Integrated Evaluation of Pre-Crash Braking and Crash Injury Outcomes Using Human Body Models and ATDs

Traditionally, vehicle occupant safety research has focused on passive safety aspects like crashworthiness and occupant restraint systems. However, with the advent of Active Safety technologies such as Forward Collision Warning (FCW) and Autonomous Emergency Braking (AEB), research has expanded to include occupant kinematics during the pre-crash phase. AEB, by inducing occupant movement, often leads to out-of-position (OOP) behavior, compromising available space during the crash phase. Current Anthropometric Test Devices (ATDs) are limited in simulating occupant kinematics during the pre-crash phase, especially in the neck and torso regions. These devices are rigid and unable to replicate human body dynamics during low-acceleration events like AEB. To address this gap, Human Body Models (HBMs) such as THUMS, GHBMC, and SAFER are used to provide more biofidelic simulations. This study begins with physical vehicle trials conducted with human volunteers at various speeds to measure occupant excursion during the AEB phase. Finite element simulations were then performed in ANSYS LS-Dyna using HBMs to analyze the impact of posture changes on occupant injuries. Specifically, the study compares injuries in normal versus forward-excursed postures caused by frontal AEB, focusing on neck, chest, and head regions. Additionally, the research investigates occupant muscle activation during the pre-crash phase, as muscles contract involuntarily in response to impending impact. HBM simulations incorporating muscle activation help understand how these physiological responses influence occupant kinematics and injury severity. The findings underscore the importance of integrating active and passive safety systems to optimize occupant protection, especially when AEB is involved. This study demonstrates that value HBMs offer in the fields of Active and Passive Safety for a more comprehensive understanding of occupant behaviour and injury mechanisms.