Optimization of Energy Absorbing Materials for Radioactive Packaging
Most applications of honeycomb materials are for lightweight structural members. This area of honeycomb material behavior has been extensively researched. In packaging design, honeycomb materials are used for impact energy absorption. Data concerning the deformation of stainless steel honeycomb structures is not widely available. It is being proposed to use honeycomb stainless steel as an impact energy absorber in a new radioactive material shipping package. Honeycomb materials can be useful for energy absorption applications because the geometry causes the structure to have a constant compressive force during buckling. This Finite Element Analysis is used to predict the compressive buckling strength of various honeycomb structures in order to design an energy absorber for a specific package weight and geometry. The model simulates a drop test where a 50 pound plate lands flat on a honeycomb stainless steel structure from a height of 30 feet. Some actual drop tests have already been performed on real specimens. Most of the resulting deformations of these tests include the bottom of the honeycomb structure buckling while the rest of the structure was either slightly deformed or straight. The deformation of the simulated honeycomb specimen matched the deformation from the actual drop tests. This is one verification that the model is working properly. It is evident that after about 2.5% strain the strength is a relatively linear value, and eventually flattens out to about 875 psi. The crush strength measured from the actual drop tests for the same density honeycomb was just over 800 psi. This is further verification that the model is working correctly. The results gathered from the FEA model successfully mirror the results from a real drop test. The deformation looks realistic, and the compressive strength found is consistent with the empirically measured value. Future work for this model includes modeling different density honeycomb structures which have not been tested before. This will allow for optimization of honeycomb stainless steel use for impact absorption in radioactive material shipping packages.