PROFESSIONAL MOTORSPORT

SIMULATION SOFTWARE

Mono-, normal or triple spring configuration

Printscreen of the LapSim GUI where one can choose between a Mono-, normal- or triple-spring setup

With the three pushbuttons in the middle of the GUI one can select the desired configuration for the current axle.

In case of a triple spring configuration, the spring figure of the respective axle is split in two figures, as can be seen in the figure below.

Printscreen of the LapSim GUI where the four spring characteristics are plotted

Select in figure

To shift between the different springs, just click in the respective figure in the plot, which will subsequently highlight.

Or push the button in the middle of the figure which indicates which spring is the current one, to be edited.

Figure showing part of the spring characteristic without a helper spring

Spring rate, length and block-length

In the spring menu, the complete spring characteristic is specified, starting with the main spring, with its spring stiffness and unloaded length.

If the spring stiffness of the helper spring is set at zero, the other input boxes of the helper spring will disappear and LapSim assumes there is only a main spring.

Figure showing part of the spring characteristic where the helper spring is active

Adding a helper spring

In addition to the main spring, one can specify a helper spring, which goes on block at a certain compression force.

The example shows the result when a very light helper spring, just to keep the main spring in place, is added to the spring characteristic of the top figure. Within the graph it is shown when the helper goes on block.

Printscreen of the LapSim GUI showing the calculated spring platform distance based on spring lengths

Rebound and bump travel

Given the length of the main and helper spring, LapSim automatically calculates the spring platform distance in order to reach the bump and rebound travel specified in the last column.

In case of a triple spring configuration, the setup is over defined. By changing the rebound travel of the springs on can put more or less emphasis on the corner spring or one the third spring.

Anti Roll Bar stiffness in [N/mm] or [Nm/deg]

Printscreen of the LapSim GUI where one specifies the spring ratio and anti roll bar stiffness

In the last column of the LapSim GUI, the wheel to spring ratio is specified. A value smaller than 1 means, the spring travels less than the suspension.

The stiffness of the bar is specified at the wheel in order to compare with the stiffness of the main spring. Or it can be specified in Nm per degree body roll.

Linear or progressive characterisic

Printscreen of the LapSim GUI where one specifies the bumpstop and rebound limiter stiffness

Similar like the main and helper spring, in the first column the stiffness of the limiters are specified, whereas the first value represents the stiffness at the starting point, the second value the stiffness at the end of the suspension travel. The stiffness increases linear between these two points.

In the second column the distance is specified where the limiter will start before the end of the suspension travel.