ABSTRACT
Objective To construct a three-dimensional (3D) dynamic head-neck finite element model which accords with the anatomical structure, and study its dynamic responses under the external force. Methods By using the neck CT images of a Chinese adult male volunteer and obtaining the 3D cervical point cloud data, the finite element model of cervical spine was established using ICEM-CFD and HyperMesh software. This model, including vertebrae, intervertebral discs, facet joints, ligaments and cartilage tissues, and combining with the established and verified head finite element model, was assembled as human head-neck finite element model with detailed anatomical structures. Results The model was validated by data of head-neck axial impact experiments reported in previously published literature. The simulation results showed that the neck deformation, head acceleration, head force and injury positions were preferably consistent with the experimental data. Conclusions The established 3D dynamic finite element model can be used to study head-neck dynamic responses and damage mechanism in the fields of traffic safety and impact injuries.
ABSTRACT
Objective To construct a three-dimensional (3D) dynamic head-neck finite element model which ac cords with the anatomical structure,and study its dynamic responses under the extemal force.Methods By using the neck CT images of a Chinese adult male volunteer and obtaining the 3D cervical point cloud data,the finite element model of cervical spine was established using ICEM-CFD and HyperMesh software.This model,including vertebrae,intervertebral discs,facet joints,ligaments and cartilage tissues,and combining with the es tablished and verified head finite element model,was assembled as human head-neck finite element model with detailed anatomical structures.Results The model was validated by data of head-neck axial impact experiments reported in previously published literature.The simulation results showed that the neck deformation,head acceleration,head force and injury positions were preferably consistent with the experimental data.Conclusions The established 3D dynamic finite element model can be used to study head-neck dynamic responses and damage mechanism in the fields of traffic safety and impact injuries.
ABSTRACT
The effects of an arm lifting movement (ALM) on maximum vertical jumps with all but the ankle joints fixed (propelled only by plantar flexion) were studied in five subjects. ALM increased flight time, but did not alter maximum angular velocity of the ankle before takeoff. Holding 4kg dumbbells in their hands enhanced the effect of ALM on flight time. ALM increased the maximum force and the force at the onset of plantar flexion. Elbow angle recordings showed that both arms were accelerated before or around plantar flexion onset, and decelerated mainly after takeoff. In another series of experiments, we measured the vertical component of head and hand acceleration with accelerometers. ALM produced positive acceleration of the head after takeoff, which was related to negative acceleration of the hand. The results suggest that ALM increased flight time by enhancing plantar flexion torque under suppression of ankle angular velocity before takeoff. We discussed the relationship between this suppression and different acceleration between the arms and the body except the arms.