RESEARCHER DEVELOPS NEW SENSOR THAT PROVIDES EARLY WARNING OF BRIDGE DAMAGE A new prototype sensor that provides an early warning signal if a bridge is at risk of scour—the number-one cause of bridge collapse globally— has been developed by a Queen’s University Belfast researcher. Scour is erosion of riverbeds and banks, which can cause major bridge structural failure problems. Dr. Myra Lydon has been working on a sensor since 2021 to tackle the problem. An initial prototype sensor has been developed in partnership with Somni Solutions Ltd. The project was funded by UK Research and Innovation’s Impact Acceleration Accounts (IAA) and Invest NI has provided additional funding for market exploration. Lydon explained the significance of the new sensor, saying, “In 2019 it was estimated that within the UK an average of 8.2 million passenger journeys are lost annually due to the risk of bridge scour, with an associated economic cost of £60 million.” Citing a 2009 catastrophic bridge failure in Malahide, County Dublin, where scour failure occurred suddenly, she added, “With scour, there is often no prior visible sign of distress to the struc- ture. In Malahide, the bridge was inspected just weeks prior to its collapse and had passed inspec- tion but then failed seconds after a full passenger train crossed. Thankfully, it narrowly avoided the catastrophe. “It is vital that we protect our bridges and are able to detect scour before incidents like this take place. The sensor that we have developed detects changes in the riverbed prior to the damage occurring on the bridge. This can provide an early warning, which undoubtedly is safer and helps to prevent widespread bridge failures when we are faced with extreme climate events, such as flooding.” Initial laboratory and field trials have been completed, and Lydon is working with Kris Campbell Head from the Highway Structures Unit in the Northern Ireland Department for Infrastructure to identify a suitable bridge test site. The sensor will be installed along with other structural health moni- toring equipment to ensure the safety of aging bridges. TINY ROBOTS INSPIRED BY ORIGAMI HAVE POTENTIAL USES FOR MATERIALS TESTING Origami principles can unlock the potential of the smallest robots, enhancing speed, agility, and control in machines no more than a centimeter in size. At University of Michigan, researchers have demonstrated that behavioral rules underpinning the Japanese art of folding can expand the capabili- ties of these machines, creating potential for greater use in fields as diverse as medical equipment, infra- structure sensing, and materials testing at a mass scale. “We’ve come up with a new way to design, fabri- cate, and actuate microbots,” said Evgueni Filipov, assistant professor of civil and environmental engi- neering. “We’ve been the first to bring advanced origami folding capabilities into one integrated microbot system.” Their bots can form one shape, complete a task, then reconfigure into a second shape for an addi- tional task, and so on. The latest research from the team, which includes Kenn Oldham, a U-M professor of mechanical engi- neering, PhD student Yi Zhu, and graduate research assistant Mayur Birla, appeared in Advanced Functional Materials. SCANNER Bridge scour—the erosion of riverbeds and banks—can cause major bridge structural failure problems. 10 M AT E R I A L S E V A L U AT I O N • J A N U A R Y 2 0 2 3 2301 ME Jan New.indd 10 12/20/22 8:15 AM

To date, most microbots have limited movements, which hampers their ability to perform useful tasks. To increase their range of motion, they need to be able to fold at large angles. U-M’s team has created microbots that can fold as far as 90 degrees and more. Larger folds allow microbots to form more complex shapes. U-M’s approach enables its microbots to complete their range of motion up to 80 times per second, a faster pace than most can operate. Microbots using origami principles often require an outside stimulus to activate, such as heat inside a body or a magnetic field applied to the microbot. U-M’s utilize a layer of gold and a layer of polymer that act as an onboard actuator—meaning no outside stimulus is needed. While the microbots are currently controlled by a tether, eventually, an onboard battery and a microcontroller will apply an electric current in the systems. “When current passes through the gold layer, it creates heat, and we use heat to control the motions of the microbot,” Filipov said. “We drive the initial fold by heating the system, then we unfold by letting it cool down. “To get something to fold and stay folded, we overheat the system. When we overheat, we can program the fold— change where it comes to rest.” These capabilities allow microbots to function elastically and plastically—giving them the ability to recover their original shape. The research was supported by the Defense Advanced Research Projects Agency and the U-M College of Engineering Dean’s Fellowship. INDUSTRYNEWS | SCANNER Yi Zhu, Graduate Student Research Assistant for Civil and Environmental Engineering, tests a new generation of microrobotics inside Evgueni Filipov’s lab at the University of Michigan. A new generation of microrobotics is based on the principles of origami. DATAFACTS | NDE METHODS FOR BRIDGE INSPECTION The Annual State Bridge Engineers Survey (2018)* conducted by the AASHTO Subcommittee on Bridges and Structures found that the most often recommended NDE methods for estimating delaminated areas for partial depth removal were chain drag (33%), ground penetrating radar (26%), and thermal/infrared testing (19%). *based on 42 respondents more than one method could be selected . Source: Annual State Bridge Engineers Survey (2018), AASHTO Subcommittee on Bridges and Structures 17 (19.1%) Thermal/Infrared Testing (IR) 23 (25.8%) Ground Penetrating Radar (GPR) 10 (11.2%) Impact Echo 29 (32.6%) Chain Drag 3 ( 3.4%) Half-Cell Potential 1 ( 1.1%) Electrical Resistivity 2 ( 2.2%) Ultrasonic Surface Waves 4 ( 4.5%) Other/no reply J A N U A R Y 2 0 2 3 • M AT E R I A L S E V A L U AT I O N 11 2301 ME Jan New.indd 11 12/20/22 8:15 AM