Finite Element Modeling Of Human Neck With Muscle Activation

Head and neck injuries are the most common type of injury in traffic accidents.As the safety performance of modern vehicles is increasingly improving, the risk ofsevere injuries that involve head-neck-complex is decreasing dramatically. However,for the sake of the fast growing population of vehicle, the moderate injuries of neckare prevailing. Consequently, it is necessary to study the injury patterns of thesemoderate neck injuries. The methodology of injury biomechanics consist of two parts:experimental research and mathematical research. Experimental researches could al-ways provide us the most realistic dynamics of human. Yet the experiments concern-ing human subjects are difficult to implement, and the measuring methods are limitedfor ethical reasons. The information acquired from experimental researches is ratherinsufficient. Mathematical researches could well complement the experimental studies.A detailed mathematical model of head-neck-complex with high biofidelity couldsimply calculate the physical quantities that could not be directly measured in ex-periments. Therefore, it is a necessity to develop a mathematical head neck complexmodel basing on the detailed geometry information as well as accurate mechanicalproperties of biological tissue.This study is focusing on the development of a human head-neck complex finiteelement (FE) model, which is based on accurate geometric information of human neck.The active response of skeletal muscles is also incorporated.Firstly, the mechanical properties of skeletal muscle were investigated. The sta-bility and accuracy of skeletal FE model was confirmed by reconstructing a tensileexperiment of mammal skeletal muscle. The constitutive laws for skeletal as well asits parameters were also identified in the reconstruction. Basing on the magnetic res-onance images from a50percentile male adult, a geometric model of human neckmuscles was established. The geometric model was then transformed into the space ofbase head neck FE model with the help of kriging interpolation method. On the basisof mapped neck muscle geometrical model and the constitutive laws determined above,a human neck muscle FE model was developed and integrated into the base FE modelof head-neck-complex. The complete FE model of human head-neck-complex wasvalidated by reconstructing15G frontal impact experiment conducted by Ewing et alin1968. Finally the difference between active response and passive response of de- veloped FE model was compared. Parameter studies concerning neck muscles’ me-chanical properties were conducted to illustrate the advantages and flaws of currentFE model. A study of comparing the response between validations with and withoutT1rotation was added to confirm the importance of defining T1rotation during thefrontal impact validation.This study shows that sharing the nodes of solid elements with Hill beam ele-ments is a feasible implementation of muscle response. The developed muscle FEmodel could be stabilized in certain range by proper control. The dynamics of estab-lished head-neck FE model are consistent with that of volunteers. The head-neck FEmodel could be utilized in studies of head and neck injuries. However, there are sev-eral defects need to be improved. The active response of neck muscles has a great in-fluence on the head-neck dynamics in15G frontal impact, and could reduce the injuryrisk of head and neck. This study preliminarily explored the FE implementation ofskeletal muscle and developed a head-neck FE model with high biofidelity. The re-sults could serve the injury studies of head and neck.