Developing algorithms to detect damage on smart structures

When one thinks of “futuristic research,” two of the most common associations made are in the realms of space travel and virtual reality. Mohammad Jahanshahi, associate professor of civil engineering, is conducting research on both topics.

Jahanshahi is a member of Purdue University’s Resilient Extra-Terrestrial Habitat Institute (RETHi) led by Professor Shirley Dyke. Established in 2017, the multidisciplinary effort seeks to establish habitats on other extra-terrestrial locations such as Mars and the moon and pursue three research thrusts: anticipating and adapting to possible threats; building networks of sensors that can actively learn, detect and diagnose issues; and developing autonomous robots that can operate independently and collaborate with humans.

Jahanshahi’s current research involves developing artificial intelligence algorithms for damage detection on smart structures. To this end, he is working on a geodesic dome — which his team assembled and  instrumented with accelerometers — and using structural dynamics and machine learning to detect when damage occurs to the structure.

The dome, Jahanshahi said, acts as a scale model that would protect the extra-terrestrial habitat within it. Through a series of hammer tests (literally striking the structure with hammers at various points and with varying force), the sensors measure the vibrations and record and report the damage sustained.

“This is a very challenging problem as we’re collecting data that isn’t just ‘plug-and-play,’” Jahanshahi said. “We need to have a strong computer to collect up to 200 different data points from these accelerometers. It must then assess the amount of damage sustained, pinpoint exactly where it occurred and issue a report so that repairs can be made.”

Aiding in the data collection are civil engineering undergraduate researchers Harrison Kuszmaul and Wonsang Cho.

“It’s been a challenging process as we are doing something that really hasn’t been done before,” Cho said.

Kuszmaul echoed Cho, adding that while this has been a challenge, it has also been a rewarding and exciting endeavor and he looks forward to where the project leads.

“When I heard about RETHi, I knew this was something I wanted to be involved with,” Kuszmaul said. “We’re working toward a future where people can live in outer space — and it’s being done right here, right now, at Purdue.”

Jahanshahi said the next phase in their research will be to perform damage assessment on a new cyber-physical testbed that will be assembled within Herrick lab his summer.

INDOT Assistant Statewide Maintenance Operations Engineer Andrew Blackburn (left) tests the VR module with Purdue civil engineering PhD student Yu-Ting Huang.

Using virtual reality to identify inconsistencies in bridge inspectors

In the realm of more Earthly damage assessments, Jahanshahi’s research team is developing a virtual reality training program for the Indiana Department of Transportation’s (INDOT) bridge inspectors.

“Bridge inspection is vital to ensure safety — but there is a huge inconsistency among different inspectors due to the subjectivity of the task,” Jahanshahi said.

His team is working on generating high-resolution, 3D models of bridges that can be pushed into a VR headset and allow bridge inspectors to assess the structure in an immersive photo-realistic environment. Then, INDOT can evaluate the performance of different inspectors and update the training procedures.

“These VR modules allow inspectors to experience something much more immersive than observing a broken structure,” said Yu-Ting Huang, a doctoral student in civil engineering. “You can see the structure from all angles in greater detail than from limited views afforded from on-site visits.”

VR modules also create a higher degree of uniformity in both training and damage assessment, Jahanshahi said.

“When it comes to bridge inspections, there is an unavoidable degree of subjectivity to it,” he said. “Two inspectors can have two completely different responses when coming across a small crack. With this program, you can create a checklist and score the assessments, which will lead to greater uniformity amongst inspectors in the future.”