The
center has two research-grade skidless contact profilometers: one is a
standard tabletop model (shown to the right) and the second is the
portable model shown below attached to our custom three-axis
positioner. A profilometer uses a diamond tip dragged across a surface
to generate a trace that is representative of the actual surface shown
below. The typical tip radius is 5 micrometers. As the tip moves
across the surface, an electrical signal is received that gives the
relative height of the surface to an ultimate resolution (zero noise
limit) of 7 nanometers. The tabletop model has a maximum trace length
of 60 mm and may be used in conjunction with a motorized x-y table.
The three-axis positioner has a 13-nanometer resolution for movements
along the x-axis and a 19-nanometer resolution for movements along the
y- or z-axes. The positioner allows the portable profilometer to be
used to measure surfaces as they are generated on our subscale aircraft
dynamometer. The absolute wear of a topographical area is measured to
monitor the evolution of the two brake rings with brake testing.