Development and Injury Analysis of a 3-Year-Old Child Abdominal Finite Element Model with Detailed Anatomy Structure

Children are the vulnerable groups in traffic accidents, so understanding injury mechanism based on their physiological anatomy characteristics is very important for more effective prevention. The post-mortem human subjects are rarely used for biomechanical experiments due to regulatory and ethical concerns. Therefore, finite element (FE) modeling becomes a significant approach to inform tissue-level mechanical responses by exporting the strain or stress. This study provides a high biofidelity FE model of a 3-year-old child abdomen and it could be used to parametrically study the injury mechanism, which is very valuable to developing protection devices and proposing the injury criteria of children abdomen. In this research, a 3-year-old child abdominal finite element model with detailed anatomy structure is developed which consists of 273,322 nodes, 194,684 hexahedral solid elements, and 118,549 shell elements. A simulation test is implemented to validate the FE model according to the child cadaver tests conducted by Ouyang et al. The results show that the simulation curve of impact force-abdominal deformation is inside the corridor obtained from cadaveric experiment, which suggests a validity of FE Model. And then, the FE model is used to analyze the injury mechanism through rotating the impactor 30 degrees clockwise (-30°) and counterclockwise (+30°) respectively along the vertical direction of its velocity. The results indicate the sensitivity of internal organs to blunt impact through comparing the strains of different visceral organs and analyze their injury threshold when the crash by the impactor happens head-on or from the rotating angle of ±30°. Human abdomen is asymmetric so that the deformation location and degrees of damage will be different when it is struck from different directions. If the impactor strikes the child on the right side, the liver is much easier to get injured; if the abdomen is struck on the left side, the stomach and the spleen become most vulnerable. While if the impact happens head-on, the child's abdomen can bear the force evenly to effectively reduce the injury risks of different visceral parts.