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Technical Paper

Snowmobile Cornering and Acceleration Data from On-Snow Testing

2015-04-14
2015-01-1431
Snowmobile acceleration, braking and cornering performance data are not well developed for use in accident reconstruction. Linear acceleration and braking data published by D'Addario[1] gives results for testing on 4 snowmobiles of various make and model. This paper presents the results of on-snow tests performed in 2014 which include acceleration and cornering maneuvers that have not been published previously. Maximum and average cornering speeds and corresponding lateral accelerations are presented for turns of radius 20, 35 and 65 feet (6.1, 10.7 and 19.8 meters) on level, packed snow. Performance values for acceleration, braking, and cornering are determined in tests with and without a passenger. Results of linear acceleration and braking tests were found to be comparable to the previously published work. The data are useful in snowmobile accident reconstruction for certain types of snowmobile motion analyses.
Technical Paper

Rollover Testing of Recreational Off-Highway Vehicles (ROVs) for Accident Reconstruction

2011-04-12
2011-01-1117
This paper presents results of full-scale instrumented rollover testing on ROV type recreational vehicles. Five tests were conducted using two instrumented side-by-side ROVs at speeds between 20 and 32 mph on unpaved surfaces. Each test vehicle was brought to speed and released, allowing remote steering inputs to initiate turn sequences resulting in rollover. Accelerations were determined using x, y, and z axis accelerometers mounted at the vehicle CG and recorded using a robust data acquisition system. Roll rates were measured using a rotation rate sensor. Roll rates and key acceleration events are presented for each test. Mapping and measurement of the test site includes photography and digital survey of resulting tire marks, impact marks and gouging. Documentation and reconstruction of test roll sequences includes roll rates, vehicle positions and velocities, peak accelerations by impact, and scratch mark and damage examination. These are included in the appendix .
Technical Paper

Roadway Asphalt Damage Analysis: Dynamic Evaluation of Gouge Forces

2010-04-12
2010-01-0047
In reconstruction of on-roadway vehicle accidents, roadway surface gouges and the forces and energy attributed to the related vehicle components become important keys to resolving accurate accident reconstructions. Accounting for the forces applied to vehicle components and the energy dissipated from such forces can be helpful where supporting data exists. Roadway gouge forces vary depending upon such factors as road surface temperature and the velocity of the gouging mechanism. Other factors that may affect roadway gouges are road surface age, differing gouge tooth geometry, and road surface construction but these factors are not addressed in this paper. Calculation and summation of individual contact forces and contact energies can be significant in the accounting of accident vehicle motion reconstruction. This paper expands upon findings presented in SAE 2008-01-0173.
Technical Paper

ATV Rollover Resistance: Testing of Side-By-Side ATV Rollover Initiations

2010-04-12
2010-01-0522
Rollover crashes involving side-by-side ATVs and injuries related to these crashes represent an increasing percentage of the total population of ATV injury crashes. Unlike traditional ATVs, side-by-side ATVs are designed to carry two passengers abreast and usually include roll bars and seat belts. Most side-by-side ATVs are also designed to carry a limited payload in a rear cargo bed. Primary target uses for these vehicles include a combination of utilitarian tasks and recreational activities. Modifications by consumers often incorporate additional equipment that can change the mass balance and handling characteristics of the vehicle. This paper explores the resistance of these vehicles to roll as affected by the variables commonly applied to automotive crashes. Static Stability Factor (SSF) and Critical Sliding Velocity (CSV) are calculated and compared to findings from previously published work on roll resistance.
Technical Paper

Fatal and Severe Injuries in Rear Impact; Seat Stiffness in Recent Field Accident Data

2008-04-14
2008-01-0193
A decade ago, James, et.al. published a detailed study of the available NASS data on severe rear impacts, with findings that “… stiffened or rigid seat backs will not substantially mitigate severe and fatal injuries in rear impacts.” No field accident study has since been advanced which refutes this finding. Advocates of rigidized seat backs often point to specific cases of severe rear impacts in which MAIS 4+ injuries are associated with seat back deformation, coupled with arguments supporting stiffer seatback designs. These arguments are generally based upon laboratory experiments with dummies in normal seating positions. Recent field accident data shows that generally, in collisions where the majority of societal harm is created, yielding seats continue to provide benefits, including those associated with whiplash associated disorders (WAD).
Technical Paper

