The Finite Element Model Construction And Injury Analysis Of A 3-year-old Child Occupant Lower Extremity

In recent years,some related standards like the ’Motor vehicle children occupant use restraint systems’(GB27887-2011),’motor vehicle safety technical conditions’(GB7258-2012)are implemented in China,but still lacking a legal on using of child safety seats compulsory.At present the research about children occupant head and chest injury prevention are increasing,which can provide data support for the related law in the futurebut study on lower limbs protection is extremely few.This research applies finite element(FE)method to create a high biological lower extremity model of a 3-year-old occupant and uses it to simulate impact injuries.This study extracted lower limbs geometric models of skeletons,muscles and skins from child CT image.Referring to the standards in FMVSS213,ECE R44 and C-NCAP,as well as current standard for car seat for a 3-year old child,the model was adjusted into sitting posture,then create meshing with finite element.During constructing the finite element model of long bone,the growth plate was extracted according to the CT image and growth plate anatomy studies to.The accomplished FE model consists of 24 muscles,3 long bones,patella,foot bone,tendons,ligaments,fat and skin tissue,including 84187 elements and 83697 nodes,with high biological simulation.This FE model was used to study the influence on the lower limb injury by growth plate,in the growth plate setting bending test and shear test,each of which included two models,one with growth plate and the other one without growth plate.Two kinds of FE model were used to simulate collision experiment in the same condition.The result shows that the existence of the growth plate will greatly affect the lower limb injury result.The difference position of long bone fracture and ligament damage is significant.At the same time,the paper discusses the femoral mechanical characteristics of hip varus patients.By building four femur models with different HE angle(Hilgenreiner epiphyseal angle),the force of the femoral neck and research the development trend of the illness was contrasted.The result shows that the greater HE Angle makes the greater shear stress in the femur internal jugular side and the greater shear stress makes the illness more serious.In this paper,the research result of domestic children occupant lower limb injury research and for the development of damage protection technique has certain reference value.It plays significant practical role in exploring the mechanism of injury of growth plate and hip varus illness further.