Effect of 3D isotropic resolutions of sequenced images on natural vibration properties of trabecular bone

The voxel based finite element (FE) method used to obtain primary data for non-invasive imaging techniques has emerged as a major focus of interest in several disciplines such as medicine, mechanics and material engineering for solving micro and nano-scale problems. Owing to the fact that, voxel based FE models are directly affected by parameters of imaging techniques such as Computed Tomography (CT) and Magnetic Resonance Imaging (MRI), the consequences of these effects on the natural vibration analysis of structures having complex geometry in micro scale, are investigated in this study. In this context, voxel based FE models are obtained using Micro-CT imaging data that has three different resolutions of vertebral trabecular bone tissue. Furthermore, resolutions of image data sets are artificially increased and equalized for evaluating voxel based FE models that are free from FE size effects. Natural vibration characteristics of voxel based FE models are investigated not only numerically but also including associated mode shapes. Unpredictable vibrational behavior for various voxel sizes, is, thus, revealed. Element size effects of voxel based FE models are considerably different from the effects on structural components with regular prismatic shapes. Obtained results show that, investigated parameters have a crucial influence on the natural vibration behavior of trabecular bone tissue which is selected as an example of complex geometries. Modal behaviors that are effective in micro local regions, but less in the whole body, where there are possibilities for working with approximate geometry without considering the micro structure have been observed. Moreover, the results are new from a theoretical point of view, and they also represent the importance of quality in imaging data, which, in practical applications must be taken into consideration.