ANALYZING ROADSIDE SAFETY IMPLICATIONS OF FUTURE VEHICLE DESIGNS

摘要

To meet new Corporate Average Fuel Economy (CAFE) standards, future vehicles are expected to be more environmentally friendly and fuel efficient. In addition to introducing innovative manufacturing methods and structural modifications, automobile manufacturers are primarily adopting lightweighting technologies to meet the demands for more fuel efficient vehicles. It is seen from prior research that by focusing on lightweight (LW) designs alone, the average new vehicle could weigh 28% less in 2016 than it does today. Using LW designs is not without its challenges though. These designs represent significantly different dynamic characteristics and crashworthiness response when compared against original designs. Accordingly, it is necessary to evaluate the safety implications of these LW vehicles under impact scenarios with various roadside infrastructures. It is also necessary to ensure that the existing infrastructure can satisfy required safety standards in protecting the occupants under different crash conditions. In this paper, we adopt Finite Element Method (FEM) for modeling and simulating different crash scenarios in order to evaluate the safety implications of future LW vehicle designs. Baseline (BL) models for three vehicles - Toyota Yaris, Ford Taurus and Chevy Silverado are appropriately LW modeled with 15% (LW15) and 25% (LW25) reduction in weight, whilst maintaining structural stiffness and Center of Gravity. Numerical simulations are then performed for a 25° impact angle against three common roadside infrastructures - Concrete median barrier, Strong post W-beam guardrail and W-beam transition barrier at three different speeds - 50, 70 and 100 km/hr. The goal is to conduct a matrix of simulations in order to provide comprehensive and relative safety assessment. Barrier performance is then gauged in accordance to the MASH (Manual for Assessing Safety Hardware) criteria wherein the metrics take into account evaluation factors such as structural adequacy and occupant risk.