ARUP; ISBN: 978-0-9562121-5-3 - CMBBE 2012 - Cardiff University

a)
5. DISCUSSION
In this study, we developed a meshless algorithm, in which the analysed continuum was
discretised using a cloud of points/nodes, for modelling of the responses of soft tissue
undergoing elongation and fragmentation. Discontinuities in the deformation field due
to fragmentation are introduced by modifying the nodal domains of influence (using the
visibility criterion) so that nodes located on opposite sides of the crack/notch
(represented in the algorithm by the fragmentation line) do not interact with each other.
Verification of our meshless algorithm against the well-established non-linear finite
element procedures implemented in the ABAQUS code indicates that when modelling
fragmentation and large deformation of a soft tissue-like membrane specimen, the
algorithm yields practically the same results as the ABAQUS code (Fig. 5).
The results of simulation of the experiments on elongation of pia-arachnoid complex by
Jin et al. [13] indicate that our meshless algorithm with visibility criterion for
fragmentation modelling accurately predicts the soft tissue responses in terms of stress–
strain characteristics (Fig. 6) and overall tissue deformation (Fig. 7). However, detailed
quantitative validation of the algorithm’s accuracy in predicting the tissue responses at
very large strains and in the vicinity of rupture-induced discontinuity requires further
investigation.
6. ACKNOWLEDGEMENTS
Fig. 6 Evaluation of performance of our
meshless algorithm with visibility criterion
implemented using the level set function
method. Comparison of the nominal stressstrain
relationship predicted using the
meshless algorithm and the experimental
results on rupture-causing elongation of piaarachnoid-complex
tissue specimens reported
by Jin et al. [15]. Strain rate of 0.05 s -1 .
Fig. 7 Results of application of our meshless algorithm in modelling of the experiments on
elongation of pia-arachnoid-complex tissue specimens by Jin et al. [15]. a) The specimen
deformation for overall sample elongation of 42.5% of the initial length predicted using the
meshless algorithm. Dimensions are in mm; b) Photograph of the deformed tissue specimen.
Financial support of the Australian Research Council (Discovery grants no. DP1092893
and DP20100402) and National Health and Medical Research Council (grant no.
b)