TY - JOUR A1 - Eisenacher, Germar A1 - Scheidemann, Robert A1 - Neumann, Martin A1 - Droste, Bernhard A1 - Völzke, Holger T1 - Dynamic crushing characteristics of spruce wood under large deformations N2 - An extensive series of large deformation crushing tests with spruce wood specimens was conducted. Material orientation, lateral constraint and loading rate were varied. Regarding material orientation, a reduction in the softening effect and the general force level was observed with a higher fiber-load angle. A comparison with characteristics gained by application of Hankinson's formula showed discrepancies in compression strength and the beginning of the hardening effect. Lateral constraint of the specimens caused a multiaxial stress state in the specimens, which was quantified with the applied measuring method. Further, a higher force level compared to specimens without lateral constraint and significant hardening effect at large deformations resulted. Thus, the influence of a multiaxial stress state on the force level could be determined. An increase in the loading rate led to higher force levels at any displacement value and material orientation. KW - Crushing test KW - Dynamic crushing characteristics KW - Spruce wood KW - Lateral constraint KW - Multiaxial stress state KW - Hankinson's formula PY - 2013 U6 - https://doi.org/10.1007/s00226-012-0508-5 SN - 0043-7719 SN - 1432-5225 VL - 47 IS - 2 SP - 369 EP - 380 PB - Springer CY - Berlin AN - OPUS4-27743 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Eisenacher, Germar A1 - Scheidemann, Robert A1 - Neumann, Martin A1 - Wille, Frank A1 - Droste, Bernhard T1 - Crushing characteristics of spruce wood used in impact limiters of type B packages T2 - PATRAM 2013 - 17th International symposium on the packaging and transportation of radioactive materials CY - San Francisco, CA, USA DA - 2013-08-18 KW - Spruce wood KW - Crush test KW - Impact limiter PY - 2013 SP - 1 EP - 10(?) PB - Omnipress AN - OPUS4-30219 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - 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 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 SN - 978-0-9836186-3-8 SP - 1 EP - 10 AN - OPUS4-30653 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -