Static Steer Analysis

A quasi-static simulation during which a steering input is applied to the model and various parameters are calculated.

Required input

Vehicle parameters:
  • Tire static loaded radius (mm)
  • Tire vertical spring rate (N/mm)
  • Vehicle CG height (mm)
  • Wheel base (mm)
  • Front braking ratio
  • Front drive ratio
  • Axle ratio
  • Vehicle weight (N)
Suspension and steering travel:
  • Initial left wheel displacement (mm)
  • Initial right wheel displacement (mm)
  • Steering travel (mm/deg)

Task Description

An initial displacement is applied to the left and right suspension. This is followed by a steering movement during which a maximum positive and negative steering input is applied and various parameters are calculated.

Output

Reports containing some plots, tabular results, and graphical animation are automatically created.

The following parameters are calculated during the simulation and the results are written to a text file (sdf.out). The same results are also written into the request file as user requests.
Wheel Center Displacement
mm
Ground Reaction Force
N
Toe-in
deg
Steer Angle
deg
Camber Angle
deg
Caster
deg
Kingpin Inclination
deg
Scrub Radius
mm
Caster Trail
mm
Roll Angle
deg
Tread Width
mm
Tread Change
mm/m
Track Width
mm
Wheel Center X Stiffness
N/mm
Wheel Center Y Stiffness
N/mm
Wheel Center Z Stiffness
N/mm
Wheel Center XX Stiffness
N-m/deg
Wheel Center YY Stiffness
N-m/deg
Wheel Center ZZ Stiffness
N-m/deg
Parallel Lateral Force Deflection
mm/kN
Converging Lateral Force Deflection
mm/kN
Parallel Lateral Force Steer
deg/kN
Converging Lateral Force Steer
deg/kN
Parallel Lateral Force Camber
deg/kN
Converging Lateral Force Camber
deg/kN
Parallel Aligning Torque Steer
deg/100N-m
Converging Aligning Torque Steer
deg/100N-m
Longitudinal Force Deflection @ Wheel center
mm/kN
Longitudinal Force Deflection @ Tire patch
mm/kN
Longitudinal Compliance Steer @ Wheel center
deg/kN
Longitudinal Compliance Steer @ Tire patch
deg/kN
Longitudinal Caster Compliance @ Wheel center
deg/kN
Longitudinal Caster Compliance @ Tire patch
deg/kN
Side View Swing Arm Length
mm
Side View Swing Arm Angle
deg
Side View Swing Arm Fore/Aft Location
mm
Side View Swing Arm Vertical Location
mm
Front View Swing Arm Length
mm
Front View Swing Arm Angle
deg
Front View Swing Arm Lateral Location
mm
Front View Swing Arm Vertical Location
mm
Ride Steer
deg/m
Ride Caster
deg/m
Ride Camber
deg/m
Roll Steer
%
Roll Caster
%
Roll Camber
%
Roll Inclination
%
Wheel Rate
N/mm
Ride Rate
N/mm
Hop Rate
N/mm
Suspension Roll Rate
N-m/deg
Total Roll Rate
N-m/deg
Tramp Rate
N-m/deg
Roll Center Height
mm
Roll Center Lateral
mm
Anti-lift
%
Acceleration Lift
mm/g
Anti-dive
%
Brake Dive
mm/g
Tractive Force Steer
deg/g
Tractive Force Windup
deg/g
Brake Steer
deg/g
Spindle Length
mm
Spindle Offset
mm
Ideal Steer Angle
deg
Curb to Curb Diameter 1
m
% Ackerman 1
%
Ackerman Deviation 1
deg
Curb to Curb Diameter 2
m
% Ackerman 2
%
Ackerman Deviation 2
deg
% Ackerman 3
%
Curb to Curb Diameter 4
m
% Ackerman 4
%
Ackerman Deviation 4
deg
Required input
of task

Table 1.
Parameter Units
Wheel Center Displacement mm
Ground Reaction Force N
Toe-in deg
Steer Angle deg
Camber Angle deg
Caster deg
Kingpin Inclination deg
Scrub Radius mm
Caster Trail mm
Roll Angle deg
Tread Width mm
Tread Change mm/m
Track Width mm
Wheel Center X Stiffness N/mm
Wheel Center Y Stiffness N/mm
Wheel Center Z Stiffness N/mm
Wheel Center XX Stiffness N-m/deg
Wheel Center YY Stiffness N-m/deg
Wheel Center ZZ Stiffness N-m/deg
Parallel Lateral Force Deflection mm/kN
Converging Lateral Force Deflection mm/kN
Parallel Lateral Force Steer deg/kN
Converging Lateral Force Steer deg/kN
Parallel Lateral Force Camber deg/kN
Converging Lateral Force Camber deg/kN
Parallel Aligning Torque Steer deg/100N-m
Converging Aligning Torque Steer deg/100N-m
Longitudinal Force Deflection @ Wheel center mm/kN
Longitudinal Force Deflection @ Tire patch mm/kN
Longitudinal Compliance Steer @ Wheel center deg/kN
Longitudinal Compliance Steer @ Tire patch deg/kN
Longitudinal Caster Compliance @ Wheel center deg/kN
Longitudinal Caster Compliance @ Tire patch deg/kN
Side View Swing Arm Length mm
Side View Swing Arm Angle deg
Side View Swing Arm Fore/Aft Location mm
Side View Swing Arm Vertical Location mm
Front View Swing Arm Length mm
Front View Swing Arm Angle deg
Front View Swing Arm Lateral Location mm
Front View Swing Arm Vertical Location mm
Ride Steer deg/m
Ride Caster deg/m
Ride Camber deg/m
Roll Steer %
Roll Caster %
Roll Camber %
Roll Inclination %
Wheel Rate N/mm
Ride Rate N/mm
Hop Rate N/mm
Suspension Roll Rate N-m/deg
Total Roll Rate N-m/deg
Tramp Rate N-m/deg
Roll Center Height mm
Roll Center Lateral mm
Anti-lift %
Acceleration Lift mm/g
Anti-dive %
Brake Dive mm/g
Tractive Force Steer deg/g
Tractive Force Windup deg/g
Brake Steer deg/g
Spindle Length mm
Spindle Offset mm
Ideal Steer Angle deg
Curb to Curb Diameter 1 m
% Ackerman 1 %
Ackerman Deviation 1 deg
Curb to Curb Diameter 2 m
% Ackerman 2 %
Ackerman Deviation 2 deg
% Ackerman 3 %
Curb to Curb Diameter 4 m
% Ackerman 4 %
Ackerman Deviation 4 deg