The Study Of Dynamic Response And Injuries Of Pilot’s Neck During Emergency Ejection Under High G Loading

With the development of aviation technology in various countries today,fighter aircraft have made great strides in terms of performance and flight equipment.However,the high G loads in complex aviation environments and the huge acceleration impact during ejection can cause damage to the pilot’s neck,which may even affect his life in severe cases and cause huge economic losses to the country.Therefore,it is of great importance to study the motion pattern and biomechanical response of the pilot’s head and neck during ejection under high G loads and the risk of neck injury.In this paper,a new head-neck finite element model is developed on the established neck finite element model,and the model is validated by applying the material properties under dynamic loading to establish a muscle-free finite element model with a combination of muscular finite element and rigid body,and a typical dynamic loading simulation is performed on the model.The validation results show that the simulation data of the model is in general agreement with the experimental data,which proves that the model can effectively respond to the kinematic and mechanical response of the human head and neck under dynamic loading.The validated model was used to further investigate neck injury during pilot ejection under high G loads.The main study elements and results are as follows.(1)Suitable for modelling both with and without muscles in a shock environment.The head-neck axial fall test by Nightingale et al.was used to simulate and validate the realism of the muscle-free model,and to study the motion state of the neck and fracture damage during axial fall to analyses and understand the mechanism of axial neck impact injury.Further simulation and validation of the kinematic response of the with-muscle model using a car front-to-back crash test.(2)Kinematic response of pilot muscle activation to the neck during emergency ejection.A muscle activation curve was developed to simulate the neck muscle activity during pilot ejection.It was found that early muscle activation of the pilot during emergency ejection improved neck stability;sustained high G-loads resulted in increased forward neck flexion and reduced stability,and G-loads were proportional to the magnitude of forward neck flexion,disc stress and NIC injury.(3)The effect of pilot helmet and seat tilt on neck injury during emergency ejection.By building helmets with different masses and centers of gravity and seats with different inclination angles,the movement of the pilot’s head and neck during ejection is simulated.The increase in helmet mass significantly alters the pilot’s head and neck posture and increases the risk of disc injury and ligament strain;the rearward shift of the helmet’s center of gravity reduces neck stability and leads to posterior extension,affecting disc degeneration and ligament damage;the seat tilt increases the risk of neck injury and produces significant forward motion,increasing the angle of neck rotation and the height of the anterior disc edge,affecting the pilot’s back muscle fatigue and ligament damage.Strain risk.In conclusion,this paper uses a head-neck finite element model to simulate the initial process of pilot emergency ejection,investigates the kinematic response of the neck under this condition and makes injury risk analysis and recommendations in relation to the state of neck muscle activity,different seat and helmet designs.