The tire models can be very sensitive to ground height. A CONSUB routine has been written which will adjust the height of the ground marker(s) to make sure that the vehicle's tires are in contact with the ground before any static simulation is performed. In addition, this routine can be accessed directly if the need arises, and it allows the user to specify which tire(s) to monitor and the minimum vertical force allowed at the tire.
The CONSUB can be invoked in the ground marker height adjustment mode by typing the following at the Adams prompt:
CONTROL/FUN=USER (1109,ftarget,itire,igrnd,ifothers)
where:
ftarget | = | (Optional) desired vertical force on the specified tire(s) (default is 1000) |
itire | = | (Optional) id of tire to use for vertical force calculation (default is 1) |
igrnd | = | (Optional) ground vertical distance marker (default is 3) |
ifothers | = | (Optional) value other than 0 indicates that all tires should be evaluated for ftarget |
For certain models such as K&C, in order to accurately represent the graphics when ground height is adjusted, PART/1 (Virtual ground) is connected to ground with a tranlational joint. The motion (MOTION/7777) on the joint is adjusted till the vehicle tires are in contact with the K&C posts.
For static tire models where the tire reaction forces act at different markers, the auto ground height adjuster will adjust all these markers untill the tire is in contact with ground.
Therefore the auto ground height adjuster routine, first searches for the presence of MOTION/7777 and adjusts the dispalcement of the motion. IF MOTION/7777 is not present, then the tire reaction force markers are verified. If these markers are other than 3, the vertical location of these markers are modifed. Else the vertical location of MARKER/3 is modified.