Evaluation of puncture resistance force of microneedle by nonlinear FEM analysis and experimental validation

Abstract

In recent years, a minimally invasive medical needle is required. The development of such a fine needle requires evaluation of puncture resistance force. We have developed various microneedles and conducted the puncture experiments to evaluate their resistance force against an artificial skin made of silicone rubber. In this study, it is attempted to reproduce the puncture experiment by FEM simulation, in which accurate three dimensional (3D) models of needle and skin are constructed, and the conditions of material properties, model size, puncture distance, puncture speed, etc. are set to the same ones as the experiments. As a commercially available nonlinear FEM software, LS-DYNA was employed. The results of FEM analysis and those of experiment were compared to estimate what extent they are matched. As a result, the tendency of the load curve, i.e., transition of resistance force with respect to puncturing distance, and the state of skin deformation were well matched, showing the possibility of FEM analysis to reproduce the experiment. The error of resistance force between analysis and experiment was 20% at most. It is expected that the parameter study would be possible, in which the performance of needle is evaluated by changing the parameters, e.g., its size, shape, how to insert it to the skin, etc.

Keywords

• microneedle
• finite element method analysis
• puncture resistance force
• skin deformation
• arbitrary lagrangian and eulerian method