Geometric Nonlinearity: Is it Important for Real-time FEM Surgical Simulation?
نویسندگان
چکیده
1. Background/Problem In real-time surgery simulation and planning, the Finite Element Method (FEM) is often used to simulate small and large deformation of human tissue for applications such as laparoscopy training [4], needle insertion planning [1], and image registration [2]. In using FEM, assumptions must be made about material properties and the scale of deformation of human tissues in and around the area of interest. Past work often relies on linear FEM, which assumes that tissues exhibit (1) linear elastic material behavior and (2) geometric linearity. Geometric linearity implies linear FEM is accurate only for relatively small deformations. It assumes material geometry will remain relatively constant both overall and locally and any change in geometry will not affect the distribution of applied forces. While these assumptions may be appropriate for historic applications of linear FEM, such as relatively stiff machine parts, human tissues may be subject to larger deformations making local forces and strains behave in a nonlinear manner. Past work has examined hyperelastic (large deformation) and viscoelastic (rate dependent) properties of structural tissues (tendon, rat tail) done in-vitro with various animals, and some research has examined internal organ tissue [3]. These cases are very specific to the tissue and organ type in question as well as the measurement method, thus these results vary greatly and cannot be assumed for other organs. Little information is available regarding a head-to-head comparison of linear to nonlinear geometry for the soft tissues often modeled in surgery simulation. For a case study of the prostate, we relax one assumption of linear FEM, geometric linearity, and quantify the difference in simulated tissue deformations.
منابع مشابه
Simulation of Surgical Cutting Using a Progressive Cutting Scheme and Extended Finite Element Method
Accuracy and speed are two of the most important problems in the real-time Finite Element Method (FEM)-based simulations of surgical cutting [1][2]. While the latter can be gradually eased through GPU-based acceleration[3][4], the former hasn't been properly addressed even until recently. To enable realistic and accurate simulation, the cutting line should follow the exact movement of the user-...
متن کاملCoupling time-varying modal analysis and FEM for real-time cutting simulation of objects with multi-material sub-domains
متن کامل
Responsive FEM for Aiding Interactive Geometric Modeling
Numerical simulation methods are used mainly as off-line verification tools in current computer-aided engineering systems to reject designs that fail to satisfy the required constraints, rather than to guide the user toward a better design. This paper presents the integration of a real-time finite-element method (FEM) analysis into interactive geometric modeling. Real-time feedback from numeric...
متن کاملPreliminary results on multi-body dynamic simulation of a new test rig for wheel-rail contact
The ability to perform rolling contact fatigue (RCF) experiments in wheel–rail material is provided by a new small–scale test rig, manifesting the actual dynamic behaviour of the railway system. In this paper, a multi-body dynamics (MBD) model is proposed, simulating the vibration behaviour of the prescribed rig. The new testing facility is modelled using a three-dimensional model of the vehicl...
متن کاملQuantitative Comparison of Analytical solution and Finite Element Method for investigation of Near-Infrared Light Propagation in Brain Tissue Model
Introduction: Functional Near-Infrared Spectroscopy (fNIRS) is an imaging method in which light source and detector are installed on the head; consequently, re-emission of light from human skin contains information about cerebral hemodynamic alteration. The spatial probability distribution profile of photons penetrating tissue at a source spot, scattering into the tissue, and being released at ...
متن کامل