Article Number: 102 | VC6 | VC5 | VC4 | VC3 | Post Date: September 8, 2020 | Updated: September 8, 2020
How can I specify rolling resistance values to my tractor and trailer separately?
Independant trailer braking is also discussed in this Knowledge Base post. You have few ways to decelerate your vehicle with rolling resistance values in Virtual CRASH. Perhaps the easiest way is to use the “wheels separately”. Once you enable this option for your deceleration sequence, you’ll see a list {ratio 1, ratio 2, …} become visible. Recall from the User’s Guide (VC6 | VC5 | VC4 | VC3), ratio 1 is the driver side front, ratio 2 the passenger side front, ratio 3 is the driver side wheel on the next axle back, and so on. We highly recommend you read this chapter before continuing.
Simply specify the percentage braking you would like for the given wheel. Recall, each ratio is going to cause a longitudinal tire force \( F = N \cdot f\mu \), where \(\mu\) is the adhesion value, \(f\) is the fraction of braking to be used (between 0% to 100%), and \(N\) is the static equilibrium normal load on the tire. The \(f\) value is what is being specified by each ratio input.
Here, for our deceleration sequence entry, we set our rolling resistance values to 2% for the tractor’s front axle and 15% for the drive axles.
For our trailer, we set our rolling resistance values to 2%. Note, you must disable “use tow car sequence”. Not doing so will cause the trailer’s \(f\) values to be determined by the implied acceleration/deceleration rate of the tractor’s sequence input. This is not what we want in this case.
Tags: Rolling resistance, braking trailers.
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