| FEA(Finite Element Analysis,FEA)is a computing algorithm used to study complex physical models of geometric or load conditions.Its basic principle is to discrete the model into many small units,every single unit load cases was analyzed,and then all units of the model are unified calculated to obtain the overall case load model,which is very suitable for solving complex engineering mechanics.Due to the complexity of the human body structure,FEM(Finite Element Method,FEM)as a new research tool has been widely used in the field of biomechanics.There are researches discovered that Oral and maxillofacial injuries have a high incidence rate because of its exposed position.The traditional method in study of oral and maxillofacial trauma,the animal model,the body or artificial material model is limited to the cost of medical ethics,supply instability,repeatability limitation and other reasons,can not fully meet the needs of research.Finite element analysis method,because of its low cost,high repeatability,and other advantages is regard to a good method,make up for the lack of traditional methods described above.Our previous experiments established some important modeling of maxillofacial bone,with which we finished finite element analysis of gunshot wounds and blast injuries,provide new ideas to injury mechanism of maxillofacial trauma and injury evaluations,but because of the limitations of the model can not reflect the role of the soft tissue in trauma.Therefore,we urgently need a complete finite element model including hard and soft tissues of the head and face,as a research tool of oral and maxillofacial digital simulation platform of our research team.Research methodsHealthy adult male volunteers’ head CT(Computer Tomography)data was imported into Mimics14.0 software,the bone tissue,subcutaneous soft tissue and skin tissue were classified respectively for image segmentation,3D reconstruction,and surface meshing.The surface mesh models were substantiation in Geomagic Studio software,and volume meshes were divided by Hypermesh software.Finally,three three-part model were assembled in Solidworks software.In the LS-DYNA software,we setted the impact conditions,to test the simulation performance of the model.Results1.We get three-dimensional reconstruction images and surface mesh model of the craniofacial bone,soft tissue and the skin tissue,the number of which are: 895074,1023146,332869.The models are complete and the number is great.2.We completed the entity reverse generation of surface mesh models,CAD solid model of the three-part structure and the complex model were got respectively.A complete head finite element model consisting of volume body was obtained,the number of the model is 214 250,the number of nodes is 411 920,mesh number of bone,soft tissue and skin tissue were 72926,121856,19648;nodes number were 131266,243712,36942 sequentially.3.We completed the impact injury simulation to test the model,the stress cloud imagines of hard and soft tissues were obtained successfully,observed the dynamic changes in bone tissue.And the results are similar to clinical practice.ConclusionIn this study,three-dimensional head finite element model entirely composed of volume meshes was successfully established,and the dynamic simulation performance of the model was tested to determine the results of the model,ensured that the actual injury is similar to the model simulation of impact injury.While we get the CAD solid model of human head,we can combine computer simulation with 3D printing technology to produce simulation skull,to provide new tools to cranial and maxillofacial trauma simulations. |
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