Analysis of Vehicle Front Impact Pulse Severity in US NCAP 2020-01-0986

There have been multiple studies on the effect of vehicle impact pulses on occupant responses, and studies on the previous and current US NCAP (New Car Assessment Program) vehicle pulses. This paper analyzes 35 mph (56.3 kph) front impact vehicle pulses and occupant responses in US NCAP tests conducted by the NHTSA from 2011 to 2019. Based on the occupant response analysis, a simple generic occupant restraint force-relative displacement model has been created. This generic model captures the fundamental restraint characteristics of the vehicles in the recent years, and together with the vehicle pulse, they provide several occupant response predictors. Furthermore, this paper proposes a new pulse severity metric PSD (Pulse Severity by Displacement) based on the vehicle impact data statistics, and uses the pulse severity to compare with other pulse severity definitions. It explains the shortcomings of using the vehicle dynamic crush and TTZV (Time-To-Zero Velocity) as pulse severity metrics, and shows how improvements can be made with simple modifications. Data regression methods are used to assess relationships among different metrics and variables. The paper also provides statistics of the vehicle pulses, the trend of pulse severity and characteristics over the years.