ECCOMAS 2024

Fracture Simulations of Amorphous Materials Using a Concurrent Atomistic-To-Continuum Approach

  • Weber, Felix (FAU Erlangen-Nürnberg)
  • Pfaller, Sebastian (FAU Erlangen-Nürnberg)

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Fracture is a highly complex phenomenon that extends over several length and time scales. Knowledge of the underlying molecular processes is of crucial importance in the development of new and the optimization of existing technical materials with regard to crack resistance. In this context, molecular dynamics (MD) offers the possibility to study the effect of different influencing factors in isolation from each other while preserving the possibility to study the structural rearrangements on an atomistic scale. However, as soon as crack propagation is to be explored under non-affine deformations, such as in the typical Mode I scenario, the classical periodic boundary conditions (PBC) are no longer sufficient. Instead, non-periodic MD systems are needed to capture this type of pseudo-experimental conditions. Moreover, due to the high computational cost of MD simulations, multi-scale approaches combining MD with continuum descriptions are desirable. In view of these challenges, the Capriccio method [1] provides an environment in which appropriate boundary conditions can be applied while reducing the computational cost to the necessary minimum. The Capriccio method is a partitioned-domain approach developed specifically for amorphous materials. Particle regions controlled by MD are coupled with a continuum that is discretized by the finite element (FE) method. The MD and FE regions overlap in a transition zone, the so-called bridging domain, in which the energy contributions of both descriptions are blended. The boundaries of the MD systems to be coupled with the continuum are subjected to non-periodic, so-called stochastic boundary conditions (SBC). Auxiliary particles, referred to as anchor points, are introduced to transfer the forces and displacements between the MD and FE regions. This talk intends to present our recent progress in developing a simulation environment that complements experimental investigations of failure and the derivation of fracture mechanical properties, e.g. crack opening displacement (COD) or energy release rate.