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Impacts between passenger vehicles and heavy vehicles are uniquely severe due to the aggressivity of the heavy vehicles; this is a function of the difference in their geometry and mass. Side crashes with heavy vehicles are a particularly severe crash type due to the mismatch in bumper/structure height that often results in underride and extensive intrusion of the passenger compartment. Underride occurs when a portion of one vehicle, usually the smaller vehicle, moves under another, rendering many of the passenger vehicle safety systems ineffective. Heavy vehicles in the US, including single-unit trucks, truck tractors, semi-trailers, and full trailers, are currently not required to have side underride protection devices. The NTSB, among other groups, has recommended that side underride performance standards be developed and that heavy vehicles be equipped with side underride protection systems that meet those standards.

Frame rail design advances for the heavy truck industry provide numerous opportunities for enhanced protection of fuel storage systems. One aspect of the advanced frame technology now available is the ability to vary the frame rail separation along the length of the truck, as well as the depth of the frame. In this study, the effect of incorporating the fuel storage system within advanced technology tapered frame rails was evaluated using virtual testing under impact conditions. The impact performance was evaluated under a range of horizontal impacts conditions. The performance observed was quantified and then compared with previous testing of baseline diesel tank systems. Fuel storage system impact performance metrics over the range of crash conditions considered were quantified using virtual testing methods. The results obtained from the application of the impact performance evaluation methodology were then described.

The incidence of fire in heavy trucks has been shown to be about ten times higher under crash conditions than occurs in passenger vehicles. Fuel tank protection testing defined in SAE standard J703 was originally issued in 1954 and presently echoes federal regulations codified in 49 CFR 393. These tests do not reflect dynamic impact conditions representative of those that can be expected by heavy trucks on the road today. Advanced virtual testing of current and alternative fuel tank designs and locations under example impact conditions is reported. Virtual testing methods can model vehicle to vehicle and vehicle to fixed object impacts. These results can then be utilized to evaluate and refine fuel tank protection system design approaches.

More than 900,000 long-haul sleeper cabs are projected to be on the road by 2030. About half of heavy truck occupant fatalities occur in rollovers. This paper discusses the current status of rollover protection systems for occupants in sleeper cabs and describes the outcomes from example crashes with sleeper cab occupants. A virtual testing methodology for evaluation of current designs under rollover conditions and restraint tests utilizing dummies and humans also are described. The paper includes discussion of finite element models used and their validation. Examples of results associated with various restraint system configurations are presented. The results show that incorporating effective lateral restraint is important in providing protection to sleeper cab occupants under rollover conditions.

Rollover test equipment is of interest in the development of rollover protection system designs. The Controlled Rollover Impact System (CRIS) by Exponent and the Jordan Rollover System (JRS) from the original founder of VIA Systems represent two such systems available. The two systems represent significantly different approaches to the same problem; the CRIS utilizes a structure moving over the ground, while the JRS utilizes a rotating vehicle over a moving ground. Finite Element (FE) modeling of CRIS impacts has been presented previously. In this paper, the ability to model the JRS system is demonstrated. A Finite Element model of the JRS was created and compared with an over-the-ground rollover under the same conditions. An analysis using Finite Element models of a production and roll-caged vehicles and Hybrid III dummies with the CRIS and JRS devices under the same impact conditions then was conducted. The results of the analysis are provided and discussed.

The Federal Motor Vehicle Safety Standard 226 (FMVSS 226) ejection mitigation standard proposes to measure the performance of ejection mitigation countermeasures (like side curtain airbags) in side impacts and rollovers. An ejection impactor, consisting of a head form attached to a shaft, is propelled at the airbag system at different locations, and the ability of the system to prevent complete or partial ejection out of the side window portals is documented. The friction between the head form and airbag can affect the performance of the airbag to retain the impactor, particularly when the impactor strikes at the bottom of the airbag near the windowsill level. In this study, friction tests were conducted to measure the friction coefficients between a head form scalp material and airbag fabric, human hair and airbag fabric, and human skin and airbag fabric.

The objective of this study was to demonstrate the ability to reproduce the impact environment occurring in rollover crash tests. There are over 26,000 fatalities and serious injuries annually occurring in rollover accidents in the United States [1]. Many of these are to restrained occupants and their head and spinal injuries have been associated with contact with the roof structure. Finite element models of the Hybrid III dummy and vehicles were used to model the rollover crash tests conducted for Ford. The rollover crash tests involved a production vehicle in a baseline form and one with a roll cage added to it. The impact conditions were incorporated and the results compared with the published test results. The results show that finite element modeling can reproduce the results from rollover crash tests.

