Comparison Dogbone and Rectangular Specimen for Tensile Test Mechanical Properties Using Steel Plate Cold Rolled Commercial (SPCC)

Abstract

Tensile testing is a fundamental method for evaluating the mechanical properties of materials under uniaxial tension. The standard tensile test specimen, also often referred to as the dogbone specimen due to its shape with a narrowed gauge section and enlarged ends, is designed to produce uniform stress distribution and ensure deformation and fracture occur within the gauge section. This configuration is preferred in standards such as ASTM E8/E8M for determining tensile strength, yield strength, and modulus of elasticity, which are considered true representations of a material’s intrinsic properties. An alternative geometry, the rectangular specimen, features a uniform cross-section and is occasionally used for practical purposes, particularly in educational or resource-limited settings. While easier to prepare, the rectangular shape does not control stress distribution as effectively as the dogbone, and this can lead to premature failure near the grips or overestimation of strength. This study compares the tensile behavior of dogbone and rectangular specimens made from Cold Rolled Commercial (SPCC) steel plates of varying thicknesses. Testing is conducted using a Universal Tensile Testing Machine (UTM), and the results are analyzed to evaluate how closely the rectangular specimen approximates the mechanical properties obtained from the standard geometry. The objective is not to challenge the standard, but to explore whether rectangular specimens can offer sufficiently reliable data for non-critical applications. This study highlights the trade-offs between geometric precision and preparation efficiency, acknowledging the limitations introduced by simplified specimen designs.

Keywords: Tensile Test, Dogbone, Rectangular