A strain rate dependent thermo-elasto-plastic constitutive model for crystalline metallic materials

Area of Science:

• Materials Science
• Mechanical Engineering
• Computational Mechanics

Background:

• The influence of strain rate and temperature on crystalline metal deformation is a critical area of research.
• Understanding these effects is essential for predicting material performance in diverse applications.

Purpose of the Study:

• To develop a strain rate-dependent thermo-elasto-plastic constitutive model for crystalline metals.
• To investigate the deformation behavior of metals across a wide range of strain rates and temperatures.

Main Methods:

• Decomposition of the deformation gradient into thermal, elastic, and plastic components.
• Introduction of thermal strain into the total strain to establish a thermo-elastic constitutive equation.
• Proposal of a novel stress-plastic strain relationship to capture strain rate and temperature effects on flow stress and work-hardening.

Main Results:

• Calculated stress-strain curves for face-centered cubic (copper), body-centered cubic (Tantalum), and two-phase (Ti-6Al-4V) metals.
• Model validation against experimental data across strain rates from 10⁻⁶ to 6000 s⁻¹ and temperatures from 233 K to 730 K.
• Demonstrated good agreement between model predictions and experimental results.

Conclusions:

• The developed constitutive model effectively describes the deformation behavior of crystalline metals.
• The model is concise and suitable for practical engineering applications.
• This work provides a valuable tool for predicting metal behavior under complex loading conditions.