Open Access. Powered by Scholars. Published by Universities.®
- Keyword
Articles 1 - 4 of 4
Full-Text Articles in Engineering
A Study Of The Diffusion Characteristics Of Tungsten Bar Stock And Tungsten Produced Via Direct Metal Laser Sintering (Dmls), Jonathan Robert Bruss
A Study Of The Diffusion Characteristics Of Tungsten Bar Stock And Tungsten Produced Via Direct Metal Laser Sintering (Dmls), Jonathan Robert Bruss
Master's Theses (2009 -)
Using a vacuum hot extraction method diffusivity and concentration of hydrogen were measured in samples of tungsten bar stock and direct metal laser sintered (DMLS) tungsten. It was found that the tungsten bar stock closely adhered to the model established by Frauenfelder. The DMLS samples approximately follow a downward sloping trend over the 500K-1200K temperature range. The trend is opposite of what is expected suggesting processing has a major effect on diffusion behavior. A CFD model was created using ANSYS Fluent to simulate the diffusion behavior. The model functions by separating out diffusion mechanisms and solving Fick’s law with each …
Dynamic Behavior Of Granular Earth Materials Subjected To Pressure-Shear Loading, Jeff Wilson Lajeunesse
Dynamic Behavior Of Granular Earth Materials Subjected To Pressure-Shear Loading, Jeff Wilson Lajeunesse
Dissertations (1934 -)
The dynamic response of granular earth materials such as sand has been of interest for many years. Multiple previous works have explored the shock response of sand in various grain shapes, sizes, and moisture contents, but the response during rapid combined loading has been relatively unexplored. The current study contributes to that lack of data by performing pressure-shear experiments on Oklahoma #1 silica sand, with quasi-smooth grains of 63 - 120 micron diameter and 99.8 wt.% Si02 composition. In these experiments, an oblique flyer plate impacts an equally inclined target, imparting a longitudinal (pressure) and transverse (shear) wave into a …
Ramifications Of Projectile Velocity On The Ballistic Dart Penetration Of Sand, Peter Anthony Sable
Ramifications Of Projectile Velocity On The Ballistic Dart Penetration Of Sand, Peter Anthony Sable
Master's Theses (2009 -)
With the advent of novel in-situ experimental measurement techniques, highly resolved quantitative observations of dynamic events within granular media can now be made. In particular, high speed imagery and digital analysis now allow for the ballistic behaviors of sand to be examined not only across a range of event velocities but across multiple length scales. In an attempt to further understand the dynamic behavior of granular media, these new experimental developments were implemented utilizing high speed photography coupled with piezo-electric stress gauges to observe visually accessible ballistic events of a dart penetrating Ottawa sand. Projectile velocities ranged from 100 to …
Implications Of Heterogeneity In The Shock Wave Propagation Of Dynamically Shocked Materials, Jeffrey W. Lajeunesse
Implications Of Heterogeneity In The Shock Wave Propagation Of Dynamically Shocked Materials, Jeffrey W. Lajeunesse
Master's Theses (2009 -)
The field of shock physics as a whole has only recently begun to pay particular attention to modeling heterogeneous materials under shock loading. These materials are important because of their practicality in terms of creating stronger, more shock resistant materials. To understand why they absorb shock impact energy better than homogeneous materials means that the small-scale processes that occur during the shock loading of these heterogeneous materials needs to be understood. Recent computational experiments, called mesoscale simulations, have shown that explicitly incorporating small-scale heterogeneous features into hydrocode simulations allows the bulk shock response of the heterogeneous material to be observed …