| The development of automotive and high-speed traffic made people's lives more convenient, following security problem. The death in traffic accidents around the world are about 120 million every year, in the United States, the death in car crash is the major fatality for children and young men. In China,107193 traffic accident happened,29866 people death,128336 people injury in the first half of 2009, direct financial loss 410,000,000 Chinese Yuan. Statistic also show that traffic accidents in United States is the first major cause of non-normal deaths in the age of 3 to 34 years old, which is about 40000 people dead in car crash in 2005, the head injury, neck injury and thorax injury are the major cause of death.Head and neck injuries are the most frequent severe injury resulting from traffic accidents. Neck injury mechanisms are difficult to study experimentally due to the variety of impact conditions involved, as well as ethical issues, such as the use of human cadavers and animals. Finite element analysis is a comprehensive computer aided mathematical method through which human head and neck impact tolerance can be investigated. A representative finite element human neck model would allow the assessment of the injurious effects of different impact conditions and enable the development of injury protection criteria in the automotive industries. This paper reviewed the articles regarding to using finite element analysis (FEA) model to study neck injury mechanisms and methodology validation. A three-dimensional finite element model established based on the human anatomical radiological image data can be implemented into the finite element analysis software including PAM-CRASH, NASTRAN, LS-DYNA etc. After comparisons and necessary adjustments are made to the model, the model will be able to predict the risk of head and neck injuries in a crash event, which is difficult to achieve experimentally. Once validated, the mathematical model can help understanding injury mechanisms and quantify mechanical parameters related to a specific impact event so that injury tolerances can be formulated.Automobiles allow us to move both farther and faster, however, the speed and weight of vehicles became an inherent safety hazard to their occupants and other road users, more than 1.2 million people die annually on world's roads. In the U.S., motor vehicle related crashes are the number one cause of death for people in the age group between 4 and 34 and account for more than 40,000 deaths each year. In addition, the brain, neck, and thoracic injury are the main death reason, biomechanical investigation worked for finite element model to develop crashworthy cars, in this paper, the neck finite element model were reviewed for vehicles safety research in the future.Head injury is the most frequent type of injury experienced by all seriously injured road users, especially car occupants. This remains true even with the introduction of enhanced restraint technology into all new cars and with the high levels of seat belt use. Most numerical simulation models of vehicle occupants, including finite element models, are based on rigid multi-segment systems resembling current Anthropometric Test Devices (ATD). As the human body's responses to impact are still very different from the responses of current ATD's, models of human body parts or segments are needed to obtain more realistic information about each body part's responses in crash events and to analyse various impact situations.Mathematical models are valuable tools in the study of trauma. They can be used to predict body response to injury-producing conditions that cannot be simulated experimentally, and they can predict responses that cannot be measured in surrogate and animal experiments. Most important, mathematical modeling is the only means by which valid experimental animal and cadaveric data can be extrapolated to living man. Finite element analysis appears to be the most appropriate technique for analysing the complex geometrical and mechanical properties of human structures. Limitations to finite element modelling in the past were due to the assumptions and approximations incorporated in those models. These simplifications were necessary as finite element methods and CPU were restricted.The accurate representation of the anatomically specific geometry in the finite element model enhances its function as predictive tool for skull fracture and brain injuries. With the aim of the head model we will study and gain insights to the biomechanics of head injury by simulating the real head injuries experienced in the automotive crash environment. The analysis was performed with the with the FE code PAM-CRASH, an explicit, large deformation, Lagrangian dynamic finite element program that is used widely for dynamic crash simulation and for nonlinear structure analysis. The implicit method of Finite Element Analysis is the classic method of solution in simulation, however the calculation speed of implicit method is slow, in this paper, the explicit method which is more effective and suitable the human tissue and large strain impact in traffic accident, through several times attempt and set, was developed to simulate the human head-neck injury response. The new non-linear visco-hyperelastic material model was deduced and utilized in human brain material presentation to simulate the variable strain rate in traffic accident. To analysis the neck sub-failure injury, we build more detailed neck finite element model and study the capsule strain in rear impact, validated the test result and represented the accident scenes. A optimization method was developed to deduce the all the brain test in the last 50 years through reversing engineering, although these tests was in different loading condition, such as compression, simple shear, in different shape, such as cylinder, cube. The biggest concern for finite element model designer is the relationship between strain rate and strain-stress curve, a series of equation was developed based on the assumption that the strain-stress curve was governed by strain rate in the test, one is about viscoelastic parameterβwhich is linear to the strain rate, the other is viscoelastic modulus G which is power function of strain rate. We validate this result in human brain model and predict the brain displacement in craniotomy because of acceleration of gravity, the simulation prediction have well agreement with the realistic MRI image after the craniotomy. We set the material as the No.77 MAT in LS-DYNA solution. |
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