Challenge

Adams Assignments – Problem 5 – Compliance

SSrikanth Geesala14 Oct 2021

Rear multi link subsystem is opened from Acar shared, and then this saved as assembly in our private folder, and the same file is opened. and following simulation is carried out-

1. brake steer-
Brake steer= 0.06 deg/KN
Brake steer= 0.16 deg/mm
so the suspension toes out making the car oversteer.

2. Traction steer-

Traction steer => 0.016 deg/ mm

suspension toes out while braking, leading to oversteer.

3. Longitudnal wheel center recession under traction (mm/KN)
Longitudinal wheel center recession under traction= 0.692 mm/KN
Longitudinal wheel center recession under braking= 0.89 mm/KN

These two vary, since the braking force applied at contact patch and traction force is applied at wheel centre and the direction of the forces is opposite to each other.

4. Lateral force compliance steer (deg/KN)-

Lateral force compliance steer = 1.67*10^-4 deg/N

on increasing the lateral force, the wheel toe out . toe out in rear wheel results in oversteer.

5. Lateral force compliance camber -

Lfcc = 0.4 deg/KN
on increasing the lateral force, the wheel camber in negative. this gives understeer.

6. bump steer-
for bump steer we input the values for vertical length in static load suspension analysis.
Bump steer= 0.0015 deg/mm
from the graph given below we can see the wheel toes out during jounce, hence it is a over steer effect.

TUNING-

Parallel wheel travel analysis is carried out with initial/ original hardpoints, and then the hardpoints are changed accordingly as shown below, after plotting the graphs and comparing bump steer 2.6deg/m is achieved.. this is a over steer effect.