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• Cutting in real-time in corrotational elasticity and perspectives on simulating cuts

Web page

http://www.engin.cf.ac.uk/whoswho/profile.asp?RecordNo=679

Categories

Biomechanics, Boundary elements, Complex Systems, Computer Science, Distributed computing, Elasticity, Finite elements, Level set, Materials, Medical Imaging, Meshless methods, Multi-core, Multi-physics, Multi-scale, Multigrid solvers, Optimisation, ParaView, Quantitative Biology, Simpleware, Software Engineering, Structural biology, Structural dynamics, Tribology, Visualisation, Voxel imaging, VTK

Submitter

Georges Limbert

ABSTRACT We focus here on the simulation of surgical acts of types similar to cutting and needle insertion in soft tissue, in real time (500Hz), where the scale of the surgical instrument is several orders of magnitude smaller than that of the organ. We provide review of the state of the art and make propositions to address some of the main difficulties in this area:

• complex geometries -implicit boundaries, XFEM, meshless, advanced meshing
• multiple scales (large gradients) -domain decomposition and model reduction [4]
• error control and adaptivity [1]
• parallel implementation Graphical Processing Units (GPUs) [2, 3]

We then describe a series of contributions in the field of real-time simulation of soft tissue biomechanics. These contributions address various requirements for interactive simulation of complex surgical procedures. In particular, we present results in the areas of soft tissue deformation, contact modelling, simulation of cutting, and haptic rendering, which are all relevant to a variety of medical interventions. The contributions we describe share a common underlying model of deformation and rely on GPU implementations to significantly reduce computational expense.

Preliminary results The ERC RealTcut starting grant started in January 2012. Since then, we have made a number of advances, in particular in the area of real time simulation of cutting. Since the second quarter of 2012, Dr. Hadrien Courtecuisse (Ph.D. from the SHACRA team with Stéphane Cotin, Jérémie Allard and Christian Duriez), who was the first to undertake implicit cutting on multicontacting deforming solids GP-GPUs simulations [3] joined RealTcut. We have shown that it is possible to cut non-linear solids formulated within a corrotational formalism in real time with a tetrahedron subdivision method and a Sherman-Morrison update. The next steps include assessing the error associated with the single Newton iteration, extending to non-linear materials, and investigating the improvements enabled by enriched approximations. These results will form the base of the real-time work.

References

[1] Wu X., Downes M.S., Goktekin T., and Tendick F. Adaptive nonlinear finite elements for deformable body simulation using dynamic progressive meshes. Computer Graphics Forum, 20(3), (2001).

[2] Joldes G.R., Wittek A., Miller K. Real-time nonlinear finite element computations on GPU-application to neurosurgical simulation Computer Methods in Applied Mechanics in Engineering in press. (2010)

[3] Courtecuisse H., Junga H., Allard J., Duriez C., Lee D.Y., Cotin S. GPU-based real-time soft tissue deformation with cutting and haptic feedback Progress in Biophysics and Molecular Biology (2010)

[4] Kerfriden P, Passieux J C, Bordas S, Local/Global model order reduction strategy for the simulation of localised failure, International Journal for Numerical Methods in Engineering , 89 (2) (2012) 154-179

BIOGRAPHY Stéphane P. A. Bordas (SB) has been professor of computational mechanics since 2009 at Cardiff University, ERC Starting Grant Holder since 2012 and is the director of the institute of Mechanics and Advanced Materials (iMAM). His research group is composed of about 20 researchers in modelling and simulation for mechanics, materials and systems for problems involving discontinuities and singularities. This team has made contributions to the extended nite element method (XFEM), isogeometric analysis (IGA) and extended meshfree methods (XMM) with applications to dura- bility of complex structures. In collaboration with Prof. Timon Rabczuk (Weimar),they have released 5 open source codes available here for XFEM, (X)IGA, IGA-BEM, and XMM and an advanced multi-scale fracture code coupled to LAMMPS and known as PERMIX. He is leading in Cardiff, also in collaboration with Prof. Rabczuk an FP7 ITN on Computer-Aided Design-Analysis transition (INSIST). The group published about 50 international journal papers which can be consulted here (http://scholar.google.co.uk/citations?user=QKZBZ48AAAAJ&hl=en). The mission of the 15 members of academic staff forming the institute of Mechanics & Advanced Materials (iMAM), led by Stéphane is to develop, validate and verify reliable models and robust, accurate and efficient high-performance simulation tools to describe and understand advanced materials and structures, over a wide range of spatial and temporal scales. The group holds a blog (http://stephanebordas.blogger.com/)and an online discussion forum in computational mechanics (http://groups.google.com/group/computational_mechanics_discussion/about) and is keen to help newcomers to the discipline get started by sharing research ideas and codes.