Evaluation Of Skull Fracture Under Blunt Loading By Finite Element Method

Skull is an important organ to protect human brain tissue.When the head bears the blunt force load,skull is the first organ to bear the injury and the most serious injury.Therefore,it is necessary to study the injury of skull.The main purpose of this study is to explore the degree of skull injury caused by different loads and further infer the injury mechanism of skull injury.It is difficult for traditional research methods to accurately reproduce the damage process,and to have a comprehensive understanding of the deformation of each part and the change of each parameter in the process of loading.In this paper,the finite element method is used to simulate the process of skull injury under blunt force loading,to clarify the results of different loads,to analyze the influence of different factors on skull injury,and to provide scientific basis for the protection of head injury and forensic examination.This study will be based on the 50th percentile adult head finite element model established by the injury biomechanics research center of Tianjin University of Science and Technology.In order to make the results more accurate and effective,the research mainly focuses on the damage of skull structure.The structure of the model is improved to some extent:some units with large aspect ratio were deleted and re-divided,and the thickness of some parts of the skull was adjusted to make it fully conform to the true anatomical structure.After the adjustment of these details,the corresponding simulation experiments of Yoganandan’s corpse experiment are carried out,and the experimental results prove the validity of the model.In blunt force injury cases,the type of blunt force is very important to the occurrence and severity of the injury.Based on the blunt instrument types in blunt instrument injury cases summarized by the public security department,combined with the later research on the size parameters and material parameters of each type of blunt instrument,45 common types of blunt instruments were determined.Based on the blunt force information summarized above,a typical finite element tool library of blunt force tools is established by using 3D modeling software and finite element preprocessing software.The formation of the tool base is one of the bases of finite element simulation and contrast test.In blunt force cases,different groups of people can cause different degrees of injury,so it is necessary to set certain loading conditions in the finite element simulation.Therefore,this paper designs and implements a group of experiments to collect the impact velocity of different groups of people.There are two conclusions in the experiment:one is to determine the maximum hitting speed range of different people under different conditions,and provide data basis for the following simulation boundary conditions;the other is to explore and summarize the impact of different factors(gender,age,height,weight,hitting posture and blunt type)on the hitting speed.After the modification of the finite element head model,the establishment of the finite element blunt force model and the determination of the loading conditions,the damage of the skull under the blunt force load is analyzed and studied.The effects of different loading conditions(impact position,impact speed and blunt force type)on the skull damage are analyzed and the corresponding database of the skull damage results and damage conditions is established.