TY - CONF A1 - Eisenacher, Germar A1 - Wille, Frank A1 - Droste, Bernhard A1 - Neumann, Martin T1 - Modeling of wood filled impact limiters for transport packages - 14111 T2 - WM2014 Conference (Proceedings) N2 - Packages for the transport of SNF and HLW are usually equipped with impact limiters to reduce the loads that result from the regulatory 9 m drop test. A common impact limiter design in Germany is a welded steel sheet structure filled with wood. The material wood is the main energy absorber, while the steel sheet provides the integrity of the impact limiter. The IAEA allows mechanical safety cases of transport packages to be carried out computationally, as long as the models used are reliable. In this context, a Finite Element (FE) modeling approach for wood and its application to impact limiters in the calculation of a 9 m drop test is presented. A user material model for wood was developed for the dynamic FE-Code LS-DYNA. Its features are based on a series of crush tests with spruce wood specimens. The model considers wood as a material with transversely isotropic properties, i.e. in the directions parallel and perpendicular to the fiber. The plastic material behavior depends on the state of stress. This has shown to be important to account for the lateral constraint of wood in impact limiters resulting from steel sheet encapsulation. Lateral constraint or respectively, a multiaxial stress state, increases the compression strength level of wood, limits the softening effect and increases the hardening effect. Lateral constraint also increases volumetric and reduces deviatoric deformation. The wood material model considers various hardening and softening characteristics via input flow curves. It considers effects of temperature and strain rate on strength as well. The development of a multi-surface yield criterion and a plastic potential that enables the user input of plastic Poisson's ratios were the challenges during the development of material model. A dynamic FE calculation of a horizontal drop test with an 18,000 kg test package was performed. The wood material model was used to model the wooden impact limiter inlays. The impact limiter deformation and the package deceleration were compared to the experimental drop test results to rate the performance of the wood material model. T2 - WM2014 Conference CY - Phoenix, Arizona, USA DA - 02.03.2014 KW - Transport package KW - Radioactive material KW - Spruce wood KW - Impact limiter KW - Material model KW - Finite element PY - 2014 UR - https://opus4.kobv.de/opus4-bam/frontdoor/index/index/docId/30653 AN - OPUS4-30653 SN - 978-0-9836186-3-8 SP - 1 EP - 10 AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany