Analysis into Injury Mode of Rib Fracture Based on Finite Element Method

This study is intended to provide a visual and quantifiable auxiliary technology for analysis of rib fracture injury mode. The rib fracture caused by boxing and chest compression is simulated by the finite element method: (1) The fist model is set to hit the left chest of THUMS4.02 (Total Human Model for Safety 4.02) at the speed of 6m/s. (2) The pressing hammer model is set to presses the precordial region of THUMS4.02 with a vertical downward force of 400 N. Distribution and morphology of rib fractures shown by the simulation results were compared, and the injury mechanism of the two was analyzed from the perspective of biomechanics. The simulation results are compared with those reported in the literature. The simulation results show that: (1) Shape and distribution characteristics of rib fractures: the shape of the broken ends of rib fractures caused by boxing is inward bending, and the fractures are distributed at the direct hitting positions of the ribs. The shape of the broken ends of rib fractures caused by chest compression is outward bending, and the fractures are distributed in the nondirect stress areas of the ribs. (2) Biomechanical response characteristics: when boxing the chest, the strain is concentrated in the position of the boxing ribs. Compressive stress is generated on the outer side of the rib at the striking position, and tensile stress is generated on the inner side. When pressing the chest, in addition to the strain distribution at the pressing position, there is another obvious strain distribution at the front line of the rib axillary on the pressing side of the chest. The lateral surface of the rib at the axillary front line generates tensile stress, and the medial surface causes compressive stress. The literature supports the simulation results, suggesting that the finite element method can be used to realize visual and quantifiable auxiliary analysis and interpretation of the injury mode of rib fracture.