Subject: Abaqus Mises isotropic plasticity, UHARD user-subroutine calibration.
The material model calibration app in the 3DExperience platform has very good support for the calibration of metal plasticity. Many forms of the plasticity hardening law are supported, including the UHARD user-subroutine. The image above shows test data for a 356 aluminum which we will use in this post to demonstrate the calibration of the UHARD user-subroutine.
Related posts:
Metal Plasticity ; Power-Law Plasticity
Johnson-Cook plasticity The first part of this post will show the calibration of the native Johnson-Cook hardening plasticity model, followed by the calibration of a Johnson-Cook UHARD. In all of the work that follows, the Elastic Modulus (E) = 74754.87 MPa will be held fixed (not a design variable).
The UHARD user-sub was compiled like this:
abq2023hf2 make library=UHARD_JC.f uniquelibs
The above command produces a file named uhard_usub.dll (you must retain this name, do not change it)
Note on units: In numerical mode we are using an Abaqus run to calculate the stress response. In the video below, I chose to work in units of N,mm, MPa. As I enter initial values for the UHARD parameters A, B and n, I am entering them as MPa. Prior to recording the video, I have set my units for Abaqus execution to mm, MPa like this:
The narrated video below was created on Aug 3, 2023 using the R2023 HotFix 3.12 version on the public cloud
When we calibrated the native Johnson-Cook power law, we got this answer:
For the Johnson-Cook UHARD user-subroutine, the parameters are in the same order, but are called generically 'user constant 1', etc. When we calibrated the Johnson-Cook UHARD, we got this answer:
Swift Plasticity The second part of this post demonstrates the calibration of the 'native' Swift hardening law, and a Swift UHARD. The Swift hardening power law is given by this equation:
The UHARD user-sub was compiled like this:
abq2023hf2 make library=UHARD_Swift.f uniquelibs
The above command produces a file named uhard_usub.dll (you must retain this name, do not change it)
The narrated video below was created on Aug 3, 2023 using the R2023 HotFix 3.12 version on the public cloud
When we calibrated the 'native' Swift hardening law we got this response:
When we calibrated the Swift UHARD, we got this response:
The zip file below contains three files: the 3dxml file with the test data, and the two UHARD Fortran source code files.
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