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

2-D MESHLESS ALGORITHM FOR MODELLING OF SOFT TISSUE
UNDERGOING FRAGMENTATION AND LARGE DEFORMATION:
VERIFICATION AND PERFORMANCE EVALUATION
Xia Jin 1 , Guiyong Zhang 1 , Grand. R. Joldes 1 , King. H. Yang 2 , Xin Jin 2 ,
Pierre-Y. Rohan 3 , Karol Miller 1 , Adam Wittek 1
1. ABSTRACT
In injury biomechanics and surgery simulation, modelling of soft tissues/soft organs is
generally performed using (non-linear) finite element procedures. However, the
accuracy of finite element method deteriorates when the mesh undergoes fragmentation
and distortion due to damage/cutting and large deformations caused by injury and
surgical intervention. Therefore, in this study, we developed a meshless algorithm with
visibility criterion for fragmentation modeling. The algorithm provides robust solution
for predicting soft tissue responses for large strains and discontinuities due to
fragmentation.
Verification against the well-established non-linear finite element procedures available
in ABAQUS confirms the accuracy of our meshless algorithm with visibility criterion
for fragmentation modelling. Evaluation of the algorithm performance through
modelling of the pia-arachnoid tissue samples subjected to rupture-causing elongation
indicates that the overall deformation within the sample predicted by the algorithm
qualitatively agrees with that observed in the previously published experimental results.
2. INTRODUCTION
The ability to model fragmentation of soft tissues due to rupture/cutting is of immense
importance for impact and injury biomechanics as well as for biomechanics for
medicine. Potential applications include computer evaluation of car crash safety
performance through modelling of traumatic injury to car occupants and pedestrians as
well as simulators for surgical training and surgery planning.
So far, in both impact/injury biomechanics and surgery simulation, non-linear finite
element procedures have been a method of choice [1-6]. However, the finite element
method becomes unstable and its accuracy deteriorates when the finite element
computational grid (i.e. finite element mesh) undergoes fragmentation and distortion
due to rupture/damage of the analysed continuum [7].
1 Intelligent Systems for Medicine Laboratory, School of Mechanical and Chemical Engineering, The
University of Western Australia, 35 Stirling Highway, Crawley-Perth 6009, Western Australia, Australia
2 Bioengineering Center, Wayne State University, 818 W. Hancock, Detroit, MI 48201, USA
3 Ecoles des Mines de Saint-Etienne, France (study conducted during internship at Intelligent Systems for
Medicine Laboratory, The University of Western Australia)