Page 39 - MY STORY

surface. Charlie was assigned to figure out the

relationship between shot-peening parameters (shot size,
the intensity of the shot, length of time, other stuff) with
the level and depth of compressive stress induced on the

shot-peened surface.

He derived a test specimen that when shot-peened on one

surface would exhibit curvature. The key to making this a
quantitatively useful design tool was to relate the
shot-peened sample radius of curvature to the induced

compressive stress created by shot-peening. My assigned
task was to examine the equations that related sample

curvature to the compressive residual stress on the
shot-peened surface. The derived equation was a
powered-series-solution which was very complex and
required working with a lot of input values derived or

measured from the experiment. It was truly
mind-boggling to me and would require a lifetime of

computations using our “fast” Marchant calculators.

I knew that somewhere in the mathematical series the

terms would gradually fade in significance and could be
dropped from the calculation, but I had no idea of where
that might be. When I explained my problem to Charlie,

he simply looked at me with a typically Chinese calm and