Hi everyone,

I have recently encountered a problem while researching the rate-dependent crystal plasticity constitutive models. I wrote the constitutive model as a UMAT subroutine for calculations in ABAQUS. I need to calculate the polycrystalline deformation for two strain rates, 0.001/s and 3000/s. It is generally believed that high strain rate deformation needs to take into account inertia effects, while low strain rates do not, from this point of view the calculation of high strain rate should be calculated in Dynamic (of course more often in Dynamic explicit), more precisely Dynamic implicit (because I am using UMAT), while low strain rate can be calculated in static. Some papers also use UMAT to calculate deformations with high and low strain rates, but the authors only describe the use of ABAQUS/standard calculations without further explanation of the use of static general or dynamic implicit. I attempted to calculate high strain rate deformation under static general and dynamic implicit conditions; however, the results were not the same and dynamic implicit seems to bring a softening effect compared to static general.

Based on the above, my question is whether the total time in static general has practical physical significance for rate-dependent constitutives？For micron-length RVEs, what issues need to be paid attention to when it comes to the propagation of high-strain rate deformation stress waves？ Should I choose static general or dynamic implicit for the calculation?

Best regards

Siyu Lu