-
Using the 521-Tire Model
About 521-TireThe 521-Tire model is a simple model that requires
a small set of parameters or experimental data to simulate the
behavior of tires. The 521-Tire is the first tire model
incorporated in Adams. The name 521 (actually 5.2.1) refers to the
version number of Adams/Tire when it was first released.
The slip forces and moments can be calculated in two ways:
Using the Equation method Using the Interpolation method
Two dedicated contact methods exist for the 521-Tire:
Point Follower, used for Handling analysis models Equivalent
Plane Method, used for 3D Contact analysis models
Any combination of force and contact method is allowed.
The road data files used for the 521-Tire are unique and cannot
be used in combination with any other Handling tire model. The 521
road file format is described in Road Data File
521_pnt_follow.rdf.
Note that the capability and generality of the 521-Tire have
been superseded by other, newer tire models, described throughout
this guide. Weve retained the 521-Tire model primarily for backward
compatibility. We recommend that you use other tire models for new
work.
-
Adams/Tire2
Using the 521-Tire Model
Tire Slip Quantities and Transient Tire Behaviour
Definition of Tire Slip QuantitiesSlip Quantities at Combined
Cornering and Braking/Traction
The longitudinal slip velocity Vsx in the SAE-axis system is
defined using the longitudinal speed Vx, the wheel rotational
velocity and the loaded rolling radius Rl:
The lateral slip velocity is equal to the lateral speed in the
contact point with respect to the road plane:
The practical slip quantities (longitudinal slip) and (slip
angle) are calculated with these slip velocities in the contact
point:
Note that for realistic tire forces the slip angle is limited to
90 degrees and the longitudinal slip in between -1 (locked wheel)
and 1.
Lagged longitudinal and lateral slip quantities (transient tire
behavior)In general, the tire rotational speed and lateral slip
will change continuously because of the changing interaction forces
in between the tire and the road. Often the tire dynamic response
will have an important role on the overall vehicle response. For
modeling this so-called transient tire behavior, a first-order
system is used both for the longitudinal slip as the side slip
angle, . Considering the tire belt as a
Vsx Vz R1=
Vsy Vy=
VsxVx------- and tan VsyVx
--------= =
-
3
Using the 521-Tire Model
stretched string, which is supported to the rim with lateral
springs, the lateral deflection of the belt can be estimated (see
also reference [1]). The figure below shows a top-view of the
string model.
Stretched String Model for Transient Tire Behavior
When rolling, the first point having contact with the road
adheres to the road (no sliding assumed). Therefore, a lateral
deflection of the string will arise that depends on the slip angle
size and the history of the lateral deflection of previous points
having contact with the road.
For calculating the lateral deflection v1 of the string in the
first point of contact with the road, the following differential
equation is valid during braking slip:
with the relaxation length in the lateral direction. The
turnslip can be neglected at radii larger than 10 m. This
differential equation cannot be used at zero speed, but when
multiplying with Vx, the equation can be transformed to:
When the tire is rolling, the lateral deflection depends on the
lateral slip speed; at standstill, the deflection depends on the
relaxation length, which is a measure for the lateral stiffness of
the tire. Therefore, with this approach, the tire is responding to
a slip speed when rolling and behaving like a spring at
standstill.
1Vx-----
dv1dt
--------v1------+ tan a+=
dv1dt
-------- Vx v1+ Vsx=A similar approach yields the following for
the deflection of the string in longitudinal direction:
-
Adams/Tire4
Using the 521-Tire Model
Now the practical slip quantities, and are defined based on the
tire deformation:
These practical slip quantities and are used instead of the
usual and definitions for steady-state tire behavior.
The longitudinal and lateral relaxation length are read from the
tire property file, see Tire Property File 521_equation.tir and
521_interpol.tir
Force CalculationsYou can use the 521-Tire model for handling
and durability analyses.
Directional Vectors for the Application of Tire Forces and
Torques at the Center of the Tire-Road Surface Contact Patch
du1dt
-------- Vx u1+ Vsx=
' u1------ Vx sin=
' v1------ atan=
-
5
Using the 521-Tire Model
The forces act along the directional vectors. From the tire spin
vector and various information you supply in the tire property and
the road profile data files, Adams/Tire determines the positions
and orientations of the tire vertical, lateral, and longitudinal
directional vectors. Figure 3 shows these directional vectors.
The tire vertical force acts along the vertical directional
vector, the tire aligning torque acts about the same vector, the
tire lateral force acts along the lateral directional vector, and
the tire longitudinal force acts along the longitudinal directional
vector. At this point, Adams/Tire determines the force directions
as if it were going to apply the tire aligning torque and all of
the tire forces at the center of the tire-road surface contact
patch.
The tire-road surface contact patch may deflect laterally.
Adams/Tire calculates the lateral deflection in the direction (and
with the sign) of the lateral force. The magnitude of the
deflection is equal to the lateral force divided by the tire
lateral stiffness you provide in the tire property data file.
The tire vertical, lateral, and longitudinal forces are forces
in the tire vertical, lateral, and longitudinal directions (as
determined at the tire-road surface contact patch). The tire
aligning torque is a torque about the tire vertical vector. The
vehicle durability force has components in both the tire vertical
and the tire longitudinal directions.
Normal ForceThe tire normal force Fz is calculated based on the
tire deflection and radial velocity. A progressive spring and
linear damping constant are employed:
where Fstiff is tire stiffness force and Fdamp is tire damping
force. The vertical stiffness force is calculated from:
where Kz is the tire vertical stiffness, is tire deflection, and
is the stiffness exponent. The tire damping force is calculated
from:
where Cz is the tire damping constant.
The damping constant is reduced for small tire deflections,
which are below 5% of the unloaded tire radius.
The tire vertical stiffness can also be described using a spline
function (force versus deflection) in the Adams dataset. The user
array is used to switch between tire property file stiffness and
spline stiffness. If the first value in the user array is equal to
'5215', the spline vertical stiffness is used. The second value of
the user array refers to the ID of the spline. The message, 'Using
spline data for the vertical spring', is shown in the message file.
If the first value in the user array is not equal to '5215', the
tire property file
Fz Fstiff Fdamp=
Fstiff Kz=
Fdamp Cz RadialVelocity=stiffness is used.
-
Adams/Tire6
Using the 521-Tire Model
The following is an example of using the spline vertical
stiffness:
! adams_view_name='spline_vertical_stiffness'SPLINE/10, X =
-1,0,10,30, Y = 0,0,2000,6000!!
adams_view_name='wheel_user_array'ARRAY/102, NUM=5215,10Another
option for having a non-linear tire stiffness is to introduce a
deflection-load table in the tire property file in a section called
[DEFLECTION_LOAD_CURVE]. See 521-Tire Tire and Road Property Files
on page 20. If a section called [DEFLECTION_LOAD_CURVE] exists, the
load deflection datapoints with a cubic spline for inter- and
extrapolation are used for the calculation of the vertical force of
the tire.
Longitudinal ForceThe tire longitudinal force Fx can have up to
three contributions:
Traction/braking force Rolling resistance force Durability force
(in case of durability contact)
Traction/Braking ForceTraction force is developed if the vehicle
is starting to move and a braking force if the vehicle is beginning
to stop. In either case, the absolute magnitude of the force is
calculated from:
where the friction coefficient is a function of the longitudinal
slip velocity Vsx in the contact patch. Note that this is somewhat
unusual, since all the other Handling tire models in Adams/Tire
assume that the longitudinal force Fx is a function of the slip
ratio.
Fx Fz=
-
7
Using the 521-Tire Model
Schematic of Friction Coefficient Versus Local Slip Velocity
The curve as a function of longitudinal slip velocity is created
using standard Adams STEP functions (see body 4 on page 10). You
have to specify two points on the curve to define this
characteristic:
The coordinates of the curve at static: (velocity static,
static) The coordinates of the curve at dynamic: (velocity dynamic,
dynamic)
The friction values may be available to you as function of slip
ratio instead of slip velocity. Converting Slip Ratio Data to
Velocity Data on page 16 explains how the slip ratios can be
converted to slip velocities.
Rolling Resistance ForceRolling resistance Moment My is
calculated from:
where coefrr is the rolling resistance coefficient that should
be supplied in the tire property data file.
Durability ForceDurability force, sometimes known as radial
planar force, is a special kind of tire vertical force. It is the
durability force that resists the action of road bumps. This force
acts along the instantaneous vertical directional vector calculated
by Adams/Tire. The Adams/Tire durability tire forces are limited to
two-
My coefrr Fz=dimensional forces that lie in the plane of the
tire and are directed toward the wheel-center marker.
-
Adams/Tire8
Using the 521-Tire Model
Adams/Tire superimposes these forces upon any traction or
lateral forces developed in the tire-road surface interaction.
