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Title: A finite element model of human skin for surgical simulation
Author: Gasson, Paul David
ISNI:       0000 0004 2672 4701
Awarding Body: University of East Anglia
Current Institution: University of East Anglia
Date of Award: 2008
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In this thesis, a finite element model of human skin is proposed for use in an interactive real-time surgical simulation to teach surgeons procedures such as facial reconstruction using skin flap repair. For this procedure, skin is cut into flaps that are stretched and rotated to cover openings in the face. Thus, the model must recreate the visual and haptic feedback expected by the surgeon. To define the model, a series of experiments were conducted on samples of human skin that were tested in vitro and subjected to uniaxial and planar tensile straining. Hyperelastic materials were then fitted to the stress-strain data produced. Reduced polynomial hyperelastic materials of third to sixth order were found to fit many of the samples' stress responses well. Viscoelastic materials were not considered due to their higher computational complexity and simulation requirements. An explicit dynamic finite element mesh was developed based on the fitted reduced polynomial hyperelastic materials. A total-Lagrangian formulation was used and th.e half-step central difference method was employed to integrate the dynamic equation of motion of the mesh. The mesh was integrated into two versions of a real-time skin simulator: a single-threaded version running on a computer's main central processing unit and a muli-threaded version running on a computer's graphics card. The latter is achieved by exploiting recent advances in programmable graphics technology. The simulator produced stress responses similar to those found by a comercially available finite element analysis package (ABAQUS explicit). Results also matched the skin experiments' data closely (R2 ~ 0.975). The performance of the simulator was also assessed and the multi-processor version proved capable of simulating a mesh of 10000 tetrahedral elements (representing a patch of 44 x 44 x 1 mm sized skin) at 3788 Hz, a rate sufficient for real-time simulation.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available