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Biomedical subjects

Y C Deng

Publications and source records attributed to Y C Deng.

8 recordsLinked to original sources
PubMed1989

Anthropomorphic dummy neck modeling and injury considerations.

This study investigates the modeling of the Hybrid III dummy head and neck system and its response under impulsive loading. Two neck models were proposed, one rigid, one flexible; both give satisfactory head kinematics upon comparing to minisled test results. The flexible neck model provides a more detailed understanding of the Hybrid III neck structure behavior. It indicates that the Hybrid III neck has a torque response similar to a human neck but has higher shear response. During flexion whiplash, the torque at the occipital condyle reverses its direction at about 25 ms after impact. Since concussion may be related to the head angular acceleration, which reaches its peak value in the first 25 ms, it might be necessary to extend the existing human torque-rotation corridor to include the neck response in this region. For flexion whiplash impact, simulation results indicated that the neck injury threshold is reached before exceeding the head injury threshold as the impact velocity is increased.

Acceleration↗
PubMed1987

Response of a human head/neck/upper-torso replica to dynamic loading--I. Physical model.

A human head/neck/upper-torso replica was constructed and instrumented and its response to impact and dynamic loading was studied. The model consists of a water-filled cadaver skull; plastic vertebrae, sternum and ribs; silicon rubber disks and ligaments; and fabric muscles. The static behavior of the system under sagittal plane and lateral loading was adjusted so as to correspond to that of cadaver behavior under similar loading. The structure was loaded impulsively by the sudden arrest of a supporting sled running on a track and by direct head impact with a suspended steel ball. The measured response included the head acceleration, the disk pressures, the muscle strains, the intracranial pressures and the skull strains; the sled motion was also monitored. These data were recorded with a microcomputer and oscilloscopes; the overall system deformation was observed by high-speed cameras. The muscle contraction effects were determined with the aid of microcomputer-controlled devices including a vacuum system, solenoid valves and plastic syringes.

Acceleration↗
PubMed1987

Response of a human head/neck/upper-torso replica to dynamic loading--II. Analytical/numerical model.

A three-dimensional lumped-parameter model of the human head/neck/upper-torso was developed to predict its motion for any specified initial conditions and that could also be used to compare with the results of other investigators. This model consists of ten rigid bodies representing the head, cervical vertebrae C1-C7, T1 and T2 combined with the rest of the torso. These rigid bodies were connected by intervertebral joints described by a stiffness matrix relating the force (moment) and translation (rotation). Fifteen pairs of muscles were incorporated in the model, represented by three-point linear elements with nonlinear constitutive relationships obtained from cadaver test results. The calculated response compared favorably with human volunteer data for both flexion and lateral whiplash. However, tests on an inanimate replica of a human indicated greater flexibility than predicted by the corresponding numerical model. The difference is believed to be due to insufficient mass of the muscles incorporated in the structure.

Acceleration↗
PubMed1984

Three-dimensional response of a lumped parameter head-neck model due to impact and impulsive loading.

A numerical procedure developed previously for predicting sagittal-plane motion of the human head-neck system due to impact and impulsive loading has been extended to three dimensions. In both situations, a lumped parameter approach is employed, but the current model lumps the mechanical response of each intervertebral joint into a single force-deformation relation evaluated from mechanical properties assembled by various investigators. Computations were performed to obtain the response of the model to a two-dimensional case of flexion whiplash, to one three-dimensional case of side impact to the skull and to another involving base acceleration normal to the sagittal plane. Agreement of the kinematic variables with the results of both the previous two-dimensional analysis and experimental data from a volunteer run is satisfactory, but somewhat poorer correspondence was found for the three-dimensional predictions upon comparison with data obtained from a physical model and from a volunteer when subjected to the prescribed loading. The differences in response are attributed to higher stiffness of facet separation of the model relative both to the structure and the volunteer, to insufficient damping, as well as to substantial differences in the mechanical deformation characteristic of the components of the prototypes and the numerical model.

Atlanto-Axial Joint↗