Radar-based impact load prediction for damage mitigation of infrastructure

The application of smart control technology to both aging and new infrastructure is essential to extending service life, increasing life safety, and decreasing repair and replacement costs. One area of control technology research for civil engineering structures that has received little attention historically is that of high-impact loads, such as collision events. The dissipation of impact energy using smart control devices, such as magnetorheological (MR) dampers, leads to less plastic deformation and damage, and a lower likelihood of collapse in civil engineering structures. Due to the short duration and high variability in magnitude of potential impact loads, the issue of sub-optimal controller performance arises. In order to boost controller performance and improve the effectiveness of the control system, a radar-based impact load identifier is proposed. This radar-based impact load identifier will be used to estimate impact loads from imminent impacting objects, for example vessels and trucks, thus providing input information to the control system before the impact actually occurs. This paper presents the characterization and validation, through laboratory tests, of one part of the radar-based impact load identifier, the range and velocity estimation of the incoming moving objects. The range and velocity information are then used to direct structural control based on laboratory impact tests. An ultrawideband monostatic pulsed radar is used for range and velocity measurements of a laboratory-scale impacting vehicle. The range and velocity measurements obtained from the radar scans are verified using physical measurements and control testing. The tests showed great accuracy for both range and velocity with less than 3% error for each measurement and demonstrated structural control based on these measurements. It is shown from control system testing that the proposed approach is effective in reducing the structural impact responses by 11–30%, depending on the performance index, for pre-impact structural stiffening with passive control of MR dampers.