Due to high-rate loads placed on the torso during motor vehicle crashes, the human thorax is commonly injured, and resulting rib fractures are linked to fatalities. The goal of this study was to explore the variation in strain modes, magnitudes, and rates of rib levels 3-8 in a dynamic, distributed loading scenario in a series of hierarchical tissue states of 50 th percentile males. Strain modes varied by rib level where superior level ribs demonstrated tension on the cutaneous surface, and inferior ribs, rib 8 specifically, experienced compression. Peak strain and peak strain rates varied between rib levels at the anterior and posterior locations (p<0.0001). Intact thoraces generally demonstrated higher peak strain values across rib levels and eviscerated thoraces exhibited higher peak strain rates across rib levels. Rib levels 4-6 experienced higher peak strain than other levels at the anterior location while level 8 experienced higher peak strains at the posterior location. After whole thorax testing, ribs 4-7 were removed and tested to failure in anterior-posterior bending. Peak strains from individual rib testing did not vary between rib levels 4-7 at anterior or posterior locations (p=0.17 and p=0.79, respectively). This study revealed local deformation patterns across ribs while maintaining the structural integrity of the thorax in distributed loading as well as component testing to failure across rib levels. The results from this study can be used to further understand rib connections during loading events and help to define accurate rib-specific properties to improve the biofidelity of computational human body models.
Keywords:
deformation; rib level; strain modes; tissue states; thorax