Development And Injury Analysis Of A 3-year-old Child Occupant Thoracic Finite Element Model

In vehicle accidences,people paid more and more attendance to child occupant protection.Due to different constitution with an adult,including softer ribs and immature organs,it is more easily for a child to get thoracic injury,or even get killed in a crash,because thorax is the most significant part of a human body to maintaining regular general circulation,breathing cycle,digestion etc.For more powerful protection,some pertinent measures against thoracic dangers are necessitous.Child crash finite element models are more conventionally used for occupant safety performance research for child restraint system.In order to construct a 3-year-old child occupant finite element model,MIMICS is utilized to extract point cloud models of every organs from CT image of a 3-year-old child volunteer;GEOMAGIC is used to do the smoothing and patches dividing to make geometry models;HYPERMESH is applied to assembling,adjusting and meshing,during which TRUEGRID is also used to mesh;and finally utilize PAMCRASH to set material properties for all the parts.According to real impactor tests,an impactor finite element model is constructed to reconstruct the real tests.The constructed 3-year-old child occupant finite element model is verified to be valid by comparing the output impact force versus time curve,thoracic deformation versus time curve,and the cross curve for both.To simulate a vehicle front impact accident,a simplified child safety seat model is made referring common configuration of child safety seat for 3-year-old child recently.15 tests are conducted using the assembly of 3-year-old child occupant finite element model and child safety seat model.Conclusions are drawn by analysing peak stress on organs:(1)Child safety seat must be equipped for 3-year-old occupant.(2)Anterior installation is more effective for thoracic soft organs of 3-year-old occupant than posterior installation.(3)To make sure to lighten every soft organs,width of shoulder belt can be adjusted according to occupant’s constitution and endurance of normal human organs.(4)In the interval of[8%,14%],extensibility should be high enough.However,exorbitant extensibility is unsuitable for the child who has weak heart and lungs.(5)In the interval of[0°,10°],angle of seatback should be large enough except the child who has defects on bronchus or pulmonary.