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An epoxy penetration technique was used to reproduce and analyze the pitting corrosion process occurred at a steel coupon surface. The samples were exposed to the resin under high vacuum conditions, in order to fulfill the pits caused by the corrosion process. With this technique, a 3D image of the corrosion damages was obtained. Once the image of the damaged surface was obtained, a Scanning Electron Microscope (SEM) was used to analyze the morphology of the pits exhibited by the steel sample. The results were satisfactory, as different parameters such as the diameter, shape and depth of the pits originated, along with the corrosion preferential path, could be established. According to the results, the use of the epoxy penetration technique may be considered as alternating pitting corrosion analysis technique.
Carbon steel cantilever beams are widely used in many applications
in aerospace, civil and mechanical engineering. Pitting corrosion is a
phenomenon which places severe limitations on the design of such applications.
As such, understanding this phenomenon and the methods to deal with it, are of
a great importance. This paper presents numerical investigation by using F. E.
(Finite Element) simulation on the load carrying capacity of corroded
cantilever beams with pitting corrosion damage. The pitting corrosion hole
shape has been modeled using ASTM G46 Standard Guide. Several different cases
of pitting corrosion, represented by hemispherical holes, were modeled and
examined by using ANSYS computer program. Clamped edge constraint was used on
one end, while the other end was free. In these F. E. models, element
of Solid95 was used and comparison to Bernoulli-Euler theory was made. The
effect of the radius of the pitting corrosion holes on the stresses in the beam
was examined in comparison to yield stress. It has been found that the M. S.
(Margin of Safety) has been reduced gradually with increasing radii. Agreement
with Bernoulli-Euler theory has been achieved only for small radii. Moreover,
three methods of pitting corrosion repairs were examined, together with Bernoulli-Euler
theory comparison: 1) Regular surface repair; 2) Extension
surface repair; and 3) “Handy Removal”. It was found that extension surface repair
has the highest M. S. value.