Numerical Simulations of Dynamic Deformation of Air Transport Package PАТ-2 in Accidental Impacts

The PAT-2 package is designed by Sandia National Laboratories [1] for the safe transportation of plutonium and/or uranium in small quantities, especially as transported by air. The package consists of an outer container and an inner absorber. The outer container is made of 304 stainless-steel sheet metal. The inner absorber assembly consists of redwood and maplewood layers and is used for decreasing the mechanical loads onto the inner capsule with a radioactive material. The PAT-2 package is resistant to high-speed jet aircraft crash. That was verified by the experiments. The package was tested in several orientations and subjected to impacts at a velocity of >129m/s onto a flat unyielding surface. Some obtained results of the package dynamic deformations are described in [1]. It is also noticed in [1] that the worst impact orientation could not be proven by the stress analysis before the tests. That’s why it’s very important to conduct a numerical simulation of the package behavior in high-speed impacts to compare the numerical results with the experimental data. Such a numerical expertise opening “an internal deformation world” of the construction behavior allows understanding the weakest and the strongest features of the design and can show the ways on how to improve the structure. It’s also an additional experience of LS-DYNA® applications for such problems as well. The computer model description and the numerical calculations results of the dynamic deformations of the package subjected to top-end, bottom-end, top-corner, bottom-corner and side impacts at a speed of >129 m/s are presented in the paper. Furthermore, U.S. Legislation (U.S. Public Law 100-203) also requires that the foreign shipments of plutonium through U.S. airspace be able to withstand a worst-case aircraft crash, therefore the requirements for packages used for these applications is expected to be even more severe [2]. In accordance with this requirement, the stress analysis of the package at arbitrary impact speed of 200 m/s was performed using the computer model of PAT-2.