Application of a digital prototype for CT-based bone strength analysis

The application of image data is one of the main approaches to creating digital prototypes of inhomogeneous medium elements. The article discusses the method of finite element (FE) analysis based on the use of computed tomography (CT) data of bone organs subjected to external loads. Based on the distribution of the material density in the volume, the geometry of the sample was restored by constructing an FE mesh. The calculations were made on the basis of a three-dimensional isoparametric FE of a continuous medium with a linear approximation of the geometry and displacement field. The data on the medium permeability were taken into account when integrating the local stiffness matrix. The purpose of the study is to describe the general technique for constructing a numerical model that allows static calculation of objects with a porous structure based on their CT data. Kinematic loading was used as boundary conditions. The analysis of the obtained results was carried out by constructing computational and post-processing grids. The qualitative assessment of the simulation results was based on the values of the normalized energy error. In the model problem, a three-point bending of a pig anterior bone sample was considered. The results obtained by numerical calculation were compared with data from a full-scale experiment. The relative error of the results ranged from 3 to 15%. The area of crack formation, determined from a full-scale experiment, was explained by the results of numerical simulation, which showed the occurrence of values exceeding the yield strength for bone material in this area. The obtained estimates reflect not only the effectiveness of the proposed approach, but also the consistency with bending test data. Moreover, the method turns out to be less resource-intensive and more efficient in terms of calculation time relative to existing approaches.