Mathematical and Experimental Analysis of Buckling Behavior of Femur Implanted with 3D Printed Scaffolds

In this numerical, experimental, and statistical study, the critical buckling analysis of the femur implanted with 3D bioprinting scaffolds was numerically carried out utilizing ANSYS WORKBENCH software including finite element methods. Each femur was modelled under fixed-fixed boundary conditions and test ranges for the calculations were conducted in accordance with Taguchi L8 orthogonal array. In the statistical analyses, the first determining factor was decided as the scaffold number, whereas the second determining factor was considered as scaffold type. The scaffolds were produced using polycaprolactone (PCL) and polycaprolactone/hydroxyapatite (PCL/HAp) in 3D bioprinting technology. Experimental analyses were carried out to explain the differences between numerical and statistical results and to describe the mechanical properties of the scaffolds in the numerical modelling. In the experiments, morphological, chemical, and mechanical analyses were carried out utilizing scanning electron microscopy, Fourier-transform infrared spectroscopy, and tensile test, respectively. To determine the impact and importance level of the scaffolds on the critical buckling behavior of the implanted femur, analyses of Signal-Noise (S/N) ratio and variance were performed. According to the results obtained, increasing HAp leads to an increase in the mechanical properties of the scaffolds and the maximum critical buckling load are calculated utilizing femur implanted with the PCL/HAp scaffolds. The increase in scaffold number causes the decrease in buckling loads and thus the optimum design of the femur was achieved using single scaffold with PCL/HAp content. The most efficient determining factors were assessed to be scaffold number with 97.85% impact and scaffold type with 2.12% impact, respectively. In addition, the positions and contents of the scaffolds and femur geometry play a critical role on the buckling behavior. This study may be utilized as a guide paper that can provide positive ideas for surgical operations on healing and repair of bone defects.