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Modelling and analysis of suspension systems 181
Fig. 4.44 Vehicle durability testing on cobbled road surface (provided courtesy
of Jaguar Cars Ltd)
Table 4.8
Typical suspension loadcases
Loadcase Fx(N) Fy(N) Fz(N)
3g bump 11 180
2g rebound 7 460
0.75g cornering (outer wheel) 4 290 5 880
0.75g cornering (inner wheel) 1 180 1 620
1g braking 5 530 5 530
0.35g reverse braking 2 150 3 330
Kerb impact 9 270 4 120
Pothole braking 15 900 12 360
procedures but typically these will involve establishing road loads resulting,
for example, from accelerating, braking, cornering, striking potholes
and driving on rough surfaces such as that shown in Figure 4.44.
The loads that are applied to the suspension may be considered to act at the
tyre contact patch or at the wheel centre depending on the type of loadcase.
The loads shown in Table 4.8 are typical of those that might be used for a static
analysis on a vehicle of the type for which data is provided in this textbook. In
this example, the loads are defined in the x, y and z directions for a co-ordinate
system located at the centre of the tyre contact patch as shown in Figure 4.45.
For the loads shown in Table 4.8 it is possible to calculate values for cases
such as cornering and braking using traditional vehicle dynamics and the
principles of weight transfer. For cases involving impacts with kerbs and
bumps it may be necessary to obtain instrumented road load measurements
on the proving ground. A particularly severe case involves braking while