Development of a Variable Deceleration Rate Approach to Rollover Crash Reconstruction

Rose, Nathan A.; Beauchamp, Gray

doi:10.4271/2009-01-0093

Cited by 10 publications

(6 citation statements)

References 29 publications

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“…In our model, we theorize that friction due to relative sliding between the vehicle perimeter and the ground is the mechanism by which the roll rate increases early in the rollover, in agreement with Chen and Guenther [4] and Rose and Beauchamp [15]. We propose that once the tangential velocity of the vehicle's perimeter catches up to the translational velocity of the vehicle's center of gravity, relative sliding between the vehicle's perimeter and the ground ceases, consistent with the findings of Rose and Beauchamp [15]. During the later part of the rollover, we propose that the vehicle rolls without sliding and decelerates both translationally and rotationally at a rate governed by geometric factors.…”

Section: Introductionsupporting

confidence: 82%

“…However, it is much simpler than an impact-by-impact level reconstruction. Rose et al [13,15] presented a detailed impulse-momentum analysis that can be applied to individual ground impacts. Their equations are considerably more complex than ours because they incorporate vertical motion, but both approaches utilize the same physical principles.…”

Section: Discussionmentioning

confidence: 99%

“…Historically and up to the present, vehicle speed during the tumbling phase of a rollover crash has been calculated using a simple slide-to-stop formula [4-5, 8-9, 11]. Recently, investigators have suggested that the accuracy of rollover reconstruction can be improved using a variable deceleration rate approach [3,15]. There is good empirical support for such an approach.…”

Section: Introductionmentioning

confidence: 99%

“…In this paper, we propose a model for rollover crashes in which the rotational and translational dynamics of a rolling vehicle are coupled to each other based on the average frictional forces developed during ground contacts. Somewhat similar models were proposed by Chen and Guenther [4] and Rose and Beauchamp [15]. The Chen and Guenther [4] model utilized a constant deceleration approach to model the translational velocity of the vehicle.…”

Section: Introductionmentioning

confidence: 99%

“…In the later part of the rollover, they theorized that the opposite phenomenon occurs: the roll rate decreases because the tangential velocity of the vehicle perimeter exceeds the translational velocity of the vehicle's center of gravity, and the relative sliding between the ground and vehicle results in frictional forces that slow the roll velocity of the vehicle until it reaches its point of rest. Rose and Beauchamp [15] presented several approaches to modeling a variable deceleration rate during rollovers. These approaches were something of a hybrid between modeling empirical data and applying impulse-momentum equations they had previously developed for modeling individual ground impacts in rollovers [13].…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

An Integrated Model of Rolling and Sliding in Rollover Crashes

Funk¹,

Wirth²,

Bonugli³

et al. 2012

SAE Technical Paper Series

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Rollover crashes are often difficult to reconstruct in detail because of their chaotic nature. Historically, vehicle speeds in rollover crashes have been calculated using a simple slide-tostop formula with empirically derived drag factors. Roll rates are typically calculated in an average sense over the entire rollover or a segment of it in which vehicle roll angles are known at various positions. A unified model to describe the translational and rotational vehicle dynamics throughout the rollover sequence is lacking. We propose a pseudocylindrical model of a rolling vehicle in which the rotational and translational dynamics are coupled to each other based on the average frictional forces developed during ground contacts. We describe the model as pseudo-cylindrical because vertical motion is ignored but the ground reaction force is not constrained to act directly underneath the center of gravity of the vehicle. The tumbling phase of a rollover is modeled in three distinct phases: an initial brief airborne phase between roll initiation and the first ground contact, an early phase in which relative sliding between the perimeter of the vehicle and the ground causes the roll rate to increase, and a later phase in which the vehicle rolls without sliding and the roll rate decreases. In the early phase, the average vehicle deceleration is higher and is governed by sliding friction. In the later phase, the average vehicle deceleration is lower and is governed by geometric factors. Model predictions were fit to data from 12 well-documented rollover crashes in order to derive empirical values for the model parameters. In 11 out of the 12 rollovers studied, the model predictions matched the actual results with good accuracy. The results validate the underlying physical principles of the model and provide data that can be used to apply the model to real world rollovers. The proposed model provides a physical basis for understanding vehicle dynamics in rollovers and may be used in certain cases to improve the accuracy of a rollover reconstruction.

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Section: Introductionsupporting

confidence: 82%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%