Conversion from relaxation modulus to dynamic modulus

J-OCTA includes several methods for calculating viscoelastic master curves from relaxation modulus data obtained in simulations. Here, i-Rheo GT was used to calculate G′ and G″ from Molecular Dynamics results, applying the time–temperature superposition principle to obtain properties over a wide frequency range. As verification, it was applied to viscoelastic solids and results from Coarse-Grained MD of polymers, showing good agreement with theoretical values. i-Rheo GT can be operated easily from the GUI, making it an effective tool for understanding and designing the viscoelastic properties of polymer materials.

Use Cases Highlights

Conversion of relaxation modulus to dynamic modulus
Applicable to analysis of various materials
Also useful for analysis of experimental results

Conversion of relaxation modulus to dynamic modulus

Results of applying the i-Rheo GT method to a viscoelastic solid are shown. While FFT shows errors at low frequencies, i-Rheo GT agrees well with theoretical solutions.

Application to viscoelastic solids

Applicable to the analysis of various materials

The results of evaluating a viscoelastic master curve using the relaxation modulus G(t) obtained from Coarse-Grained Molecular Dynamics (CGMD) with the Kremer–Grest model are shown. The results from FFT and i-Rheo GT are in good agreement, confirming the effectiveness of the method.

Evaluation of viscoelastic master curve using relaxation modulus obtained from Coarse-Grained Molecular Dynamics (CGMD)

Useful for analysis of experimental results as well

An overview of the linkage between i-Rheo GT and J-OCTA is shown. By passing simulation results from J-OCTA to i-Rheo GT, viscoelastic properties can be quickly evaluated, and the linkage flow is visually explained.

Overview diagram of linkage between i-Rheo GT and J-OCTA

Reference

[1] M. Tassieri, et al., Macromolecules 51, 14, 5055-5068 (2018)
[2] M. Tassieri, et al., Journal of Rheology 60, 649 (2016) (2016's most read article in the Journal of Rheology)

Details of analysis