Actuating Connections for Substructure Damage Identification and Health Monitoring

Abstract

Vibration-based damage detection and localization are often performed aiming to relate modal analysis’ results with appropriate metrics that express structural damages. The problem of structural damage identification is generally formulated as an inverse problem aiming to detect changes encountered on the global stiffness matrix of the structure’s model. In most cases, the measured quantities are less than the damage parameters to be identified, thus an infinite number of possible damage configurations is expected to satisfy the measurements. Therefore, damage identification problems are often proven to be ill-conditioned. In addition, as in situ measurements are interpreted by a computer model, a number of uncertainties play an important role in the success of the identification procedure. The class of uncertainties consist of model, discretization, material and measurement errors. Furthermore, a large number of parameters need to be identified in order to assess arbitrary damage scenario and time consuming structure monitoring need to be implemented. In the majority of the developed methods the tendency is to use measurements from sensors while the vibrations are caused either by random (e.g. wind, earthquake etc.) causes or from force actuators in one or more points of the structure. In this work the implementation of actuator connections that divide a structure in several substructures is proposed. These connections can be installed on the structure during construction or retrofit. As it will be demonstrated, these connections can be controlled and excite each substructure separately and record its fundamental frequencies. In this way, each substructure can be monitored in arbitrary time while the complexity and often ill-conditioning of damage localization for large structures can be drastically reduced.