Elastic behavior in contact dynamics of rigid particles

Area of Science:

• Computational physics
• Materials science
• Granular mechanics

Background:

• Contact dynamics (CD) is a common method for simulating granular materials.
• Practical implementation of CD can introduce systematic errors.
• Understanding these errors is crucial for accurate simulations.

Purpose of the Study:

• To investigate systematic errors in the practical implementation of the contact dynamics method.
• To analyze the emergence of effective elasticity and finite sound propagation in simulations.
• To determine the applicability limits of the CD method and compare it with soft particle molecular dynamics (SPMD).

Main Methods:

• Analytical investigation of simulation artifacts.
• Numerical simulations of rigid particle chains using iterative solvers.
• Comparison with soft particle molecular dynamics simulations.

Main Results:

• The use of standard iterative solvers in CD simulations of rigid particles leads to apparent effective elasticity.
• Finite sound propagation velocity is observed in these simulations.
• The characteristics of these phenomena were quantified.

Conclusions:

• The study identifies and quantifies systematic errors in CD simulations.
• Effective elasticity and finite sound speed are artifacts of the iterative solver implementation.
• The findings provide a basis for assessing the applicability of CD for granular media simulations.