Infrastructure protectionMood ring materials offer a new way to detect damage in failing infrastructure

“Mood ring materials” could play an important role in minimizing and mitigating damage to the U.S. failing infrastructure.

The American Society of Civil Engineers has estimated that more than $3.6 trillion in investment is needed by 2020 to rehabilitate and modernize the nation’s failing infrastructure. President-elect Donald Trump has promised to establish a $1 trillion infrastructure improvement program when he takes office.

An important element in any modernization effort will be the development of new and improved methods for detecting damage in these structures before it becomes critical. Vanderbilt says that thisis where “mood ring materials’ comes in.

Sprinkle a pixie dust of nanoparticles into a batch of clear polymer resin and you get “a smart material that changes color when it is damaged or about to fail, what I call a ‘mood ring material,’” explained Cole Brubaker, a doctoral student in civil engineering who is part of an interdisciplinary research team at Vanderbilt University’s Laboratory for Systems Integrity and Reliability (LASIR) developing the new sensing system.

Smart sensing technologies are one of the hot new fields in civil, mechanical and aerospace engineering. These efforts have generally focused on developing networks of physical sensors that are attached to structures of interest. However, this approach has been hindered by high cost as well as power and data processing requirements.

The LASIR researchers are taking a different tack by incorporating fluorescent nanoparticles into the material itself that react to stress by changing their optical properties in order to create a new kind of detection system that can monitor these structures in an efficient and cost-effective fashion.

“Currently, there are two ways to keep everything from bridges to aircraft safe,” said LASIR Director, Douglas Adams, Daniel F. Flowers Professor of the civil and environmental engineering. “One is to send people out to look at them with a flashlight. The problem with this is that it is labor-intensive and the people can’t see very small cracks when they form. The other is to install elaborate sensor networks that constantly look for small cracks and detect them before they grow too large. The problem is that these networks are very expensive and, in the case of aircraft, add a lot of weight. “So we need to somehow change the materials we are using so they illuminate these tiny cracks.”