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Conceptually, a steering wheel mounted air cushion is inflated before the upper torso of the driver significantly interacts with the cushion. However, this might not be the case for some seating postures or vehicle crash environments which could cause the driver to significantly interact with an inflating cushion. These experiments utilized several environments to study the interaction between an inflating driver air cushion and mechanical surrogates. In these laboratory environments, the measured responses of mechanical surrogates increased with diminishing distance between the surrogate's sternum and the steering wheel mounted air cushion.

This study identifies important parameters that influence the basic response mechanics of a compressible column steering assembly. Energy can be absorbed either by column compression and/or steering wheel deformation, depending on relative deformation force. Neither column compressive force nor steering wheel deformation force are uniquely defined but depend on several parameters. Steering wheel deformation force is dependent on occupant load distribution. The force necessary to compress the column differs from the column EA element compressive force due to inertial and geometric considerations. For our test conditions and the components we studied, off axis impact resulted in initial steering wheel deformation with the wheel and column sharing energy absorption. Axial impact resulted in almost negligible wheel deformation and the column was the energy absorbing component.

Post-crash conditions of a car's steering system, when properly measured and documented, provide an insight to the interaction between the driver and the steering system that occurs during a frontal car crash. Steering system conditions were investigated in two interrelated phases: 1. Deformation of the wheel rim, spokes, and hub, and 2. Compression resistance force of the steering column. Two devices were developed to document the “crash loading” response of these two segments of the car's steering system. One device was designed to measure the deformations of the steering wheel and the other the force required to further compress the steering column. An initial test series on 19 “crashed” cars “field tested” the devices, developed the test techniques and procedures needed for in-depth studies, and formulated necessary data handling methods and data collection forms.