Baseline-free damage localization method for statically determinate beam structures using dual-type response induced by quasi-static moving load

Structural damage could be localized through comparing the quasi-static moving load induced response before (taken as baseline) and after damage. However, it is very difficult, if not impossible, to obtain the baseline (information from the undamaged structure) for some structures. On this hand, structural response in damaged state only is not sufficient for such methods. On the other hand, only single type response (acceleration, strain or displacement) is employed for moving load based damage localization, i.e., multi-type response is inefficiently utilized. In this paper, a baseline-free damage localization method for statically determinate beam structures is proposed by using dual-type response (strain and displacement) excited by quasi-static moving load. It makes full use of the property that local damage causes no change on the static strain response of statically determinate beam structures except the damaged regions. The baseline displacement response in undamaged state is estimated through the strain response in damaged state. Then the measured displacement response in damaged state is compared with the estimated baseline displacement response, and the area change of the zone encircled by the displacement response and each sub-region (ADRC) is calculated to localize damage. Only the strain response and the displacement response in damaged state are required, and their comprehensive utilization avoids the need for a baseline. Numerical and experimental studies are conducted to investigate the feasibility, effectiveness, and limitations of the proposed method.