Progressive damage detection using non-contact measurements

This paper presents work in progress toward the development of a bridge condition assessment system. The system combines remote laser vibration sensing technology and a strain-energy-based damage detection algorithm. The results from vibration tests conducted on laboratory specimens with different degrees of damage are presented. The vibration signatures are acquired using Scanning Laser Vibrometers (SLV). The extracted mode shapes fi om these tests are then used in the damage detection algorithm. The preliminary results indicate that the strain energy differences are highly sensitive to damage, and can be used to locate and distinguish progressive damages. The combination of SLV technology and the damage detection algorithm makes remote sensing attractive for the monitoring and inspection of structures. Finite element simulation of a progressive damage at a single location is also presented to illustrate the sensitivity of the algorithm to increasing damages.