thus,response reconstruction at those key structural locations where sensors are not available is essential to achieving the structural health monitoring(SHM)objectives.Moreover,multiple types of damage can occur simultaneously in the structures,including the local and global damage.To obtain accurate damage detection results,multi-scale measurements are requited.In view of these,multi-scale response reconstruction at the critical locations of the structures using the measurements is paramount importance to effectively identify the structural damage.A method of multi-type sensor optimal placement for multi-scale response reconstruction has been proposed recently by the authors,including accelerometers,displacement and strain measurement sensors.Experimental investigation is further conducted.Due to the limitation of experimental equipments,two data acquisition systems are employed in experiments,causing nonsynchronous responses.However,the synchronization of responses is required in the integrated responses reconstruction.Therefore,this paper designed a synchronous strain hammer to realize the synchronization of the strain,displacement,and acceleration responses.The synchronous three types of responses are integrated to reconstruct the multi-scale responses at the locations without sensors.The reconstructed responses match well with the measured ones.The results show that the designed synchronous strain hammer is feasible and efficient.