Optimization of Johnson-Cook Constitutive Model Parameters Using the Nesterov Gradient-Descent Method

Area of Science:

• Solid Mechanics
• Computational Materials Science
• Numerical Simulation

Background:

• Accurate simulation of deformable solids under impact requires robust material models.
• The Johnson-Cook (JC) model is widely used but requires precise constant calibration, especially at high impact velocities.

Purpose of the Study:

• To develop and validate a method for optimizing JC model constants using Nesterov gradient-descent.
• To enhance the accuracy of numerical simulations for high-velocity impact events.

Main Methods:

• An optimization algorithm based on the Nesterov gradient-descent method was employed.
• A solution quality function was defined to quantify the deviation between simulated and experimental data.
• Numerical simulations of Taylor rod-on-anvil impact tests were conducted for copper specimens.

Main Results:

• The optimized JC model parameters achieved good agreement with experimental and literature data.
• Simulation accuracy (solution quality) improved by 10% across all tested experiments.
• The method demonstrated effectiveness in calibrating material models for high-velocity impact simulations.

Conclusions:

• The proposed optimization method effectively determines optimal JC model constants for improved simulation accuracy.
• This approach enhances the reliability of numerical simulations for impact and shock-wave interactions.
• The methodology is adaptable for other material models and simulation codes in high-velocity impact analysis.