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A meshfree method and (the related) a specified crack growth algorithm are used to simulate plugging
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fracture during high-speed impacts. In particular, we are simulating ballistic penetration of a steel plate,
which is a ductile failure process involving projectile and target collision, contact, and subsequent projec-
tile penetration companied plugging fracture inside steel plate. We have developed and implemented an
explicit meshfree Galerkin formulation, which is capable of capturing ductile fractures during finite
inelastic deformation. The developed meshfree computational procedure has the following features:
(1) it has an effective dynamic meshfree contact algorithm that is suitable for high-speed impact; (2)
it can deal with thermal–mechanical couplings, and the stability of coupled thermal–mechanical motion
is guaranteed by an adiabatic split algorithm that integrates adiabatic heating and heat diffusion sepa-
rately; (3) it has an automatic crack growth algorithm that can simulate the whole lifespan of crack
growth including crack nucleation, propagation and arrest; (4) to compute the rate-dependent material
responses, a modified forward Euler tangent algorithm is adopted in constitutive update process for the
nonlinear thermal–mechanical inelastic constitutive relation that takes into account damage evolution.
Results of a numerical simulation of plugging fracture due to projectile/target impact are presented,
and they compare well with experimental data.1. Introduction
Ductile material failures during high-speed impact and penetra-
tion have been a main concern in designing armored vehicles, sea
vessels, and their reliability analysis. Most high-speed impact/con-
tact problems are involved finite deformation and subsequently
material and structural damages induced by high strain rates and
shock waves. To accurately predict such physical process and to
precisely quantify the thermal–mechanical field variables are the
key for novel material and structure designs.
In recent years, there have been some studies on numerical sim-
ulations of high-speed impact and contact problems in the litera-
tures, such as simulations of vehicle crashworthiness, e.g. [5,17,1],
and ballistic impact and penetration, e.g. [12,9–11,35,24]. However,
most of these simulations have remained in the stage of academic
research. To capture the dramatic changes and evolution in struc-
ture geometry and material constitutive relations during high-
speed impacts and to accurately predict ductile failure process have
remained to be challenges of computational failure mechanics.During impact and penetration process, a ductile solid will be
undergoing severe local deformation with extremely high strain
rates and high temperature, which lead to material damage and
fracture. These pose serious challenges for computational study,
for instance, how to simulate crack growth in ductile materials.
Although there are some techniques developed in finite element
methods such as the automatic remesh technology by Wawrzynek
and Ingraffea [30], finite element based methods seem not to be
very successful in ductile fracture simulations. This is because
the ductile fracture is a thermodynamically irreversible process,
which prohibits artificial numerical unloading. On the other hand,
meshfree interpolations have flexibility to adapt computational
domain with evolving topological structure without numerical
unloading. Recently, there have been quite a few research works
using meshfree methods to simulate crack growth, e.g.
[6,7,14,26] among others. In particular, Li and his co-workers have
developed a meshfree crack growth algorithm specifically suitable
for ductile fracture [22,27,28]. In this work, we want to extend the