You must select the Equivalent Plane Method for generating these
durability forces.
Lateral Force and Aligning TorqueTwo methods exist for
calculating the lateral force Fy and self-aligning moment Mz:
Interpolation Method Equation Method
Interpolation MethodThe AKIMA spline is employed to calculate Fy
and Mz as a function of the slip angle , camber angle , and
vertical load Fz. You should provide the data in the SAE axis
system.
Note that the slip angle and vertical load Fz input for the
force and moment calculation of Fx, Fy, Mx, My, and Mz are limited
to minimum and maximum values in the input to avoid unrealistic
extrapolated values.
Equation MethodThe Equation Method uses the following equation
to generate the lateral force Fy:
where K denotes the tire cornering stiffness coefficient.
The aligning moment Mz is calculated using the pneumatic trail t
according to:
while the pneumatic trails are calculated with half the contact
length a:
with R0 and Rl are, respectively, the unloaded and loaded tire
radius.
Overturning MomentIn both methods, the overturning moment Mx
calculation is based on the lateral tire force Fy, the lateral
Fy statFz 1 e K sign =
Mz t Fy=
t 13--- a e
K =
a R02 R1
2=tire stiffness Ky, and the vertical load:
-
9
Using the 521-Tire Model
Tire Lateral Force as a Function of Slip Angle
The contribution of the camber is disregarded in the Equation
Method.
The cornering stiffness equals .
Combined Slip of 5.2.1The combined slip calculation of the
5.2.1. is using the friction ellipse and is similar to the combined
slip calculation of the Pacejka '89 and '94 tire models.
Inputs:
Dimensionless longitudinal slip (range -1 to 1) and side slip
angle in radians
Longitudinal force Fx and lateral force Fy calculated using the
equations of 521-Tire
The vertical shift of Fy,a=0 is Fy calculated at zero slip
angle
Output:
Adjusted longitudinal force Fx and lateral force Fy incorporates
the reduction due to combined slip:
MxFyKy------= Fz
statFzKa
kk2 2sin+
-----------------------------
acos=Friction coefficients:
-
Adams/Tire10
Using the 521-Tire Model
Forces corrected for combined slip conditions:
Due to the lateral deflection of the tire patch, the aligning
moment under combined slip conditions increases by the effect of
the longitudinal force Fx and the lateral tire stiffness Ky:
and the overturning moment uses the lateral force for combined
slip:
SmoothingWhen you indicate smoothing by setting the value of
USE_MODE in the tire property file, Adams/Tire smooths initial
transients in the tire force over the first 0.1 seconds of the
simulation. The longitudinal force, lateral force, and aligning
torque are multiplied by a cubic step function of time. (See STEP
in the Adams/Solver online help.)
Longitudinal Force Fx = SFx Lateral Force Fy = SFy Overturning
moment torque Mx = SMz Aligning torque Mz = SMz
Changing the Operating Mode: USE_MODEYou can change the behavior
of the tire model by changing the value of USE_MODE in the [MODEL]
section of the tire property file. If USE_MODE equals zero, or when
it is absent, the smoothing time
x actFxFz-----= y act
Fy Fy 0=Fz
------------------------------=
x 11x act-------------
2 tanstat-----------
2+
----------------------------------------------------= y
tan1stat----------
2 tany act-------------
2+
---------------------------------------------------=
Fx combx
x act-------------Fx= Fy comb
yy act------------- Fy Fy 0=+ =
Mz comb Mz pure Fx comb+=Fy comb
Ky------------------
Mx combFy comb
Ky------------------Fz=
-
11
Using the 521-Tire Model
equals 0.001 seconds and the 521-Tire model is compatible with
the previous Adams/Solver implementation.
By selecting a value of USE_MODE between 1 and 4, smoothing and
combined slip correction can be switched on and off, as shown in
Table 1. The smoothing time equals 0.1 seconds for these values of
USE-MODE.
Converting Slip Ratio Data to Velocity DataAdams/Tire requires
that you enter the velocities that correspond to static and
dynamic. You will often obtain this information as the coefficient
of friction versus slip ratio. You can calculate the velocities
required by Adams/Tire from the coefficient of friction versus slip
ratio curve in the following way:
where
= Slip ratio
= Free rolling rotational velocity (no slip)
= Actual rotational velocity
Kinematic relationships between translational and rotational
velocities and the effective rolling radius give:
where
= Contact patch velocity reletive to road surface
USE_MODE: Smoothing: Combined slip correction:1 off off2 off on3
on off4 on on
a ff------------------=
fa
aVx Vsx
Re-------------------=
fVxRe-----=
Vsx
-
Adams/Tire12
Using the 521-Tire Model
= Actual longitudinal velocity
= Effective rolling radius
Substituting these relationships into the original slip ratio
equation with some cancelling of variables gives:
Therefore:
During testing for the coefficient of friction as a function of
slip ratio, the longitudinal velocity Vx is held constant.
