An inverse analysis to identify the Johnson-Cook constitutive model parameters for cold wire drawing process

Ashkan Mahmoud Aghdami,Behnam Davoodi

doi:10.1051/meca/2020070

Ashkan Mahmoud Aghdami, Behnam Davoodi

Open Access

https://doi.org/10.1051/meca/2020070

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Abstract

Johnson-Cook constitutive equation was utilized to model the 10100 copper and AA 1100 aluminum wires at the cold wire drawing process. Initial Johnson cook parameters were determined through quasi-static tensile tests at different strain rates. Analytical and finite element with VUHARD subroutine solutions were implemented to calculate the drawing forces using the Johnson cook parameters. Wire drawing experiments were carried out at different drawing conditions with two areal reductions and four drawing speeds with the strain rate ranged from 37 s−1 to 115 s−1 and wire drawing forces were measured using a load cell connected to the drawing die. Results showed that the Johnson cook model with parameters determined from a quasi-static condition was not able to predict the material behavior at the wire drawing process with a moderate strain rate. In order to modify the initial JC parameters an inverse analysis approach was adopted. An objective function was defined based on analytical and experimental drawing forces differences with respect to JC parameters. Using the Newton–Raphson method, new JC parameters were identified by minimizing the objective function. Updated Johnson cook parameters showed much more correlation with experimental results.

Highlights

The wire drawing process consists of reducing the crosssection of wires by forcing them through a series of dies
Among the empirical or phenomenological based models, Johnson–Cook equation [7] is one of the primary constitutive models used widely for metals subjected to a large strain, high strain rate, and high temperature
The number of error in lower drawing speeds is smaller compare to higher drawing speeds because in lower drawing speeds, the strain rate in wire drawing is close to quasi-static strain rate condition in which the JC parameters where determined

Summary

Introduction

The wire drawing process consists of reducing the crosssection of wires by forcing them through a series of dies. Most of the studies on the wire drawing process were focused on finding optimum process parameters using finite element methods or by experimental approach [1,2,3,4]. He et al [5] studied the strain rate effect on the flow stress of carbon steel wires without mentioning the material model used. Among the empirical or phenomenological based models, Johnson–Cook equation [7] is one of the primary constitutive models used widely for metals subjected to a large strain, high strain rate, and high temperature. Chen [9] noted the coupling effect of the work hardening and strain rate for 7050-T7451 alloy and coupled effect of thermal

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