On the Relation between the Percentage of Elongation and Area Contraction in Tension Test

Abstract

There are two or three equations in the past on the relation between the percentage of elongation and area contraction, but we showed, basing on by another idea, certain new equations expressing the relation between the both on the 4th test piece defined in JIS. That is, a General Contraction ψ_g% was considered in addition to a minimum contraction ψ_m%. It is the area contraction of a section that lies at a distance of 3/2 D₀ mm from the minimum sectional area on the longer piece after the test, where D₀ is a diameter before the test. Then we have obtained three equations on the relation between δ and ψ_m, ψ_g, where δ is the percentage of elongation, and it has been found that the calculated values of elongation by these equations coincide well with the measured values. In the three, the following equation is easily applicable to determination of elongation.[numerical formula]