Therefore, you can obtain Vsx, the relative velocity of the contact
patch with respect to the road surface, from the test data curves
for the static and dynamic values of friction.
Contact MethodsFor handling analyses (which use a flat road
surface profile), the 521-Tire model uses the point-follower
contact method. For durability analyses (which use uneven road
surface profiles), the Equivalent Plane Method yields the
instantaneous tire radius directly, while finding the new road
surface orientation vector.
About the Point-Follower MethodThe point-follower contact method
assumes a single contact point between the tire and road. The
contact point is the point nearest to the wheel center that lies on
the line formed by the intersection of the tire (wheel) plane with
the local road plane.
The contact force computed by the point-follower contact method
is normal to the road plane. Therefore, in a simulation of a tire
hitting a pothole, the point-follower contact method does not
generate the expected longitudinal force.
About the Equivalent Plane Method 521-Tire uses the Equivalent
Plane method to reorient the vertical road surface vector, which
gives the direction of the vertical force, and to calculate the new
tire radius. To do this, a new smooth road surface is generated at
an angle calculated such that only the shape of the tire is
different (see body 6 on page 18).
Equivalent Plane Method
Vx
Re
VsxVx-------=
Vsx Vx=
-
13
Using the 521-Tire Model
Both the deflected tire area and its centroid remain unchanged.
The vector between the deflected area centroid and the wheel-center
marker then determines the orientation of the. vertical vector
perpendicular to the road surface.
The Equivalent Plane method is best suited for relatively large
obstacles because it assumes the tire encompasses the obstacle
uniformly. In reality, the pneumatics and the bending stiffness of
the tire carcass prevent this. The result is an uneven pressure
distribution and possibly gaps between the tire and the road. If
the obstacle is larger than the tire contact patch (such as a
pothole or curb), the uniform assumption is good. If the obstacle
is much smaller than the tire patch, however (such as a tar strip
or expansion joint), the assumption is poor, and the Equivalent
Plane method may greatly underestimate the durability force.
Definition of Equivalent Plane Parameters
-
Adams/Tire14
Using the 521-Tire Model
When using the Equivalent Plane method the following parameters
need to be specified in the tire property file:
Equivalent_plane_angleSpecifies the subtended angle (in degrees)
bisected by the z-axis of the wheel-center marker, as shown in
Figure 7. This angle determines the extent of the road the tire can
envelop. The value of the equivalent_plane_angle must be between 0
and 180 degrees.
Equivalent_plane_incrementsSpecifies the number of increments
into which the shadow of the tire subtended section is divided, as
shown in Figure 7.
521-Tire Tire and Road Property FilesThis section contains four
example input data files. For reference, the files are called:
521_equation.tir 521_interpol.tir 521_pnt_follow.rdf
521_equiv_plane.rdf
The first two files are tire property files, and the last two
are road files. The file 521_equation.tir illustrates the required
format and parameters when you use the Equation method. The file
521_interpol.tir illustrates the Interpolation method. The two
*.rdf files show how road data files must be specified when either
of the contact methods is used.
Tire Property File 521_equation.tir and 521_interpol.tirYou can
select the method for calculating the normal force by setting the
VERTICAL_FORCE_METHOD parameter to either POINT_FOLLOWER (for the
Point Follower method) or EQUIVALENT_PLANE (for the Equivalent
Plane method). See Contact Methods on page 17 for details on these
methods.
You can select the method for calculating the lateral force by
setting the LATERAL_FORCE_METHOD parameter to either INTERPOLATION
or symbol. See Lateral Force and Aligning Torque on page 11 for
details on these calculation methods.
The following table specifies how some of the parameter names
used in the tire property file correspond to parameters introduced
in the equations that were presented in the previous sections.
Parameter in file: Used in equation: As
parameter:vertical_stiffness [10] Kzvertical_damping [11] Cz
lateral_stiffness [18] Ky
-
15
Using the 521-Tire Model
521-equation.tirThe 521-equation.tir example tire property file
starts here.