A typical production transit bus with vertical pillars of small section size, low gauge and low strength steel, exhibits extensive lateral pillar side-sway collapse (matchboxing) in rollover impacts. This matchboxing allows rollover of the bus onto its roof. LS-DYNA simulations demonstrate that roof pillars of high strength steel or inexpensive E-glass fiber reinforced polymer (FRP) pultrusions can prevent matchboxing and arrest the rollover of the bus. However, for the same space envelope, pultruded FRP pillars can be at least 41% lighter than high strength steel square tubes exhibiting the same bending moment capacity.

This paper is a part of a larger report (Friedman, Kenney, & Holloway, 2003), Impact Induced Fires & Fuel Leakage: Statistical Analysis of FARS and State Data Files (1978-2001). This larger report included a review of the literature of fire and fuel leaks in post-collision passenger vehicles from 1957 to 2003, replicated Malliaris' (1991) methodology in his landmark study of post-collision fires in the State of Michigan and FARS data, and furthered the analysis by examining post-collision fires and fuel leaks with three state accident databases-Maryland, Illinois and Pennsylvania. The current paper is focused on the conclusions and overall recommendations for data collection and analysis based on the findings from the state accident databases and FARS analyses.

The influence of fiber architecture on the strength of a composite panel for the same fiber/resin system is discussed in this paper. The attention is focused on the two failure modes, which are usually considered the most critical in designing with polymer composites, delamination and flexural failure. The investigation is carried out with the aid of a four point-bend test fixture, whose geometry only varies between the two test configurations, according to ASTM standards D2344 and D790. Investigation covers four prepreg tape laminates, namely the unidirectional, multidirectional, quasi-isotropic and cross-ply, and two woven fabrics, namely the 2×2 twill and 8-harness satin weave. Lastly, design considerations and engineering solutions adopted by Lamborghini for the development of the body of the new Murcièlago are discussed.

The use of composites in automotive applications necessarily leads to investigating the effects of attachment (joining) on the overall strength of the new configuration. Traditional joining methods used for metal-to-metal (welding) and composite-to-composite are not directly applicable in metal-to-composite structures. A testing program was initiated to examine the relative strengths of typical roof structure welded joints with alternative roof structure designs involving composites attached to metal by threaded fasteners. Frequently the attachment of a composite roof to the metal body of a vehicle includes the introduction of a gap joint with an intervening seal. Lap-shear testing was used to determine comparisons of relative joint strength between the various methods. The results of this testing are presented. The use of threaded fasteners to attach composites to sheet metal was found to dramatically reduce the joint strength relative to the welding of metal-to-metal.

The Federal Motor Vehicle Safety Standard 571.201 discusses occupant protection with interior impacts of vehicles. Recent rule making by the National Highway Traffic Safety Administration (NHTSA) has identified padding for potential injury reduction in vehicles. Head injury mitigation with padding on vehicular roll bars was evaluated. After market 2 to 2.5 cm thick padding and metal air gap padding reduced the head injury criterion (HIC) and angular acceleration compared to the stock foam roll bar padding. Studies were conducted with free falling Hybrid 50% male head form drops on the fore head and side of the head. Compared to the stock roll bar material, a nearly 90% reduction in HIC was observed at speeds up to 5.4 m/s. A concomitant 83% reduction in angular acceleration was also observed with the metal air gap padding. A 2 to 2.5 cm thick Simpson roll bar padding produced a 70 to 75% reduction in HIC and a 59 to 73% reduction in angular acceleration.

Rollover accidents account for a large number of serious to fatal injuries annually. In the past, these injuries were often the result of unrestrained occupant ejection. Subsequent to mandatory belt use laws, a larger percentage of these injuries occur inside the vehicle, and the head and neck areas sustain a substantial number of these injuries. An analytical effort to understand rollover injuries, using the field accident data of the NASS files and residual headroom as an indicator, was reported by the authors at the 1996 ESV conference in Melbourne, Australia. This paper describes the relationship between roof crush and restrained occupant injury in rollover accidents as derived from the analysis of 1988-1992 NASS files. It extends the residual headroom parameter to the entire population of head, face and neck occupants injured inside the compartment.1

A study of an existing B-pillar was conducted to examine the changes required to increase the lateral load carrying capability by a factor of ten. A finite element optimization package was used to adjust the geometric and material characteristics simultaneously while minimizing weight. The results show that the weight and cost necessary for the ten-fold improvement in lateral load carrying capability were very low. Further, the results illustrate how structural design optimization with finite element modeling can be effectively utilized to create cost effective elements for use in an integrated occupant protection system.