Finite element modeling of Balsa wood structures under severe loadings

• A constitutive law for Balsa wood used in passive security structures is proposed.
• All important characteristics of its behavior are taken into account.
• Viscoplasticity is modeled by the consistency model of Wang, Sluys and De Borst.
• All the features are detailed since characterization tests until implementation points.
• Validation is based on a very large number of representative static and dynamic tests.

In order to compute, in various situations, the requirements for transporting packages using Balsa wood as an energy absorber, a constitutive model is needed that takes into account all of the specific characteristics of the wood, such as its anisotropy, compressibility, softening, densification, and strain rate dependence. Such a model must also include the treatment of rupture of the wood when it is in traction. The complete description of wood behavior is not sufficient: robustness is also necessary because this model has to work in presence of large deformations and of many other external nonlinear phenomena in the surrounding structures. We propose such a constitutive model that we have developed using the commercial finite element package ABAQUS. The necessary data were acquired through an extensive compilation of the existing literature with the augmentation of personal measurements. Numerous validation tests are presented that represent different impact situations that a transportation cask might endure.