Finite Element Analysis of the Mechanical Deformation of Three-dimensional Human Fingertip Model from CT Images

Abstract

The mechanical deformation of a human fingertip when pressing on a flat plate was numerically analyzed using a three-dimensional human fingertip model constructed from CT images of human index finger. The fingertip model was constituted of three parts : a distal phalanx bone, skin/subcutaneous tissue, and a nail. The analyses were carried out at 34 to 200 kPa of seven Young's moduli, and at 0.3 to 0.5 of five Poisson's ratios. The numerical results were compared with the reported experimental data of human fingertip. The numerical results showed that the deformation around the nail and at the distal fingertip was generated subsequently to the large deformation of pulp. The numerical deformation results showed a similar pattern to the experimental data. From the numerical results, we calculated the length of the contact area on lateral view and the width of the contact area on axial view in order to qualitatively estimate the deformation. By comparison of numerical and experimental results, there were no unique values of Young's modulus and Poisson's ratio to express the experimental results. These results suggest that the epidermal, the dermal, and the fat tissue constituting the skin/subcutaneous tissue may influence to the mechanical deformation by these different contributions