NIST failure simulation strategy helps find crack initiation point in airplane wing materials

April 20, 2017
Source: ASM International

NIST, Gaithersburg, Md., announces that a team of researchers including NIST scientists has found a way to improve the process of simulating the onset of failure in materials for airplane wings. Understanding this initiation point is critical for predicting when and how wings fail. Their method shows designers how to put a very small sample through a series of stress scenarios to efficiently determine the amount of stretching that will cause it to break. The approach could help address one of the key factors that reduces the effectiveness of simulations: uncertainty in their prediction of the wing's strength.

The team's idea is to simulate deforming a tiny bit of material by increasing amounts and make it possible to save the state of the simulation at any given point. The advantage of state-saving, says NIST physicist Paul Patrone,  is that you can see what happens if the material is allowed to relax.

"It's kind of like taking the material down a road with different forks and looking at what happens down each one," he said. "We pause the simulation at different points along the way and ask, 'If I stopped trying to bend this, what would happen? Would it stay bent, or bounce back to its original shape?' We have the ability to explore all these forks, which allows us to more precisely state when the material was first damaged."

Because a new jumbo jet can run up several billion dollars in development costs, such improvements can help companies trust the reliability of their modeling approaches before committing to more expensive steps involving real-world materials.

"Our approach provides a new 'signal' for a material's breaking point that will hopefully improve the reliability of the simulations," adds Dr. Patrone."It also allowed us to statistically quantify our confidence in their predictions. We need that, if simulations are to be used as a proxy for experiments."



Subject Classifications

Composite Materials

Industries and Applications | Aerospace and Defense

Materials Testing and Evaluation | Computational Materials Engineering