The fixed body equilibrium solution should be employed when the user requires a static solution at zero vehicle forward speed. This condition arises in simulations such as aligning the suspension of a vehicle. In this scenario, the CONSUB will not apply the tire lateral forces and moments since the vehicle is assumed to be resting on friction-less plates. Adams Car automatically writes out a full vehicle model with JPRIMS attaching the body to ground. These JPRIMS constrain the sprung mass in lateral and longitudinal displacement as well as yaw.
The CONSUB can be invoked in the fixed body equilibrium mode by typing the following at the Adams prompt:
CONTROL/FUN=USER (1010,jpr_ary,halt)
jpr_ary | = | Id of array containing the necessary jprims, motions, sforce ids to perform the static equilibrium |
halt | = | (Optional) parameter to terminate or continue a simulation after a static failure.
1 - stop the simulation if static fails (default).
0 - continue the simulation if static fails. |
When the user enters this command and runs a fixed body equilibrium, the user code takes the following steps:
1. The velocity of every single rigid part is assumed to be zero.
2. The velocity of the tires are also assumed to be zero. As a consequence, the tire routines are not able to generate lateral or longitudinal force so only the JPRIMS make it possible for Adams to reach static equilibrium.
3. The auxiliary column joint, MOTION/740, is set to zero.
If a dynamic analysis is requested in Adams after a fixed body equilibrium and the vehicle has velocity initial conditions, an initial transient effect will happen for the same reasons described above.