Scott R. Webb

Physical and chemical characterization of airbag effluents

OBJECTIVE This paper describes a study aimed at characterizing the exposure to physical and chemical by-products from the deployment of airbag restraint systems. DESIGN, MATERIALS AND METHODS Specifically, the levels of particulates and the composition of gases and bag fabric speed were measured in the passenger compartment following deployment of either a drivers side or drivers side/passengers side airbag system. MEASUREMENTS A Fourier transform infrared analyzer (FTIR) and chemiluminescence analyzers were used for gas analysis, a cascade impactor and gravimetric filter measurements for aerosol determination and high-speed films to determine fabric speed. MAIN RESULTS AND CONCLUSIONS The measured gases were found to be within the recommended guidelines for human exposures, but no guidelines exist for particle exposures of this magnitude (150-220 mg/m3) but short duration. High-speed films were also taken of the deployments to obtain an estimate of the fabric speed as it leaves the module. The maximum average speed for both types of airbag was approximately 100 mph and in both cases average speeds ranged from lows near 50 mph to highs of over 200 mph.

Investigation Into the Noise Associated With Air Bag Deployment: Part I - Measurement Technique and Parameter Study

A new system consisting of commercially available pressure transducers and microphones was assembled and a new software package was developed. This system allows the analysis of pressure-time data using two analysis methods and criteria proposed in the early 1970s. A series of experiments using this system was run over a four year period to investigate the parameters that affect the impulse noise associated with a deploying air bag. For the covering abstract of the conference see IRRD 879189.

Impact Performance of Magnetorheological Fluids

As part of an emerging effort in what is now termed the area of mechamatronics [1], an effort was begun to assess the suitability of MR (magnetorheological) material based devices for impact energy management applications. A fundamental property of MR materials is that their yield stress alters almost instantaneously (and proportionally) to changes in the strength of an applied magnetic field. Based on this property, MR based devices, if found suitable, would be desirable for impact energy management applications because of attendant response tailorability. However, it was identified that prior to adopting MR based devices for impact energy management applications several key issues needed to be addressed. The present study focused on one of the most significant of these, the verification of the tunability of the response of such devices at stroking velocities representative of vehicular crashes. Impact tests using a free-flight drop tower facility were conducted on an MR based energy absorber (shock absorber) for a range of impact velocities and magnetic field strengths. Results demonstrated that over the range of impact velocities tested — 1.0 to 10 m/s — the stroking force/energy absorption exhibited by the device remained dependent on and thus could be modified by changes in the strength of the applied magnetic field.Copyright

S-Rail Sled Testing With Deceleration Sled

This paper considers the effects of rotary draw bending on structural crashworthiness. We impacted tested aluminum alloy tubes in s-rail bending, using either 2.0 mm or 3.5 mm thickness, and bend radius of either 152.4 mm or 191 mm. This report documents and summarizes the test setup using the GM R&D Deceleration Sled to achieve this, with emphasis on later correlation with numerical simulation. Theoretical and numerical analyses were used to help with design setup. Forces and moments found in the tests were very consistent, suggesting good test setup design. We also found that using the longest tube section at the constrained end prevents inboard rotation and contact between the two s-rails.© 2005 ASME

Axial Crush Drop Tower Testing of Hydroformed Sections

This report summarizes the drop tower testing of initially circular straight aluminum tubes that had been hydroformed to a square section with round corners. Drop tower test conditions and test setup were determined for the AlMg3.5Mn aluminum alloy circular (76.2 mm outside diameter) tubes of either 2.0 or 3.5 mm thickness, which had been hydroformed into a square tube with corner radii of 38.1 (unformed), 33, 30, 27 and 24 mm. To initiate test setup, theoretical equations were found to be reasonable indicators of displacement and load cell requirements. Four-lobe symmetric modes were found for the square tubes, and three-lobe asymmetric modes for the circular tubes. The number of folding half-waves of seven for 3.5 mm tubes, and thirteen for 2 mm tubes, was generally overpredicted by theory. Aluminum end plates that were welded onto the tube ends allowed for fast test setup, but may have resulted in some sliding and tipping of the drop tower. The tubes were found to have decreasing average crush force with smaller corner radii, esp. for the 3.5 mm thick tubes.Copyright