Roadway Asphalt Damage Force Analysis for Accident Reconstruction

2008-04-14
2008-01-0173
In reconstruction of on-roadway vehicle accidents, tire-road surface friction coefficient, mu (μ), can be estimated using a variety of available data. Common ranges and values for μ are used in calculations forming the foundation for most accident reconstruction techniques. When the roadway surface is gouged or disrupted by vehicle components, accounting of dissipated energy can be successful where supporting force data exists. Roadway gouge forces can vary widely depending upon such factors as road surface construction, surface temperature, and the velocity and geometry of the gouging mechanism. Such dissipated energy can be significant in accounting of total reconstruction energy. This paper presents experiments aimed at quantifying gouge force by controlled pavement gouging tests.
Technical Paper

Derivation of Vehicle-to-Vehicle Frontal Crash Pulse Estimates from Barrier Crash Data

2008-04-14
2008-01-0174
The BSAN crash pulse model has been shown to provide useful information for restraint sensing evaluation and for structural force-displacement studies in flat fixed rigid barrier (FFRB) crashes. This paper demonstrates a procedure by which the model may be extended for use with central and offset vehicle to vehicle (VTV) crashes through appropriate combinations of vehicle parameters.
Technical Paper

Load Path Considerations for Side Crash Compatibility

2007-04-16
2007-01-1176
Heavier, larger pickups and SUVs are bound to encounter lighter, smaller passenger vehicles in many future accidents. As the fleet has evolved to include more and more SUVs, their frontal structures are often indistinguishable from pickup fronts. Improvements in geometric compatibility features are crucial to further injury prevention progress in side impact. In corner crashes where modern bullet passenger car (PC) bumpers make appropriate geometrical overlap with target PC rocker panels, concentrated loads sometimes disrupt foam and plastic bumper corners, creating aggressive edges. In situations where sliding occurs along the structural interface, these sharp edges may slice through doors, panels and pillars. End treatments for such bumper beams should be designed to reduce this aggressive potential.
Technical Paper

Pulse Shape and Duration in Frontal Crashes

2007-04-16
2007-01-0724
Understanding of events within the history of a crash, and estimation of the severity of occupant interior collisions depend upon an accurate assessment of crash duration. Since this time duration is not measured independently in most crash test reports, it must usually be inferred from interpretations of acceleration data or from displacement data in high-speed film analysis. The significant physical effects related to the crash pulse are often essential in reconstruction analyses wherein the estimation of occupant interior “second collision” or airbag sensing issues are at issue. A simple relation is presented and examined which allows approximation of the approach phase and separation phase kinematics, including restitution and pulse width. Building upon previous work, this relation allows straightforward interpretation of test data from related publicly available test reports.
Technical Paper

Development of Pole Impact Testing at Multiple Vehicle Side Locations As Applied to the Ford Taurus Structural Platform

2006-04-03
2006-01-0062
A test method was developed whereby repeated pole impacts could be performed at multiple locations per test vehicle, allowing a comparison of energy and crush relationships. Testing was performed on vehicles moving laterally into a 12.75 inch diameter rigid pole barrier. Crush energy absorption characteristics at the different locations were analyzed, and the results compared to test data from broad moving barrier crashes and available crash tests with similar pole impacts. Crush stiffness characteristics for narrow impacts at various points on the side of the Taurus vehicle platform were documented. Factors encountered during the research include the importance of rotational energy accounting and uncertainties related to crush energy related to induced deformation. The findings show that the front axle and A-pillar regions are much stiffer than the CG and B-pillar areas to narrow rigid pole impact.
Technical Paper

Accident Reconstruction for Rear Pole Impacts of Passenger Cars

2006-04-03
2006-01-0899
While vehicular rear pole impacts are rare, they do occur, and can be very serious. General accident reconstruction methods, which derive vehicle stiffness values from rear barrier crash tests, over-predict the impact speed for these types of pole impacts. Thirteen pole crash tests were run into the rear-ends of four 4-door, front-wheel drive sedans. Repeated crash testing was used on three of the vehicles. Two 1988 Acura Legends, which have one of the highest stiffness values from FMVSS 301 Rear Compliance crash testing, a 1988 Honda Civic, which has one of the softest rear-end stiffnesses, and a 1986 Ford Taurus were tested. The repeated crash testing methodology was validated using one of the 1988 Acura Legends and a previously published Ford Taurus test. Residual crush was measured using maximum crush, point-to-point, longitudinal full-width, and longitudinal reduced-width methodologies. Crush was found to be linearly related to impact speed.
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