Dinamika Shear Band Saat Gempa Bumi Dengan Memperhitungkan Rolling Resistance Dan Cohesive Force

Abstract

Granular systems represent a complex subject in applied mathematics due to their inherently nonlinear behavior and large-scale inter-particle interactions. This study aims to analyze the effects of rolling resistance (RR) and cohesive force (CF) on micromechanical characteristics, shear band dynamics, and flow regimes based on the inertial number through a numerical modeling approach. Simulations were conducted using a three-dimensional Discrete Element Method (DEM) implementing the Velocity Verlet integration scheme, Hertz-Mindlin contact model, for 1200 spherical particles in a 12×12×12 cm³ domain. Seismic loading was applied with an acceleration amplitude of A = 4.0 m/s² and frequency f = 2.0 Hz (PGA/g = 0.41) across four scenarios namely baseline, RR, CF, and RRCF. Results show that rolling resistance reduced particle rotation by 57.5% and increased the mechanical coordination number to 3.41 up to 3.51 in the combined RRCF scenario, while sharpening shear band localization despite lower mean deformation intensity. Cohesive force produced a more uniform deformation distribution with the lowest localization index (L = 0.7855) and the strongest force chains (𝐹𝑛 max = 12.77 N). The RR and RRCF scenarios yielded the lowest median strain invariant values (≈0.6–0.7 s⁻¹) among all scenarios, and the RRCF scenario in particular showed the lowest peak inertial number (I max = 7.26×10⁻²), indicating the most structurally stable condition within the dense inertial regime shared by all four scenarios. This study demonstrates that DEM-based mathematical modeling is capable of systematically quantifying the influence of contact mechanisms on the collective behavior of systems under dynamic seismic excitation.