Characterization of human ribs under dynamic impact loads: Finite Element simulations and experimental validation
Caractérisation de la fracturation dynamique des os de la cage thoracique : simulations numériques et validation expérimentale
Résumé
The objective of this study is to characterize the mechanical behavior of isolated porcine ribs subjected to dynamic impact through experiments and numerical simulations. The porcine rib was used as a human surrogate rib in order to develop an adapted methodology for the human rib. A three Split Hopkinson Pressure Bar (SHPB) setup for three-point bending tests was used. An ensemble of 20 tests data was considered to be comprehensible for experimental characterization, thereby, showing an influence of strain rate on both time for fracture and amplitudes of force response. A three-dimensional porcine rib model was generated from the DICOM images of High-Resolution peripheral Quantitative Computed Tomography (HR-pQCT) scans. Material properties interpolated using power law regression equations based on apparent density were assigned
to the numerical rib. A modified elastic-viscoplastic constitutive law, capable of considering the effects of strain rate was elaborated. An incremental and stress-state dependent damage law, capable of considering effects of strain rate on fracture propagation, non-linear damage accumulation and instabilities was coupled to the constitutive law. The proposed Finite Element model is able to predict satisfactory force-displacement curve and fracture patterns of the tested ribs indicating that the developed numerical model may be used to investigate the fracture behavior of human ribs under dynamic loads.
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