Development and validation of a finite element model for lumbar motion segment (L_4-L_5)
- VernacularTitle:腰椎L_4~L_5活动节段有限元模型的建立与验证
- Author:
Yaosheng LIU
- Publication Type:Journal Article
- Keywords:
biomechanics;
finite element method;
computer aided design;
lumbar spine;
surface model;
validation
- From:
Academic Journal of Second Military Medical University
1985;0(06):-
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To develop and validate an accurate three-dimensional geometrical and mechanical finite element(FE)model of the lumbar L_(4)-L_(5) segment using a new computer-aided designing(CAD) method.Methods: First,a modified "non-seed region segmentation" was done to extract the interest region in the CT image and to obtain a binary image,from which the iso-surface of vertebral body was produced by a discretized marching cubes algorithm.Second,"best cross-section planes" representing the morphologic characteristics of physiological lordosis were used for the initial iso-surface model,forming a "non-regular piecewise subspace".This subspace and the embedded iso-surface model were subsequently transformed by local affine transforms to a "regular subspace",in which a surface mesh of high quality was generated quickly.Finally,a reverse transform procedure was employed to restore the original three-dimensional(3D) image of the lumbar surface mesh of lumbar L_(4)-L_(5).All coordinate dada of nodal points and message of triangular patches of the surface model were then subjected to ANSYS for the three-dimensional FE mesh construction.An accurate 3D non-linear FE model of lumbar motion segment(L_(4)-L_(5)) was developed and validated against published data.Results: The constructed FE model of lumbar L_(4)-L_(5) consisted of 94 794 solid elements,1 196 link elements,1 170 shell elements,768 target elements and 464 contact elements,and included geometrical,material and contact non-linearities.The predicted results of lumbar L_(4)-L_(5) segment were closely correlated with published results of experimental biomechanics in terms of axial displacement,segment rotation and intradiscal pressure under similar load condition.Conclusion: Based on advanced algorithm,this constructed surface model of L_(4)-L_(5) segment is capable to perform whole digitalized binary image extraction and reconstruction of the lumbar surface with excellent simulation results.