$----------------------------------------------------------MDI_HEADER[MDI_HEADER]
FILE_TYPE = 'tir' FILE_VERSION = 3.0 FILE_FORMAT =
'ASCII'(COMMENTS){comment_string}'Tire - XXXXXX''Pressure -
XXXXXX''Test Date - XXXXXX''Test
tire'$---------------------------------------------------------------units[UNITS]
LENGTH = 'mm' FORCE = 'newton' ANGLE = 'rad' MASS = 'kg' TIME =
'second'$---------------------------------------------------------------model[MODEL]!
use mode 1 2 3 4 11 12 13 14!
------------------------------------------------------------------!
smoothing X X X X! combined X X X X! transient X X X X!
PROPERTY_FILE_FORMAT = '5.2.1' USE_MODE =
1$-----------------------------------------------------------dimension[DIMENSION]
cornering_stiffness_coefficient [6] KMu_Static Figure 4
staticMu_Dynamic Figure 4 dynamicMu_Static_velocity Figure 4
velocity staticMu_Dynamic_Velocity Figure 4 velocity
dynamicrolling_resistance_coefficient [13]
coeffrrvertical_stiffness_exponent [141] Note: If you do not
specify
vertical_stiffness_exponent in the tire property file, 521-Tire
uses the default value of 1.1.
Parameter in file: Used in equation: As parameter:
UNLOADED_RADIUS = 310.0
-
Adams/Tire16
Using the 521-Tire Model
WIDTH = 195.0 ASPECT_RATIO = 0.70 RIM_RADIUS = 195,0 RIM_WIDTH =
139.7$----------------------------------------------------------parameters!
VERTICAL_FORCE_METHOD = EQUIVALENT_PLANE LATERAL_FORCE_METHOD =
EQUATION! vertical_stiffness = 206.0 vertical_stiffness_exponent =
1.1 vertical_damping = 2.06! lateral_stiffness = 50
cornering_stiffness_coefficient = 50! Mu_Static = 0.95 Mu_Dynamic =
0.75 Mu_Static_Velocity = 3000 Mu_Dynamic_Velocity = 6000!
rolling_resistance_coefficient = 0.01! EQUIVALENT_PLANE_ANGLE= 100
EQUIVALENT_PLANE_INCREMENTS= 50!
521_interpol.tirThe 521-interpol.tir example tire property file
starts here. In addition to the file for 521_equation.tir, it
contains data that is used for calculating the lateral force and
aligning moment, instead of using formula 6 to 9. Note that the
[DEFLECTION_LOAD_CURVE] can also be used in the tire property file
for the Equation method.
$----------------------------------------------------------MDI_HEADER[MDI_HEADER]
FILE_TYPE = 'tir' FILE_VERSION = 3.0 FILE_FORMAT =
'ASCII'(COMMENTS){comment_string}'Tire - XXXXXX''Pressure -
XXXXXX''Test Date - XXXXXX''Test
tire'$---------------------------------------------------------------units[UNITS]
LENGTH = 'mm' FORCE = 'newton' ANGLE = 'rad' MASS = 'kg'
TIME =
'second'$---------------------------------------------------------------model
-
17
Using the 521-Tire Model
[MODEL]! use mode 1 2 3 4 11 12 13 14!
----------------------------------------------------------------!
smoothing X X X X! combined X X X X! transient X X X X!
PROPERTY_FILE_FORMAT = '5.2.1' USE_MODE =
1$-----------------------------------------------------------dimension[DIMENSION]
UNLOADED_RADIUS = 310.0 WIDTH = 195.0 ASPECT_RATIO = 0.70
RIM_RADIUS = 195,0 RIM_WIDTH =
139.7$----------------------------------------------------------parameters!
VERTICAL_FORCE_METHOD = POINT_FOLLOWER ! or EQUIVALENT_PLANE
LATERAL_FORCE_METHOD = INTERPOLATION ! or EQUATION!
vertical_stiffness = 206.0 vertical_stiffness_exponent = 1.1
vertical_damping = 2.06 lateral_stiffness = 50
cornering_stiffness_coefficient = 50! Mu_Static = 0.95 Mu_Dynamic =
0.75 Mu_Static_Velocity = 3000 Mu_Dynamic_Velocity = 6000!
rolling_resistance_coefficient = 0.01! EQUIVALENT_PLANE_ANGLE= 100
EQUIVALENT_PLANE_INCREMENTS= 50!!------------------CAMBER ANGLE
VALUES-------------------------------! Conversion! No. of pnts
factor(D to R) pnt1 pnt2 pnt3 pnt4 pnt5! CAMBER_ANGLE_DATA_LIST 5
0.017453292 -3.0 0.0 3.0 6.0 10.0!!------------------SLIP ANGLE
VALUES---------------------------------! Conversion! No. of pnts
factor(D to R) pnt1 ...... pnt9! SLIP_ANGLE_DATA_LIST 9 0.017453292
-15.0 -10.0 -5.0 -2.5 0.0 2.5 5.0 10.0 15.0!
