Cornering Stiffness Table Example

When a tire is orientated at an angle not equal to its direction of motion, a side force acts perpendicular to the plane of the wheel. The relation is nearly linear for small slip angles. The relationship that defines side force as a function of slip angle makes use of the tire cornering stiffness. The SMAC program calculates tire side forces based on a nondimensional side force function whereby the small-angle properties of the tires become progressively "saturated" at larger angles. The cornering stiffnesses of the individual wheels are input separately in the SMAC program. For additional information, please see the msmac Input Manual section entitles DISCUSSION: Cornering Stiffness.

The msmac program requires the user to input a cornering stiffness for small slip angles on M-SMAC cards 6 and 7.  

To observe the files associated with this example, please select

Menu Project->Open- (from Demos) ->Cornering Stiffness Table Example

This example demonstrates the additional ability in msmac to change the cornering stiffness for the vehicle during the simulation. In this example, we compare the responses of two identical vehicles except for the fact that one of the vehicles has a air-out or blowout of the Right Rear tire during the simulation.

Cornering Stiffness Tables are input on cards 40 (vehicle 1) and/or cards 45 (vehicle 2).

Please note the following:

•    In the subject accident, the Static Margin is approximately 0.03 for the baseline vehicle. You can quickly observe the Static Margin in any msmac input file by select input card 6 or 7 and the Static Margin calculator pops up. Please see Static Margin for additional information.

•    In the subject example, at 0.9 seconds the cornering stiffness of the Right Rear tire of vehicle 2 is changed from 120 lbs/deg to 10 lbs/deg to reflect the changes in the cornering stiffness which occur during a tire blow out.

 

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Tire Friction Table Example