4569846498

Multibody systems simulation software 107
12000.0
FRONT DAMPER – SOLID, REAR DAMPER – DASH
9000.0
6000.0
Force (N)
3000.0
0.0
3000.0
6000.0
9000.0
5000.0 3000.0 1000.0 1000.0 3000.0 5000.0
6000.0 4000.0 2000.0 0.0 2000.0 4000.0 6000.0
Velocity (mm/s)
Fig. 3.30
Non-linear force characteristics for front and rear dampers
is described for use with tyre models. The format for this function expression
used here is
FUNCTION CUBSPL(x, z, id)
where
x the independent variable on the x-axis, in this case VR(1627,1728)
z is set to zero to indicate that the data set is two dimensional
id the id of the spline data set, in this case spline number 1
An example of the spline data set used here to represent the non-linear
damper force follows. In this case the velocities are defined in mm/s on the
x-axis and the values of force (N) are returned on the y-axis. It is important
that the data set has sufficient range at both the top and bottom end to
encompass the conditions during the simulation. Should the independent
variable used on the x-axis reach values outside of the range of the spline
data then the program will have to extrapolate values that can lead to unreliable
results.
SPLINE/1
,X 5000, 3150, 2870, 2450, 2205, 1925, 1610, 1260
,910, 630, 470, 400, 350, 300, 250, 230, 200, 190
,160, 120, 80, 55, 40, 20, 10, 1, 0.1, 0, 0.3, 3, 30, 40,
60,80, 100, 200, 250, 400, 490, 770, 1050, 1330, 1820, 2060, 2485, 2590
,2730, 2835, 2940, 3080, 5000
,Y 10 425, 5800, 5200, 4400, 4000, 3600, 3200, 2800, 2400, 2000, 1800
,1700, 1600, 1500, 1400, 1350, 1310, 1290, 1200, 1000, 700, 400, 210, 80
,40, 4, 0.4, 0, 1, 10, 100, 123, 150, 182, 200, 260, 300
,400, 500, 800, 1200, 1600, 2400, 2800, 3400, 3500
,3600, 3700, 3800, 4000, 7840
Although the method of modelling a non-linear force element has been
demonstrated here using a damper the method is equally applicable to other