A comprehensive study on the relationship between yield strength, relative density and ligament sizes is presented for nanoporous Au foams. Depth-sensing nanoindentation tests were performed on nanoporous foams ranging from 20% to 42% relative density with ligament sizes ranging from 10 to 900 nm. The Gibson and Ashby yield strength equation for open-cell macrocellular foams is modified in orde...

Soil liquefaction is a major cause of seismic damage in cohessionless soil during earthquakes. From past numerical and experimental research it has been observed that more excess pore water pressure (EPWP) is generated during earthquakes in a heterogeneous soil deposit than in the corresponding homogeneous soil with relative density equal to the average relative density of the heterogeneous soi...

Spark plasma sintered 3Y-TZP has been investigated with respect to hydrothermal ageing and grinding. The sintering was performed between the temperatures of 1,100 and 1,600 °C for a soaking time of 5 minutes and the resulting materials were obtained with grain sizes between 65 to 800 nm and relative densities between 88.5 to 98.8%. Experiments on hydrothermal ageing in water vapour at 131 °C, 2...

Models are developed in which prey preferences vary between individual predators but the preference of an individual does not change with prey relative density. These two properties generally lead to the surprising conclusion that the aggregate preference of a population of predators does change with prey relative density. This phenomenon may result in negative or positive switching, depending ...

Rigid metallic fiber structures made from a variety of different metals and alloys have been investigated mainly with regard to their functional properties such as heat transfer, pressure drop, or filtration characteristics. With the recent advent of aluminum and magnesium-based fiber structures, the application of such structures in light-weight crash absorbers has become conceivable. The pres...

The mechanical behavior of aluminum hexagonal honeycombs subjected to out-of-plane dynamic indentation and compression loads has been investigated numerically using ANSYS/LS-DYNA in this paper. The finite element (FE) models have been verified by previous experimental results in terms of deformation pattern, stress-strain curve, and energy dissipation. The verified FE models have then been used...

Journal of Composite Materials, Volume 48, May 2014, Pages 1337-1346 http://dx.doi.org/10.1177/0021998313485309 In-plane compression of hollow composite pyramidal lattice sandwich columns Sha Yin, Linzhi Wu, Steven Nutt 1. Center for Composite Materials, Harbin Institute of Technology, Harbin, China 2. Department of Chemical Engineering and Materials Science, University of Southern California, ...

Processing of foams from bulk metallic glass (BMG) alloys, using melt infiltration techniques, is reported for the first time. Foaming methods based on infiltration of two types of pattern materials are described: investment of a continuous refractory yielding very low relative density structures (5% dense relative to the BMG), and investment of a discontinuous refractory pellet bed yielding hi...

Cobalt ferrite is a ferrimagnetic magnetostrictive ceramic that has potential application in magnetoelastic and magnetoelectric transducers. In this work, CoFe(2)O(4) was obtained using a conventional ceramic method and Bi(2)O(3) was used as additive in order to obtain liquid-phase sintered samples. Bi(2)O(3) was added to the ferrite in amounts ranging from 0.25 mol% to 0.45 mol% and samples we...

We are exploring the extended stellar distributions of Galactic satellite galaxies and globular clusters. For seven objects studied thus far, the observed profile departs from a King function at large r, revealing a “break population” of stars. In our sample, the relative density of the “break” correlates to the inferred M/L of these objects. We discuss opposing hypotheses for this trend: (1) H...