Influence of Ribcage Shape on Thoracic Response of Anthropometrically Correct 5th Percentile Female Finite Element Model

An anthropometrically correct 5 percentile female FE (THUMSD F05) model was developed based on scanned MRI images (Ghosh et al. - 2014). The challenge in development of anthropometrically correct model was to modify existing CAD geometry to meet the requirements of anthropometrically correct surface model. The metrics identified for anthropometric validation were based on 44 dimensional measurements based on CAESER Project. The difficulty existed in modifying internal anatomy of human body to align with the outer surface. This led to modification of ribcage geometry of THUMSD-F05. The developed model was extensively validated for frontal (Kroell & Nahum) and lateral impact (ISO 9790) load cases. The model in thoracic region predicted good biofidelity (Biofidelity Rating = 6.95) score in lateral impacts, but, for frontal impact was not good because of lower chest deflections. One of the principal indicators identified which influences thoracic biofidelity was geometry of ribcage. The geometric assessment of ribcage was conducted based on shape of ribcage to assess chest deflection response. The behaviour of ribcage response was analysed for frontal pendulum impact load cases (Kroell (1971) at 13.23 m/s & Nahum (1970) at 4.2 m/s). Investigations suggested that biofidelity of ribcage has strong correlation to geometry of ribcage.