Crushing Characteristic of Rigid Polyurethane Foam as Shock Absorbing Material for Transport Cask

In this study, crushing characteristics of rigid polyurethane form (R-PUF) were obtained, and applicability of R-PUF as shock absorbing material for transport cask was verified. Firstly, the stress-strain curves of R-PUF under constant strain-rate conditions were obtained using constant deformation rate testing machine by varying R-PUF density between 0.1 to 0.8 g/cm3, strain-rate between 1.25×10-3 to 1.25×101/s, and temperature between 20 to 80 °C. Then, the material crushing data collection to apply design and numerical analysis was accumulated. Secondly, side and 10°-declined 9m drop tests of 1/3 scale model cask that had impact limiter designed using material data obtained in this study were conducted. As the result showed the shock-absorbing performance obtained in the test was superior to as designed, applicability of designing R-PUF impact limiters based on the material data collection in this study was verified. Moreover, the 9m drop tests were numerically simulated in LS-DYNA using material data considering the strain rate dependency obtained in this study. As impact acceleration was estimated effectually in the numerical simulations, the validity of the strain rate dependency in the material data was confirmed. Finally, drop weight tests were conducted by varying R-PUF density between 0.1 to 0.65 g/cm3 and temperature between -20 to 80 °C to valid applicability of extrapolation of the dependencies of temperature in the material data collection.