Van Vlack claims that there is no mathematical relationship between the two measures of ductility viz elongation and reduction
of area. In this paper, we prove that there is a relationship between the two measures that involves the golden mean parabola. Even
is a subject as old as Mechanics, we can still make discoveries.
Keywords: Ductility; Stress; Strain; Golden Mean parabola; AT Math
Ductility is a measure of a metal’s ability to withstand tensile
stress, which is a force pulling the two ends of an object
away from each other. Ductility is a measure of a metal’s ability
to withstand tensile stress, which is a force pulling the
two ends of an object away from each other (Source; Wikipedia).
There are two methods to measure ductility. One is
elongation (strain); the second is reduction of area .
Van Vlack states that there is no mathematical relationship
between the two measures of ductility. In this paper, we will
unite the two mathematically. Assume a specimen that is circular
in cross-section.