Applications of the Material Modeling Approach to Airframe Structure

The rapid increase in computing resources throughout the industry is enabling a digital transformation unlike anything preceding it. Every stage from concept to production is being digitized and working with digital twins is gradually becoming the industry norm. ‘Smarter Testing’ methods where virtual testing using digital twins to gain insight precedes actual physical testing are invaluable in minimizing the amount of expensive physical testing that is required.

Since all structural failure essentially starts with local material failure, a thorough characterization of the damage/failure criteria is necessary before implementation in simulation models. Moreover, by empowering the simulation model itself to make key decisions on material damage/failure, a significant increase in predictive capability is enabled.

To enable this predictive capability, simulation methods have been developed at Boeing that employ a material modeling approach. In this approach, material properties that can be obtained from simple coupon tests are generalized for 3-D application using the principles of continuum mechanics. Algorithms for failure initiation and propagation are encapsulated into ‘material subroutines’ that can be interfaced with commercial finite element analysis software such as ABAQUS. Stress analysts can then utilize the modeling capabilities of ABAQUS, together with customized material subroutines, to predict the strength of airframe structure in a highly generalized manner.

The presentation will include details of these methods as well as demonstration for various production applications. In all these cases, the material modeling approach is seen to provide solutions that are beyond the scope of conventional simulations, thereby demonstrating its value at the airframe structural level.