When NASA builds a spacecraft, materials engineers at the agency have the important task of assessing the structural properties of the hardware, whether it’s the hull of a crew capsule or the external tank of a rocket. By knowing these properties, they can ensure that these spacecraft and structures are safe for flight, which means determining if existing defects, such as cracks, will cause structural failure. To perform the work, engineers first have to determine each material’s fracture toughness—its ability to resist fracture when it contains a crack.
Determining a material’s fracture toughness entails running physical tests then performing nonlinear finite element analysis, which requires expertise in several niche fields. “Traditionally, you had to have somebody specifically skilled in nonlinear fracture mechanics and material behavior, and he or she needs to run an analysis of that test, which takes a long time and costs a lot of money,” says Phillip Allen, a materials engineer and structural analyst at Marshall Space Flight Center. As a workaround, he
developed Tool for Analysis of Surface Cracks, or TASC, which was released in January 2014. The free and open source software is easy enough for a technician to use and cuts the time needed for analysis from hours to minutes.
TASC has applications beyond ensuring a spacecraft’s structural integrity. For example, petroleum companies need to monitor their pipelines; the same goes for state and municipal governments and their bridges, overpasses, and other infrastructure. So far the program has attracted 670 users from 60 countries.
In recognition of his work, Allen was one of two recipients of NASA’s prestigious Software of the Year Award for 2014. Now he’s working toward what could be another success story: getting TASC designated as an official standard analysis tool for surface crack testing by the American Society for Testing and Materials.