Variations in Dynamic Weight Transfer (Nose-Dive)

Question on 3D Simulation/msmac3D/HVOSM and other 3D Simulation models
brian
Posts: 499
Joined: Tue Jul 14, 2009 10:52 am

Variations in Dynamic Weight Transfer (Nose-Dive)

Post by brian »

Q: Papers/research on Variations in Dynamic Weight Transfer (Nose-Dive) Between Wet & Dry Conditions?

The following is dry braking only and for only 3 vehicles, but can add to yourinformation database.
SAE paper 2006-01-1563 "Quantifying the Change in Ride Height Due to Braking: Brake Dive Test Data", Shawn P. Ray, Trevor M. Newbery and John A. Koziol
ABSTRACT
  • The concept of brake dive is not new and most drivers are aware of this phenomenon. However, no known data is available to quantify the amount of change in vehicle height during braking. Often investigators involved in under-ride/over-ride collisions or relatively low speed collisions are faced with questions such as, "How much does the front bumper dip during braking?" or, "Is it likely that the relative bumper height mismatch is due to preimpact braking?" This paper will provide the results of field testing aimed at providing answers to these and associated questions. The study will also review the factors that affect brake dive and the parameters under which these factors can be determined or be reasonably estimated. We consider how these factors can be used to predict the amount of change in bumper height.
VEHICLES TESTED
  • COMPACT CAR
    2005 Toyota Matrix XR, front wheel drive, 4-door hatchback, 4-cylinder, 1.8 liter engine, automatic transmission. This vehicle was not equipped with antilock (ABS) braking.
    MID-SIZE CAR
    2005 Chrysler Sebring LX, front wheel drive, 4-door sedan, 4-cylinder, 2.4 liter engine and automatic transmission. This vehicle was not equipped with antilock (ABS) braking.
    SUV
    2005 Ford Explorer XLT, four wheel drive, 4-door, sport utility, 6-cylinder, 4.0 liter engine and automatic transmission. This vehicle was equipped with 4-wheel anti-lock (ABS) braking.
SUMMARY
  • The Toyota Matrix brake dive plateau is approximately 2 inches and the average maximum is approximately 2.8 inches.
    The Chrysler Sebring brake dive plateau is approximately 2.3 inches and the average maximum is approximately 3.9 inches.
    The Ford Explorer brake dive plateau is approximately 2.5 inches (variable with ABS active) and the average maximum is approximately 3.8 inches.
CONCLUSION
  • The maximum brake dive of the selected vehicles varied from 2.3 inches (5.8 cm) to 4.3 inches (10.9 cm). The tests also indicate that the amount of brake dive is relatively independent of the initial speed.
    In non-ABS equipped vehicles, during the latter stages of braking, after the car enters a skid, the change in bumper height leveled off to a brake dive plateau of constant value. This value was less than the initial peak brake dive
PLEASE NOTE: In the following charts, The total time of each plot is different. The actual shape of the response is similar, the non-ABS has a flatter plateau
brake dive time histories.jpg
brake dive time histories.jpg (29.54 KiB) Viewed 2894 times
brake dive TH 2.jpg
brake dive TH 2.jpg (29.87 KiB) Viewed 2894 times
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