Real Time Structural Damage Assessment from Vibration Measurements

Damage identification in civil engineering structures using vibration measurements has become an important area of research. A reliable and cost effective method is required to detect and quantify local damage in the structures. The objective of this new proposed method is to identify structural damage in real time at a more detailed level directly from the vibration measurements. Structural damage is assumed to be associated with a proportional reduction of element stiffness matrix. Dynamics characteristics of the structure are calculated by using N ewmark's numerical integration method based on measured acceleration data. The change in the stiffness matrix caused by structural damage is implemented into the equation of motion of the dynamic system. A system of governing equations is derived, where the difference between the vibration data of undamaged and damaged structures can be directly adopted. The changes in the stiffness matrix are represented by the changes in the coefficients associated with element stiffness matrixes. Those coefficients can be used as damage parameters in structural damage detection. Both the location and extent of the damage are then determined based on the inverse calculations of damage parameters of the individual elements. Finally, a numerical example is utilised to demonstrate the effectiveness of the proposed approach for on-line structural damage assessment.