Understanding Deformation Behavior in Uniaxial Tensile Tests of Steel Specimens at Varying Strain Rates

Published

February 22, 2022

Author(s)

Dilip K. Banerjee, Mark Iadicola, Adam Abel Creuziger

Abstract

Uniaxial tensile tests are routinely conducted to obtain stress-strain data for forming applications. It is important to understand the deformation behavior of test specimens at plastic strains, temperatures, and strain rates typically encountered in metal forming processes. In this study, the Johnson-Cook (J-C) flow stress model was used to describe the constitutive behavior of ASTM International (ASTM) A 1008 steel specimens during uniaxial tensile tests at three different average strain rates (10−5 s −1 , 10−3 s −1 , and 10−1 s −1 ). The digital image correlation (DIC) technique was used for displacement and strain measurement, and two-dimensional (2D) infrared (IR) imaging was employed for temperature measurement. Separate optimization studies involving relevant finite element (FE) modeling with appropriate measured data yielded optimum values of convective heat transfer coefficients, J-C parameters, and inelastic heat fraction variables. FE modeling employing these optimum parameter values was then used to study the mechanical behavior. While FE predictions matched measured strain localization and thermal field very well in the intermediate- and low-rate experiments, the high-rate test showed narrower strain localization and a sharper temperature peak in the experiment. Possible use of a higher steel thermal conductivity value and/or exclusion of material inhomogeneities may have resulted in discrepancies between computed and measured temperature and strain fields. The study shows that an optimized set of parameters obtained with a controlled test could be reasonably applied for other tests conducted at very different strain rates.

Citation

Journal of Research (NIST JRES) -

Volume

126

NIST Pub Series

Journal of Research (NIST JRES)

Pub Type

NIST Pubs

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DOI Link

Keywords

deformation, finite element analysis, Johnson-Cook model, localization, optimization, strain, strain rate, temperature, tensile test

Citation

Banerjee, D. , Iadicola, M. and Creuziger, A. (2022), Understanding Deformation Behavior in Uniaxial Tensile Tests of Steel Specimens at Varying Strain Rates, Journal of Research (NIST JRES), National Institute of Standards and Technology, Gaithersburg, MD, [online], https://doi.org/10.6028/jres.126.050 (Accessed December 12, 2024)