Biomechanical and Injury Response to Posterolateral Loading From Torso Side Airbags

Abstract

This study characterized thoracoabdominal response to posterolateral loading from a seat-mounted side airbag. Seven unembalmed post-mortem human subjects were exposed to ten airbag deployments. Subjects were positioned such that the deploying airbag first contacted the posterolateral thorax between T6 and L1 while stationary (n = 3 × 2 aspects) or while subjected to left lateral sled impact at ΔV = 6.7 m/s (n = 4). Chestband contours were analyzed to quantify deformation direction in the thoracic x–y plane (zero degrees indicating anterior and 180° indicating posterior), magnitude, rate, and viscous response. Skeletal injuries were consistent with posterolateral contact; visceral injuries consisted of renal (n = 1) or splenic (n = 3) lacerations. Deformation direction was transient during sled impact, progressing from 122 ± 5° at deformation onset to 90° following maximum deflection. Angles from stationary subjects progressed from 141 ± 9° to 120°. Peak normalized deflections, peak rates, and VCmax ranges were 0.075 – 0.171, 3.7 – 12.7 m/s, and 0.3 – 0.6 m/s with stationary airbag, respectively; ranges were 0.167 – 0.297, 7.4 – 18.3 m/s, and 0.7 – 3.0 m/s with airbag sled impact, respectively. Peak deflections were measured at angles between 99° – 135° and 98° – 125° for stationary and dynamic conditions, respectively. Because of deflection angle transience and localized injury response, both posterolateral and lateral injury metrics may be required for this boundary condition. Contrasted with flat rigid or anterolateral loading, biomechanical response to side airbag interaction may be augmented by peak normalized deflection or VCmax at 130°.

Tensile material properties of human rib cortical bone under quasi-static and dynamic failure loading and influence of the bone microstucture on failure characteristics

“…Rib fractures are a good indicator of the severity of an impact to the thorax as the protection to the internal organs such as the lungs and the heart is greatly reduced with the increasing number of fractured ribs (abbreviated injury scale, AAAM ( 2008)). Injury mechanisms for the ribs and the whole rib cage have been widely studied, either through experiments (Kent et al, 2004;Vezin and Berthet, 2009;Kuppa and Eppinger, 1998;Trosseille et al, 2008;Hallman et al, 2010;Petitjean et al, 2003;Lessley et al, 2010b) or computational simulations (Murakami et al, 2006;Lizée et al, 1998;Song et al, 2009;Robin, 2001;Vezin and Verriest, 2005;Shigeta et al, 2009;Kimpara et al, 2005;Plank and Eppinger, 1989;Ruan et al, 2003;Li et al, 2010a,b;Kimpara et al, 2006) to determine injury mechanisms and thresholds under diverse load conditions. A significant milestone was achieved in the characterization of the strength of the thorax by accounting for the geo-metrical variations in the rib cage and the rib themselves, and for the effects of biological variations such as aging (Berthet et al, 2005;Ito et al, 2009;Gayzik et al, 2008;Kent et al, 2004).…”

Modular and scalable load-wall sled buck for pure-lateral and oblique side impact tests

“…These studies have implications in the biomechanics of restraints such as side-impact airbags and loadings specific to organs (spleen, kidney). Posterolateral impact studies have been initiated by subjecting stationary PMHS (Hallman et al, 2010). Use of oblique load-wall configuration aimed at posterolateral impacts overcomes the lack of inertial effects in stationary surrogate tests.…”

Accidental Injury Analysis and Protection for Automated Vehicles

“…The individual response of a single rib was the subject of an optimization study [41]. The abdomen was validated in various tests using bar impacts with a free back [42,43], belt loading with a free back [43], airbag loading with a fixed back [43], belt loading at the mid abdomen [44,45], pendulum impact [46], organ level validation at impact [47], lumbar flexion [48], lateral impact [49] and side airbag loading [50]. The pelvis was validated in lateral compression at the acetabulum [51][52][53] and pubic symphysis [54].…”