Modeling microstructures

How a part is made determines its microstructure, which determines its behavior. Scientists at Los Alamos National Laboratory have developed an open-source code that allows researchers to “see” into a part’s microstructure and determine how it might perform under certain conditions. The code, called Fierro, is particularly useful for additive manufacturing, in which microstructures are not always well understood. Fierro evaluates the unique microstructures of additively manufactured parts and simulates how those microstructures impact performance—things like strength, safety, and durability.

“Codes such as these are essential to understanding the relationship between manufacturing processes and part performance,” says Fierro co-developer Nathaniel Morgan. “Adjusting manufacturing processes to give a superior microstructure yields a stronger product. The need to better understand the impact of microstructure on part performance is critical and creates pathways to adopt modern manufacturing methodologies.”

Along with evaluating the microstructures of additively manufactured items, Fierro can design and optimize additively manufactured products. Out of millions of different options, the code autonomously finds the optimal design that meets the requirements set by the user. 

Fierro can also design and model items for stress wave dissipation, which is important for energy-absorbing products such as helmets and car bumpers. “With the advent of additive manufacturing, energy-absorbing structures can be produced with intricate lattices that deliver superior safety and reduced weight,” Morgan says. “Fierro uniquely can identify the optimal lattice to dissipate stress waves, maximizing the efficacy of an energy-absorbing structure.” 

Leveraging the power of supercomputers, Fierro processes problems faster and allows users to develop higher quality simulations with higher levels of accuracy. As Morgan explains, slower running software often forces engineers to make concessions on things like fidelity and physics, which could lead to errors in evaluating performance. 

“Efficiency, which in this case refers to shorter computing times to solve a problem of specific size, is paramount when using Fierro for material design,” says Fierro co-developer Ricardo Lebensohn. “Finding an optimized design requires running expensive models many times over as part of an optimization loop.” 

Morgan and Lebensohn hope Fierro, which is openly available on GitHub, can eliminate, or at least reduce, poorly made parts that could pose serious safety risks.

“Fierro is one of many success stories from the Laboratory Directed Research and Development program,” Morgan says. “This is a high-value research project that we hope can have an impact not just on academia and our profession but the world as a whole.”  ★