PRELIMINARY THEORETICAL RESULTS
UPON CONTACT PRESSURE ASSESSMENT BY AID OF REFLECTIVITY
Mechanical Engineering, University of Suceava, ROMANIA
Several different experimental methods for investigating
contact features can be found in literature. The idea to optically
investigate the surfaces of contacting bodies [1-8], led to the
development of a new technique to measure the pressure distributions
in a real contact [9-11].
One of the contacting surfaces is covered, prior to contact
establishment, by a special gel. The contact closing removes the
excess gel and, during a certain time interval, the contact pressure
transforms the entrapped substance in an amorphous solid. In each
point, the refractive index of this solid depends on the pressure
acting during transformation. After contact opening, the
reflectivity of this coating depends on the former contact pressure
and it is mapped by aid of a laser profilometer, thus becoming an
indicator of contact pressure.
This paper studies the effect of pressure on the refractive index of
the solidified gel layer, as well as the different parameters that
influence its reflectivity. Using molecular physics and optics, a
theoretical model of reflectivity is studied and it is found to be
strongly influenced by both pressure and gel layer thickness. From
this model, pressure distribution laws are found for different
ranges of reflectivity and gel layer thickness.
contact pressure, refractive index, reflectivity,
solidified gel layer
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