Search Results

This paper relates human oblique head-neck kinematics to human frontal and lateral head-neck kinematics for three subjects of varying anthropometry. Head-neck kinematic response to indirect impact acceleration for an oblique test is compared to the superposition of the head/neck behavior of appropriate frontal and lateral tests for the same subject. The results have important implications in terms of the complexity required in the design and validation of omni-directional biofidelic crash test manikins and mathematical models of human head-neck response.

The sensitivity of biomechanical models to parameter estimation errors is crucial in determining the reliability of the dynamic estimates provided by these models. For evaluating the risk of head and neck injury from indirect impact (inertial loading), the forces and torques at key anatomical locations are important dynamic quantities. For human volunteers, these variables are estimated using head/neck models incorporating measured kinematic time traces and several indirectly measured mechanical and geometric parameters (e.g., the head center of gravity). In this paper, the sensitivity of estimated forces and torques at the occipital condyles to variations in head/neck geometric and mechanical properties, initial head positioning, and input kinematics is illustrated using a single fixed link model. Using anthropometric X-ray and fitted inertial response data from human volunteers, these forces and torques are estimated for two standard geometric/mechanical datasets.

Injuries associated with impact acceleration forces are a major source of loss in both military and civilian transportation. The testing of impact protective devices under operational conditions is primarily done using anthropomorphic manikins such as the Hybrid III. As part of its Impact Injury Prevention program, the Naval Biodynamics Laboratory is studying human volunteer2 and manikin head-neck response to whole-body acceleration. These data are being used to develop validated models for predicting human head-neck response from manikin response for a wide range of impact acceleration scenarios. For the -Gx, +Gy and +Gz vector directions, key linear and angular acceleration variables from selected sets of human experiments were fit using least-squares polynomial splines. The spline parameters are functions of the latency and amplitude of the peaks of the acceleration variables and are well-predicted from the initial head position and the sled acceleration profile.