Oak Ridge National Laboratory’s exascale Frontier system may be stealing some of the spotlight, but the lab’s 148.6 Linpack petaflops Summit system is still churning out powerful science. Recently, for instance, the supercomputer hosted research studying the structure of carbon fiber in an attempt to make the mass production process easier.
Lightweight and strong, carbon fiber is used from sports gear to airplanes—but it’s expensive to produce. “Carbon fiber is everywhere now, but it’s still costly to fabricate, and the structural details are surprisingly complex,” said Jennifer Niedziela, a physicist at ORNL and co-author of the study, in an interview with ORNL’s Matt Lakin.
So the ORNL researchers set out to make a dent in that cost. “If we can model carbon fiber virtually and translate that modeling to process-monitoring capability,” Niedziela said, “then we can potentially make major improvements in the production process with less time and expense.”
In short, the researchers sought to understand the atomistic dynamics behind carbon fiber’s superb tensile strength-to-weight ratio and, in particular, how defects in the fiber can hinder that dynamic. Typically, this would be studied with Raman spectroscopy (photon bombardment); but for this study, the researchers leveraged Summit to apply density functional theory to the problem, simulating the structure and vibrational properties of a 400-atom carbon fiber cell with two defects.
“As soon as we start incorporating defects, it breaks up the symmetry of our model and requires more calculations to simulate, which means we can’t use the usual approximations and other shortcuts to lower computational costs,” said Sara Isbill, a postdoctoral researchers in ORNL’s Nuclear Nonproliferation Division and co-author of the study. “We couldn’t have done this without Summit.”
The calculations lent a more detailed picture of the defects, paving the way toward even more intense simulations. “We need to better understand the atomic-level structure,” Isbill said. “Eventually, we want to look at these materials under conditions outside their normal equilibrium, such as higher temperature, and see how they respond. This study is a first step toward that.”
“Thinking of carbon fibers as highly defective graphite, these calculations on Summit move us another step closer to being able to simulate a realistic, complex carbon-fiber system at the atomic level and accurately predicting key material properties,” added Ashley Shields, a member of the research and development staff at ORNL and co-author of the study.
To learn more about this research, read the reporting from ORNL’s Matt Lakin here and read the research article here.