Load Distribution-Specific Viscoelastic Characterization of the Hybrid III Chest

This paper presents a load distribution-specific viscoelastic structural characterization of the Hybrid III 50^th percentile male anthropomorphic test dummy thorax. The dummy is positioned supine on a high-speed material testing machine and ramp-and-hold tests are performed using a distributed load, a hub load, and a diagonal belt load applied to the anterior thorax of the dummy. The force-deflection response is shown to be linear viscoelastic for all loading conditions when the internal dummy instrumentation is used to measure chest deflection. When an externally measured displacement (i.e., a measurement that includes the superficial skin material) is used for the characterization, a quasilinear viscoelastic characterization is necessary. Linear and quasilinear viscoelastic model coefficients are presented for all three loading conditions. The elastic functions show that, for a given displacement, the diagonal belt loading condition generates the highest elastic force, followed by the distributed loading condition, and the hub loading condition. It is concluded that the area of force application is of secondary importance and that the specific structures engaged (e.g., the shoulder assembly) are more important in dictating the structural response.