USE OF THE FINITE ELEMENTS METHOD FOR THE IMPLEMENTATION OF THE COPLANAR CAPACITIVE SENSOR MODEL

AbstractThe finite elements method allied with the computerized axial tomography (CT) is a mathematical modeling technique that allows constructing computational models for bone specimens from CT data. The objective of this work was to compare the experimental biomechanical behavior by three-point bending tests of porcine femur specimens with different types of computational models generated through the finite elements’ method and a multiple density materials assignation scheme. Using five femur specimens, 25 scenarios were created with differing quantities of materials. This latter was applied to computational models and in bone specimens subjected to failure. Among the three main highlights found, first, the results evidenced high precision in predicting experimental reaction force versus displacement in the models with larger number of assigned materials, with maximal results being an R2 of 0.99 and a minimum root-mean-square error of 3.29%. Secondly, measured and computed elastic stiffness values follow same trend with regard to specimen mass, and the latter underestimates stiffness values a 6% in average. Third and final highlight, this model can precisely and non-invasively assess bone tissue mechanical resistance based on subject-specific CT data, particularly if specimen deformation values at fracture are considered as part of the assessment procedure.

The article presents modeling of human lumbar vertebra and it‘sdeformation analysis using finite elements method. The problemof tissue degradation is raised. Using the computer aided modelingwith SolidWorks software the models of lumbar vertebra(L1) and vertebra system L1-L4 were created. The article containssocial and medical problem analysis, description of modelingmethods and the results of deformation test for one vertebramodel and for model of 4 vertebras (L1-L4). Santrauka Straipsnyje aprašomas stuburo juosmeninės dalies slankstelio (L1) bei juosmeninės dalies slankstelių (L1-L4) sistemos modeliavimas ir tyrimas baigtinių elementų metodu (BEM). Sukuriamas erdvinis skaitinis modelis programinės įrangos SolidWorks aplinkoje. Sudaroma vieno ir keturių slankstelių (L1-L4) skaičiuojamosios schemos, modeliams suteikiama gniuždymo apkrova. Nagrinėjamas modelių deformavimas, esant gniuždymo apkrovai, kartu simuliuojant senėjimo procesų ir osteoporozės poveikį, kuris pasireiškia audinio silpnėjimu. Nagrinėjami ir lyginami trys atvejai: sveiko audinio apkrovimas, vidutinio osteoporozės lygio paveiktos slankstelių sistemos apkrovimas ir aukšto osteoporozės lygio paveikto modelio apkrovimas.