A highly adaptive load balancing algorithm for parallel simulations using particle methods, such as molecular dynamics and smoothed particle hydrodynamics (SPH), is developed. Our algorithm is based on the dynamic spatial decomposition of simulated material samples between Voronoi subdomains, where each subdomain with all its particles is handled by a single computational process which is typically run on a single CPU core of a multiprocessor computing cluster.The algorithm displaces the positions of neighbor Voronoi subdomains in accordance with the local load imbalance between the corresponding processes. It results in particle transfers from heavy-loaded processes to less-loaded ones. Iteration of the algorithm puts into alignment the processor loads. Convergence to a well-balanced decomposition from imbalanced one is improved by the usage of multi-body terms in the balancing displacements.The high adaptability of the balancing algorithm to simulation conditions is illustrated by SPH modeling of the dynamic behavior of materials under extreme conditions, which are characterized by large pressure and velocity gradients, as a result of which the spatial distribution of particles varies greatly in time. The higher parallel efficiency of our algorithm in such conditions is demonstrated by comparison with the corresponding static decomposition of the computational domain. Our algorithm shows almost perfect strong scalability in tests using from tens to several thousand processes.

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Ceramic materials have a long-term industrial demand due to their high mechanical hardness and chemical and temperature resistance. They are brittle and tend to lose strength under heavy loads which complicates the development of a comprehensive material model for simulation of engineering prototypes containing ceramic parts. We developed an improved failure model of ceramics based on the well-known Johnson–Holmquist approach. This model redefines the damage rate equation using a consistent definition of the total plastic strain in the failed material. It reduces the number of free model parameters and enables the plastic strain to be explicitly accumulated during the failure process. The corresponding non-iterative algorithm utilizing this explicit failure model is developed. It is successfully validated by simulation of the wave profiles obtained in plate-impact experiments with boron carbide using the contact smoothed particle hydrodynamic method.