Chung-Kyu Park

A Study of the Rear Seat Occupant Safety using a 10-Year-Old Child Dummy in the New Car Assessment Program

This paper describes how the National Highway Traffic Safety Administration (NHTSA) conducted a total of 28 frontal crashes in the New Car Assessment Program (NCAP) involving the 10-year-old child Hybrid III dummy. The 10-year-old child dummy was in the rear seat. All types of vehicles (passenger cars, sport utility vehicles, vans and pick-up trucks) were tested to assess the effect of restraint systems such as booster and pretensioner on the rear seat occupant. In this study, the readings of the 10-year-old child dummy in rear-left and rear-right seat positions are examined. This paper applies a possible 5 star rating system, based on head and chest readings of the 10-year-old dummy. The paper also assesses the safety performance of rear seat occupants and the effect of the restraint systems on a child in the rear seat. This paper suggests that a star rating for rear seat occupants is independent of the present ratings for the driver and front adult passenger in NCAP. This paper examines the dynamic signals of the vehicle and the child dummy in the 28 NCAP crashes. The examination figured out the relationship between vehicle pulse and dummy pulse compared with 5-4 star-rated vehicles or 3-1 star-rated vehicles based on the rear seat occupant responses. The child dummy signals are compared for different passenger vehicles. For example, the comparison of high head acceleration and low chest acceleration case to low head acceleration and high chest acceleration case is performed for vans.

Crashworthiness of composite inserts in vehicle structure

Composite inserts are a well-known and innovative technology in the automotive industry used to improve safety, NVH (noise, vibration, and harshness) and fatigue life of vehicles, as well as to reduce vehicle weight and manufacturing cost. In order to study the crashworthiness performance of composite inserts in a vehicle structure, a three-point bending test of simplified steel-composite combined beam structures is considered. The beam structure in this investigation has a double-hat section. Epoxy-based structural foam and 33% short glass fibre reinforced nylon insert are considered as composite fillers for the two empty beam sections. Four cases, based on the different combination of composite materials inserted in the beam sections, are considered. The test results show that the composite insert greatly contributes to improvement of the energy absorption of beam structure. The force–displacement (F–D) curves of bending tests, the deformation behaviours of beam structures and the failure modes of composite inserts are shown and analysed to understand the effects of composite inserts to the crashworthiness of the beam structure in a bending condition. The numerical study was performed to develop a practical finite element (FE) model of the steel-composite combined structure.

Crashworthiness and Numerical Analysis of Composite Inserts in Vehicle Structure

The objective of this research is to understand the crashworthiness performance of composite inserts in vehicle structure and to improve the numerical model of steel-composite combined structure for providing better prediction in the design process of composite inserts. A simplified steel-composite combined beam structure is used for three-point bending tests. Epoxy-based structural foam and 33% short glass fiber reinforced nylon composite insert are considered as composite fillers in empty sections of double hat-type steel beam structure. Four cases based on the different combination of composite materials are considered. In the series of physical three-point bending tests, the force-displacement (F-D) curves and material behaviors are investigated. The test results show that the composite insert greatly contributes to improve the crashworthiness of beam structure as well as to reduce the vehicle weight. Especially, the adhesive failure of structural foam and the brittle fracture mode of composite insert are greatly influential to the resistance force level in the three-point bending test. In the numerical study, a concern is to build a practical FE model, which can be used in full-scale vehicle crash simulation. The parametric study shows that parameters related to material and contact types are critical to simulate the adhesive failure of structural foam and the brittle fracture of composite insert. The final simulation results show good agreement with the physical tests. Language: en