Abstract:
This paper compares the results of finite element analysis (FEA) with physical testing for the DPP-2 shipping package, a Type B fissile material container developed by the Y-12 National Security Complex. FEA was used extensively throughout the design process to evaluate proposed concepts and determine the most damaging orientations for physical prototype testing, as required by regulations. The study focuses on the 9-m drop and 9-m crush tests, which cause the most significant structural deformation, and notes that a cumulative damage approach was used in the FEA to simulate the sequence of drop followed by crush tests. The FEA model, constructed using the TrueGrid preprocessor and the LS-DYNA-3D code, took advantage of a plane of symmetry to model only half of the package. The physical tests were conducted at Oak Ridge National Laboratory's Packaging Research Facility, with six full-size prototypes subjected to a series of tests, including the 1.2-m drop, 9-m drop, 9-m crush, and thermal tests. The paper presents a direct comparison of the deformations predicted by the analytical model and those measured on the actual prototypes for two orientations: the center of gravity (CG)-over-corner and horizontal tests. The results showed good agreement between the FEA predictions and the physical test outcomes, both in terms of quantitative measurements like deformation distances and package diameters, and qualitative visual comparisons of the overall deformed shape. The analysis revealed that FEA accurately simulated the plastic strain and folding of the drum walls, and instances of minor discrepancies were attributed to slight variations in the actual physical tests compared to the precise, intended conditions of the FEA simulations. The paper concludes that FEA is an extremely useful tool for both design development and determining test orientations, with the potential for future use in replacing or significantly reducing the need for physical regulatory testing.
