Two different delamination mechanisms that
need to be controlled by the drill geometry and thrust force
will be observed in the drilling of composites. The studies
which have been done up to now focus on the thrust force
aspect and drill bit geometry at a constant feed rate.
It is possible to find a feed rate at the beginning of the
penetration that corresponds to the rate at which the
laminates are peeled out. Moreover, at the exit, the fiber
push-down mechanism is active, which can be controlled
by controlling the maximum thrust force. Thrust force itself
depends on the feed rate, so there should be a “feed ratedepth”
graph minimizing the delamination. This implies
that the feed rate may need to be changed from high to low
as the drill bit enters and exits. To find the best result
several experiments are being run at the constant feed rate.
Some of these feed rates will give reduced fiber pull outs at
the entrance and some will result in acceptable fiber push
downs at the exit. The best graph will be extracted by
analyzing the delamination for each feed rate. For
measuring, a microscope should be used to determine the
areas with the maximum delamination along the cross
section of the hole. Also, measuring the surface roughness
is another method of determining the delamination, but it
should be done at a certain depth at the entrance as well as
exit, not all of the thickness at once. 
(Wichita State University. Graduate School., 2007-04-27) Bhargavi, S.S.; Soschinske, Kurt A.; Lankarani, Hamid M.
Space debris, are objects in Earth orbit consisting of small fragments from spent rocket stages and non-functional
satellites. Accumulated in the lower earth orbit, these often cause considerable damage to the spacecraft orbiting around the earth.
Hence it’s necessary to develop ways to protect the newly placed spacecraft from the debris. The goal of the project was to
determine the damage area of the pressure wall using the Smoothed Particle Hydrodynamic (SPH) meshing, a dynamic finite
element modeling (FEM) method.
(Wichita State University. Graduate School., 2007-04-27) Rashidi, Navid; Alavi-Soltani, Seyed R.; Asmatulu, Ramazan
This paper reviews theory and mechanisms of
crevice corrosion as well as its prevention methods. Crevice
corrosion is one of the most important and harmful forms of
localized corrosion that may cause sudden failure of the metal
in service if not prevented properly. So far several protection
methods against crevice corrosion have been developed
including cathodic protection and using inhibitors and
coatings. Hot wax dip method and sealing crevices with
polysulfide are two popular protection methods currently
used in automotive and aerospace industries respectively.
However researches about this devastating type of corrosion