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This paper describes the testing and constitutive model development of polyurethane foams for characterization of their material dynamic properties. These properties are needed not only for understanding their behavior, but also for supplying essential input data to foam models, which help provide design directions through simulations of foam selection for cushioning occupant head impacts against the vehicle door and upper interior. Polyurethane foams of varying densities were tested statically and dynamically under uniaxial compressive impact loading at constant velocities of various rates and different temperatures. The test results were utilized for developing a constitutive model of polyurethane foams by taking the density, strain rate and temperature effects into consideration. Uniaxial constitutive models are developed in two ways.

Currently, the three (3) methods for calculating the HIC-value are: 1) direct computation method, 2) utilization of maximization requirement approach developed by Chou and Nyquist, and 3) a partitioning technique. A method which involves the adoption of an optimization approach for HIC calculation is discussed in this study. This optimization technique, which has previously been applied to Boundary Element Method (BEM), employs an improved constrained variable metric method in recursive quadratic programming. This technique was applied to three theoretical and ten experimental acceleration pulses; the results compare extremely well with exact solution and/or other numerical methods. It is concluded that this optimization scheme provides accurate HIC calculations. A study is planned to investigate the feasibility of extending the application of this optimization technique to an integrated trim/foam/sheet metal pillar system for improved interior head impact protection study.

Successful operation of electric vehicles under Canadian conditions requires consideration of the effect of low temperature, not only on the propulsion and energy storage systems, but on the energy required for passenger heating and window defrosting. Thermal management of the propulsion battery is a primary consideration, but other factors such as the protection of the electric systems from road salt are essential. Several approaches to passenger heating and window defrosting are being studied and some systems evaluated in the test fleet. Options based on liquid fuel or all-electric methods will be discussed. The environmental advantages of EVs for winter use are considerable. EVs operating under these winter conditions, i.e., low-speed in congested traffic due to snow and ice and frequent winter accidents, have no toxic gaseous emissions which is particularly good in comparison to ICE vehicles.