A generalized particle algorithm for high velocity impact computations

Abstract

This paper presents a Generalized Particle Algorithm (GPA) for high velocity impact and other dynamics problems. A velocity smoothing algorithm is also presented. This generalized algorithm allows for both variable nodal connectivity and ®xed nodal connectivity. The variable connectivity option allows for severe distortions with a Lagrangian approach. With ®xed nodal connectivity and smoothing it is possible to provide stable computations for large tensile strains. The algorithms are provided for 2D axisymmetric geometry and 3D geometry, and examples are included to demonstrate some of the capabilities. A discussion of interface problems and solutions is also included.

Meshless methods: A review and computer implementation aspects

“…Libersky et al [71] were the first to employ SPH in solid mechanics (impact). Since the original SPH version suffered from spurious instabilities and inconsistencies [97,9,101], many improvements were incorporated into SPH [12,88,20,21,61,62,35,36,100,105]. While SPH and their corrected versions were based on a strong form, other methods were developed in the 1990s, based on a weak form.…”

Simulation of high velocity concrete fragmentation using SPH/MLSPH

“…Belytschko et al [3], Dilts [5], Johnson [8] or Randles et al [9]. For ÿrst-order completeness the following conditions must be fulÿlled:…”

A model for deformation and fragmentation in crushable brittle solids

“…Concrete subjected to explosive loading has been modeled with SPH [45]. The approach followed here is that of Johnson et al [46,47], in which continuum finite elements are converted to meshless particles when specified erosion criteria are met. To this end, the generalized particle algorithm (GPA) of the EPIC 2003 code is used; GPA differs from SPH regarding the choice of smoothing functions [46].…”

“…The approach followed here is that of Johnson et al [46,47], in which continuum finite elements are converted to meshless particles when specified erosion criteria are met. To this end, the generalized particle algorithm (GPA) of the EPIC 2003 code is used; GPA differs from SPH regarding the choice of smoothing functions [46]. This method is computationally efficient and appears natural for modeling fragmentation, as the particle velocities and trajectories can be directly associated with those of the fragments of comminuted material.…”

“…To this end, the authors of [7,62] are commended for providing clear documentation and references used in the determination of material constants of the very same composition of concrete (SAC-7) of interest in the simulations that follow in the present study. Likewise the software developers are acknowledged for supplying an efficient, manageable, and portable code that provided robust algorithms for elementto-particle conversion [46,47] essential for capturing fragment debris in the simulations to be discussed later. Specifically, here the same plastic flow potential in (20), and corresponding plasticity parameters (see later Table 1) are used verbatim from [7].…”