An evaluation of occupant dynamics during moderate-to-high speed side impacts

The present study examined trends in occupant dynamics during side impact testing in vehicle models over the past decade. “Moderate-to-high” speed side impacts (delta-V ≥15 km/h) were analyzed. The Insurance Institute for Highway Safety (IIHS) side impact crash data was examined ( N = 126). The test procedure involved a moving deformable barrier (MDB) impacting the sides of stationary vehicles at 50.0 km/h. Instrumented 5th-percentile female SID IIs dummies were positioned in the driver and left rear passenger seats. Occupant head, neck, shoulder, torso, spine, and pelvis/femur responses (times histories, peaks, and time-to-peak values) were evaluated and compared to injury assessment reference values (IARVs). The effects of delta-V, vehicle model year, vehicle body type, and occupant seating position on dynamic responses were examined. The vehicle lateral delta-Vs ranged from 15.9 to 34.5 km/h. The MY2018-2020 demonstrated lower peak dynamics than MY2010-2013, for the driver head acceleration (53.7 ± 11.3 g vs 46.4 ± 11.6 g), shoulder lateral forces (1.7 ± 0.7 kN vs 1.5 ± 0.2 kN), average rib deflection (29.8 ± 8.3 mm vs 28.4 ± 6.2 mm), spine accelerations at T4 (51.4 ± 23.4 g vs 39.6 ± 5.9 g) and T12 (56.3 ± 18.5 g vs 45.2 ± 9.6 g), iliac forces (1.9 ± 1.0 kN vs 1.2 ± 0.9 kN), and acetabular forces (1.9 ± 0.8 kN vs 1.3 ± 0.5 kN). The driver indicated statistically higher dynamic responses than the left rear passenger. Higher wheelbase vehicles generally showed lower occupant loading than the smaller vehicles. In conclusion, a reduction in occupant loading and risks for injury was observed in vehicle models over the past decade. This provides further insight into injury mechanisms, occupant dynamics simulations, and seat/restraint design.

Automotive Laminated Side Glazing Rollover Performance When Subjected to Roadway Abrasion and Occupant Loading

Destructive testing of commercial automotive movable laminated side glass was conducted to document the occupant retention characteristics of this glazing system in quarter-roll crashes with a prolonged slide distance. That is, in some overturns a vehicle will slide to a halt on its side with a window adjacent both to an occupant’s position and to the moving roadway. It is known by field experience that this situation can result in injurious ejection of the occupant through the adjacent window if the window is constructed of tempered glass and the window has fractured. When tempered glass fractures, the window disintegrates and fully opens the portal. With the laminated side glazing that is used on some passenger vehicles, fracture of the inboard and outboard glass plies will not necessarily cause the “sandwiched” PVB interlayer to be compromised. This PVB interlayer allows the glass plies to remain in place and resist the sliding interaction. This diminishes the ejection hazard that is associated with tempered side glass. The three drag tests described within this technical paper used a single model of sport utility vehicle driver’s position door and factory installed laminated side door glass. The testing replicated the interaction of the exterior surface of the laminated glass against the moving roadway while the glazing was pre-fractured and the interior glass ply was subjected to significant simulated occupant loading. These conditions ensured contact of the exterior glass ply against the moving abrasive roadway. The detached and slightly modified driver’s door was pulled at near highway speed over a substantial distance against abrasive asphalt, simulating a rollover accident with the side of the vehicle sliding to halt. The results of these tests show that the exterior surface of the glazing, primarily consisting of the hard ceramic SiO2, is sufficiently wear resistant and durable to wear but not rupture or pull out of the peripheral channel. This testing shows that laminated glass is the superior glazing material for this accident mode from an occupant containment perspective.