To do this, her research group investigates the nonlinear properties of geo-materials such as rocks and sand stones, which have beneficial properties she aims to replicate in new material design. The irregular shapes in these materials due to cracks and grain structures give them highly nonlinear mechanical properties that have been exploited in nondestructive evaluation techniques; however, Matlack thinks these properties could be useful in many other applications. She aims to use these features to design new materials with beneficial dynamic properties like responsiveness to harmonic excitation or impacts, in addition to beneficial static properties such as strength, durability, and load-bearing capabilities.
Matlack’s lab tests the dynamic properties of materials using ultrasonic transducers and laser vibrometers, as well as their mechanical properties using tensile tests and fracture toughness tests. “We basically excite the material at different frequencies and measure its response, and our goal is to engineer that response,” said Matlack. Part of the grant will help purchase new equipment, although her lab already contains most of what is necessary to conduct the research.
The idea for the project stemmed from a combination of different areas Matlack already studies: the use of ultrasound to detect damage in materials and the redesign of structures to control how mechanical waves propagate through them. Now, the focus is on designing new materials with the behaviors she has analyzed in her previous research.
The new materials could be used for protective equipment, such as armor or components of vehicles or aircrafts. Instead of adding extra elements or active mechanisms to give a desired property, they could be designed into the material itself.
ARO is an element of the U.S. Army Combat Capabilities Development Command’s Army Research Laboratory. The grant is co-funded by two programs at the ARO – the Complex Dynamics and Systems branch and the Solid Mechanics branch. “I think this will be really beneficial because of the combination of different programs and getting to interact with various people in ARO. We’ll be able to tailor our work to be very relevant to multiple programs,” Matlack said.
“Through some clever reasoning about ultrasonic interrogation of cracks and irregularities geo-materials, Dr. Matlack has developed a compelling basic research vision that might transform future protective structures,” said Dr. Samuel Stanton, ARO program manager. “Time and some clever scientific work will tell, but it could soon be the case that what many might have dismissed as utterly mundane (it is, after all, rocks) was quietly holding the key to the types of breakthroughs the Army needs to maximally protect Soldiers.”
The Young Investigators Program supports outstanding young university faculty members pursuing fundamental research in areas relevant to the Army while encouraging their teaching and research careers. YIP awards are funded up to $120K per year for three years.