The Role of Seat Belt Restraint System Components in Rear-End Collisions 2021-01-0912

The role of seatback strength on occupant motion during rear-end collisions has been a focus of scientific investigation for decades. Despite being an integral component of the occupant restraint system, the role of seat belt restraints and the potential effect of various seat belt restraint system components, like pretensioners and latch plate design, on occupant motion and injury potential during rear-end collisions has received less attention. This study identifies and highlights what is currently understood about the role of seat belt restraints and components in rear-end collisions from the existing literature in detail for the first time. Previous studies that have investigated the role of pretensioning in occupant motion and loading did not provide detailed assessments of pretensioning effects on webbing loads and displacement, nor did they discuss the relationship between pretensioner deployment and latch plate design. Static pretensioner deployment tests were conducted to quantify and evaluate webbing movement with anchor and/or retractor pretensioner deployments as well as to compare sliding latch plate (SLP) and dynamic-locking latch plate (DLLP) designs. Results from the static deployments in this study suggest that retractor pretensioner deployment followed by an anchor pretensioner deployment removed the most webbing from the seat belt system and created the highest lap belt loop tension, independent of the latch plate design. In some scenarios, absent pretensioner deployments in rear impacts crashes, the unidirectional functionality of the DLLP could potentially provide more pelvic restraint and coupling to the seat than a SLP to mitigate ramping and occupant excursion.