Damage detection of beam structures using quasi-static moving load induced displacement response

Applying signal processing tools on quasi-static moving load induced response to localize damage is extremely promising in the field of structural health monitoring. However, it is still an issue to quantify damage for such methods for the lack of definite correspondence between damage severities and damage indexes they adopted. This paper aims to develop a two-stage method with the ability to quantify structural damages by using the quasi-static moving load induced displacement response. As the displacement response of beam structure caused by quasi-static moving load is in close proximity to displacement influence line (DIL), this paper investigates the correspondence between damage parameters and several DIL related features systematically. Then a damage localization index is defined based on area of the region encircled by the DIL change (DILC) and element (ADE), and a damage quantification equation is established based on the area of the region encircled by the DILC and beam (ADB), respectively. Such a two-stage method can take better advantage of the rich test data provided by moving load test, localize and quantify damage with few sensors rapidly. Numerical and experimental examples are carried out to demonstrate the effectiveness of the proposed method.