CALIBRATION OF MATERIAL MODEL FOR TRABECULAR BONEVERIFIED BY TIME-LAPSE X-RAY MICROTOMOGRAPHY

摘要

The paper deals with investigation of the trabecular bone behaviour during compression test. Paper describes loading test of trabecular bone specimen using real-time Computer Tomography scanning and its simulation by Finite Element Method. Incremental loading was applied during the experiment. The tomographic images were acquired for each load step and the applied force was recorded. Model for the Finite Element (FE) simulation was obtained using the reconstruction from tomographic projections of the zero deformation state. Deformation states were reconstructed to assess the three-dimensional strain field in the microstructure and compared with results from FE simulations. For the Finite Element analysis (FEA) a proper material model is needed. Assessment of the material model was based on nanoindentation experiment. The nanoinden-tation test of the trabecular bone sample was performed and the material model was identified from FE simulation of the nanoindentation test. Material model with von Mises yield criterion and bilinear isotropic hardening was chosen. Required material constants were obtained from fitting the load-displacement curve using the least squares method. Remaining constants were directly identified from the experiment. The deformation behaviour of the FE model during the compression test was compared to the experimentally obtained response to verify the FE model.