Transcript final poster.2

Background:
Warhead design engineers and material scientists require mechanical property
information under high deformation rates of loading on a wide variety of materials that
have military significance. Over the past decade, a new class of materials has begun to
receive attention because it affects the performance of most all warhead designs. This
new class is called “particulate materials” and includes a diverse collection of materials
such as sand, explosive grains and potting materials. One technique used to probe the
behavior of such materials is to fill a large “box” with sand and fire a hemisphericalnosed projectile into it. During such events, the projectile disturbs and crushes the
sand. It has been noted that the disturbed/crushed state of the sand correlates with the
conditions that affected it.
Target:
Projectile:
Fractured Sand:
High Speed Impact Sand and
Target Sampling Apparatus
Eglin AFRL Test Results :
Position vs. Time
Velocity/Acceleration vs. time
Need:
There is no good technique for extracting sand
samples making so many measurements not very
definitive or useful. The Damage Mechanisms Branch
has a requirement to develop a new technique for
extracting sand samples from the target.
The figure to the right shows the target used for
sampling. Nearly all of the sand has been excavated to
reveal the projectile shot line.
Once revealed,
researchers take samples along the length of the
target. The images below show the partial fractures of
the sand particles under a SEI microscope.
Florida A&M University
Florida State University
Materials and Methods:
a.) Chain and Actuators
b.) Vacuum
A mechanism was idealized and conceived from the ground up to include a functional
system that would not only remove sand quickly, but more accurately than previous
methods. The system, as seen above, consists of a chain and sprocket pulley design.
Corrosion resistant steel roller chain(#35, Single Strand, 3/8" Pitch, .200" Dia.) draws
the apparatus along the length of the target. A frame has been fashioned to fit securely
into the target. Removal of sand is done by a dual ended vacuum as seen in figure b.
This design extracts sand from one end, bypasses the motor and ejects the material
into any container.
Results:
While the original goal was for the system to be fully automated, time constraints
allowed for toggle switch automation of the system. With the inclusion of an
aluminum frame, the mechanisms movement is smooth and effective.
Ruben DeSousa, Richard Klimas, Daniel Mortensen, Gina Teofilak
Sponsor: Dr. William Cooper, Eglin Air Force Research Laboratory
Advisor: Dr. Ongi Englander
Special Thanks: Dynatech Associates, Dr. Jonathan Clark, Dr. Carl Moore
For More Information Visit: http://www.eng.fsu.edu/ME_senior_design/2009/team4/