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Static and dynamic finite element analysis of honeycomb sandwich structures
Triplett, Matt H.,Schonberg, William P. Techno-Press 1998 Structural Engineering and Mechanics, An Int'l Jou Vol.6 No.1
The extensive use of honeycomb sandwich structures has led to the need to understand and analyze their low velocity impact response. Commercially available finite element software provides a possible analysis tool for this type of problem, but the validity of their material properties models for honeycomb materials must be investigated. Three different problems that focus on the effect of differences in honeycomb material properties on static and dynamic response are presented and discussed. The first problem considered is a linear elastic static analysis of honeycomb sandwich beams. The second is a nonlinear elastic-plastic analysis of a circular honeycomb sandwich plate. The final problem is a dynamic analysis of circular honeycomb sandwich plates impacted by low velocity projectiles. Results are obtained using the ABAQUS final element code and compared against experimental results. The comparison indicates that currently available material properties models for honeycomb materials can be used to obtain a good approximation of the behavior of honeycomb sandwich structures under static and dynamic loading conditions.
Effects of hydrated lime on radionuclides stabilization of Hanford tank residual waste
Wang, Guohui,Um, Wooyong,Cantrell, Kirk J.,Snyder, Michelle M.V.,Bowden, Mark E.,Triplett, Mark B.,Buck, Edgar C. Elsevier 2017 CHEMOSPHERE - Vol.185 No.-
<P><B>Abstract</B></P> <P>Chemical stabilization of tank residual waste is part of a Hanford Site tank closure strategy to reduce overall risk levels to human health and the environment. In this study, a set of column leaching experiments using tank C-104 residual waste were conducted to evaluate the leachability of uranium (U) and technetium (Tc) where grout and hydrated lime were applied as chemical stabilizing agents. The experiments were designed to simulate future scenarios where meteoric water infiltrates through the vadose zones into the interior of the tank filled with layers of grout or hydrated lime, and then contacts the residual waste. Effluent concentrations of U and Tc were monitored and compared among three different packing columns (waste only, waste + grout, and waste + grout + hydrated lime). Geochemical modeling of the effluent compositions was conducted to determine saturation indices of uranium solid phases that could control the solubility of uranium. The results indicate that addition of hydrated lime strongly stabilized the uranium through transforming uranium to a highly insoluble calcium uranate (CaUO<SUB>4</SUB>) or similar phase, whereas no significant stabilization effect of grout or hydrated lime was observed on Tc leachability. The result implies that hydrated lime could be a great candidate for stabilizing Hanford tank residual wastes where uranium is one of the main concerns.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Hanford tank residual waste could be stabilized by grout. </LI> <LI> Addition of hydrated lime stabilized uranium from leaching through CaUO<SUB>4</SUB>. </LI> <LI> XRD, SEM/EDS and thermodynamic model revealed uranium mineral transformation. </LI> </UL> </P>