Development of a New Human Thoracic Equivalent Model during Frontal Impact

Human thoracic injury under frontal collisions is an inevitable problem in vehicle safety research. Compared with the Multiple Rigid-Body Models (MRBMs) and Finite Element Human Body Models (FEHBMs), Mathematical Equivalent Models (MEMs) can not only provide important data but also improve the research efficiency. The current thoracic MEMs usually adapted the mechanical isolation method to isolate the thorax from the human body; therefore, the effects of the head, neck, and lower body internal organs on the mechanical responses of the thorax are not considered. In this article, a new thoracic MEM, named as Improved Consistent Lobdell Model (ICLM), is developed based on the concentrated mass-spring-damping system to consider the energy absorbed by the deformation of the internal soft tissue and the motion hysteresis of the head, neck, and lower body. Thorax equivalent stiffness curve predicted by the ICLM has a good fit with the corridor obtained by the Post-Mortem Human Subjects (PMHS) experiments under the medium-speed pendulum impact. Based on the parametric and sensitivity analysis, the values of parameters in each subsystem of the ICLM are adjusted to improve the accuracy of different impact tests predicted by the ICLM. The thoracic responses predicted by the adjusted ICLM under the medium-speed pendulum impact were basically consistent with that predicted by the Total Human Model for Safety (THUMS). The relative errors of maximum chest force (F_max) and maximum chest deflection (D_max) between the adjusted ICLM model and THUMS are 0.57% and 0.86%, respectively. The adjusted ICLM has good biofidelity and can be applied in the field of automotive engineering in the future.