応用機械工学ジャーナル

概要

New Approach of Metals Ductility in Tensile Test

Badreddine R, Abderrazak D and Kheireddine S

Abstract

Ductility is the ability of a material to deform plastically before rupture. This is an important feature in shaping because it helps to define the behavior of materials. Ductility is therefore essential to know and thus determine to anticipate the behavior of materials in various situations of stress. Ductility is commonly defined by the two parameters A elongation (in percent) or necking Z (in percent) with:

A(%) = ΔL/L_0(%) = (L_1-L_0)/L_0(%) and Z(%) = ΔS/S_0(%) = (S_0-S_1)/S_0(%)

These two parameters are determined from tensile tests on standard specimens.

We will focus on the study and analysis of ductility using the tensile test.

However these two indicators (A) and (Z) of the ductility may present deficiencies (contradictions) in the interpretation of the ductility in case where for two samples (1) and (2) with same original dimensions (Lo) and (So) and different composition we could have : A1>A2 and Z1 Z2.

These two cases show the anomaly between A and Z in the assessment of the ductility, in fact in the first case the sample (1) is more ductile than the sample (2) in terms of elongation (A) is less ductile necking in terms of (Z) against the 2nd case we find the opposite behavior; it is this inconsistency that we will approach the ductility by introducing a parameter which will be called ductility (D) which takes into account the elongation and necking in a single formulation. In fact, (D) could remedy this deficiency involving computational approaches by activating the settings of the length (L) and Section (S) across the diameter (d) together in a first approach and to other computational approaches that take into account the elongation A and the neck.