Characteristics of Soil-Tripped Rollovers

Cooperrider, N K; Hammoud, Selim; Colwell, Jeff D.

doi:10.4271/980022

Cited by 30 publications

(6 citation statements)

References 1 publication

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“…To correct for this shortfall, a post-processing step was used to monitor the value of the vehicle's velocity and sideslip angle, β , the angle between the heading and the velocity vector of the vehicle. Previous studies have shown through experimental testing of induced rollovers, that a threshold of 45° sideslip and a minimum speed of 32.187 km/hr (20 mph) will lead to a soil tripped rollover [43,44]. During the post-processing, if a vehicle experienced 45° sideslip while the vehicle speed was above 32.187 km/hr, the traversal was marked as a rollover event.…”

Section: Resultsmentioning

confidence: 99%

Utilization of Vehicle Dynamic Simulations as Predictors of Highway Safety

Brennan

Hamblin

2007

Volume 16: Transportation Systems

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Safety is a crucial consideration in the design of roadways, yet formal tools to study roadway safety prior to construction are often quite limited. As a possible new tool, this work investigates the iterative use of vehicle dynamic simulations to study vehicle-roadway interaction in order to optimize highway design for safety. Following a discussion of the history and accuracy of vehicle dynamic simulations, a methodology of roadway geometry analysis is presented. This methodology is demonstrated by an example scenario studying the safety of a depressed median of a rural highway when there is an in-median incursion. The vehicle type, vehicle speed, vehicle trajectory, and the driver’s corrective maneuvers are all varied in a simulation-based analysis to evaluate their respective effects on vehicle behavior including vehicle orientation, trajectory, and instabilities.

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Section: Resultsmentioning

confidence: 99%

Utilization of Vehicle Dynamic Simulations as Predictors of Highway Safety

Brennan

Hamblin

2007

Volume 16: Transportation Systems

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“…In addition to the error introduced by the assumption of constant vehicle deceleration, some consideration should be given to the error introduced by assuming a prescribed roll rate function, given the variation in the shape of measured roll rate vs. time curves (Orlowski et al, 1985;Thomas et al, 1989;Cooperrider et al, 1998;Carter et al, 2002;Luepke et al, 2007). It is also recognized that the model assumes an initial roll angle of zero, when in actuality a rolling vehicle will already have rolled some amount (approximately 45 degrees) before the leading tires stop leaving marks.…”

Section: Discussionmentioning

confidence: 99%

“…The roll rate of the vehicle (ω) at each time point is generally unknown in a real world crash. For the purpose of developing a generalized vehicle dynamics model, an equation form was developed that generally matched roll rate vs. time plots measured in various vehicle rollover tests (Orlowski et al, 1985;Thomas et al, 1989;Cooperrider et al, 1998;Carter et al, 2002;Luepke et al, 2007):…”

Section: Generalized Vehicle Dynamics Modelmentioning

confidence: 99%

Trajectory Model of Occupants Ejected in Rollover Crashes

Funk

Luepke

2007

SAE Technical Paper Series

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A simple two-dimensional particle model was developed to predict the airborne trajectory, landing point, tumbling distance, and rest position of an occupant ejected in a rollover crash. The ejected occupant was modeled as a projectile that was launched tangentially at a given radius from the center of gravity of the vehicle. The landing and tumbling phases of the ejection were modeled assuming a constant coefficient of friction between the occupant and the ground. Model parameters were optimized based on a dolly rollover test of a 1998 Ford Expedition in which five unbelted anthropomorphic test devices (ATDs) were completely ejected. A generalized vehicle dynamics model was also created assuming a constant translational deceleration and a prescribed roll rate function. Predictions using the generalized model were validated against the results of the full-scale rollover test to estimate the expected error when using the model in a real world situation. The model was shown to be a useful tool for investigating possible ejection points and occupant trajectories in rollover crashes.

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“…Following are several examples of tripping mechanisms that can initiate a rollover: (1) interaction between a tire or wheel rim and pavement [6], (2) wheels furrowing into soil or sod [7,8], and (3) wheels impacting a curb [7,9]. For each of these mechanisms, the magnitude and duration of the tripping force and the manner in which that force is applied through time will vary.…”

Section: Trip Phase Motionmentioning

confidence: 99%

Factors Influencing Roof-to-Ground Impact Severity: Video Analysis and Analytical Modeling

Rose¹,

Beauchamp²,

Fenton³

2007

SAE Technical Paper Series

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This paper explores the dynamics of rollover crashes and examines factors that influence the severity of the roof-to-ground impacts that occur during these crashes. The paper first reports analysis of 12 real-world rollover accidents that were captured on video. Roll rate time histories for the vehicles in these accidents are reported and the characteristics of these curves are analyzed. Next, the paper uses analytical modeling to explore the influence that the trip phase characteristics may have on the severity of roof-to-ground impacts that occur during the roll phase. Finally, the principle of impulse and momentum is used to derive an analytical impact model for examining the mechanics of a roof-to-ground impact. This modeling is used to identify the influence of various impact conditions on the severity of a roof-to-ground impact.

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Characteristics of Soil-Tripped Rollovers

Cited by 30 publications

References 1 publication

Utilization of Vehicle Dynamic Simulations as Predictors of Highway Safety

Utilization of Vehicle Dynamic Simulations as Predictors of Highway Safety

Trajectory Model of Occupants Ejected in Rollover Crashes

Factors Influencing Roof-to-Ground Impact Severity: Video Analysis and Analytical Modeling

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