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Tuesday November 21st 2017

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Relationship between the adhesion utilisation and the rate of braking

The adhesion utilizations, f, can be calculated using the equations:

adhesion_utilization_f_front_rear

 The loads applied (static load +/- transfer load) on the front (N1) and rear (N2) axles can be calculated using the following equations:

applied_loads_normal_load_weight_transferWhere:

P = Weight of car

Z = Rate of braking

h = Height of CG.

P1 = Front axle weight

P2 = Rear axle weight

E = Wheelbase

N1 = Front down force

N2 = Rear down force

 


Please see following figure. Rate of Braking, Z, is the level of deceleration in g. Adhesion Utilization is equivalent to the Coefficient of Friction. All wheels lock together at 0.821g.  Front  wheels lock first at a rate of braking smaller than 0.821g. Rear wheels lock for rates of braking higher than 0.821g.

adhesion_utilization_f_front_rear_lock_wheels_plot

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