!-----------------VERTICAL FORCE
VALUES------------------------------
-
Adams/Tire18
Using the 521-Tire Model
! Conversion ! No. of pnts factor! pnt1 pnt2 pnt3 pnt4 pnt5 !
VERTICAL_FORCE_DATA_LIST 5 4.448 200.0 600.0 1100.0 1500.0
1900.0!!-----------------ALLIGNING TORQUE
VALUES---------------------------! No. of pnts Conversion! factor!!
pnt1 .... pnt225! ALIGNING_TORQUE_DATA_LIST 225 -1355.7504 5.31
6.52 22.88 26.41 30.58 0.11 2.84 5.49 -3.92 -14.04 0.47 -12.44
-37.99 -67.22 -116.07 0.04 -21.38 -69.04 -111.44 -168.11 0.80 -3.70
-27.94 -44.25 -53.74 1.75 17.43 52.20 81.97 145.78 2.54 11.08 40.53
73.54 95.55 -1.28 0.02 14.82 2.93 10.35 1.59 -3.77 -17.17 6.60
-11.91 0.06 14.23 22.93 11.45 15.74 5.95 5.54 13.72 -1.65 -15.64
-1.29 -9.45 -26.98 -57.25 -107.71 -5.05 -17.73 -62.62 -109.03
-161.88 0.46 -2.48 -19.48 -33.54 -49.52 4.71 26.10 60.80 90.85
119.51 4.26 16.60 52.46 93.32 141.34 2.41 4.28 2.21 9.11 30.44
-0.92 0.22 12.61 2.51 -18.77 0.43 -4.62 15.36 7.16 11.70 6.70 15.92
0.14 -4.20 -11.81 -2.20 -5.53 -13.28 -47.48 -92.88 -1.39 -17.28
-52.17 -102.80 -161.71 2.87 -0.38 -14.27 -29.03 -42.42 6.99 24.54
66.06 93.27 126.38 7.10 18.78 58.20 104.51 156.39 1.63 2.91 8.33
20.32 42.09 -0.78 10.13 -9.94 -13.02 -11.95 5.62 4.36 23.16 38.03
8.73 2.31 6.41 14.10 6.03 -11.66 7.87 1.33 -16.31 -40.24 -82.58
1.40 -10.04 -50.94 -93.06 -157.50 2.10 0.56 -16.15 -27.15 -40.13
5.60 26.48 62.92 90.16 122.03
3.56 20.63 60.74 108.26 162.97
-
19
Using the 521-Tire Model
-0.08 1.81 14.39 34.98 59.72 1.38 -2.13 -2.42 -4.08 -2.72 3.69
1.71 29.06 10.05 11.38 3.09 7.15 -7.92 13.53 -5.78 6.08 0.38 -2.69
-32.10 -62.17 0.76 -7.65 -37.28 -89.05 -145.09 0.70 4.37 -7.59
-23.71 -28.49 5.92 34.39 72.55 92.88 129.34 4.36 29.81 76.70 118.91
180.59 -2.03 5.94 26.18 53.59 89.76 0.39 -5.52 -6.06 10.16 7.81
!-----------------LATERAL FORCE
VALUES------------------------------ ! No. of pnt Conversion !
factor ! pnt1 .... pnt225 ! LATERAL_FORCE_DATA_LIST 225 4.448
234.08 585.56 1000.29 1307.77 1603.78 269.79 628.82 1040.78 1331.72
1624.83 213.70 565.29 974.49 1198.82 1387.74 150.79 452.18 752.21
885.23 960.13 11.52 50.58 199.87 199.50 208.75 -116.75 -367.42
-618.68 -683.16 -857.81 -224.15 -588.24 -1001.01 -1235.88 -1488.88
-242.08 -612.70 -1059.55 -1344.53 -1658.66 -213.99 -597.29 -988.14
-1343.86 -1689.35 234.40 572.75 981.30 1352.37 1698.90 239.27
647.77 1007.37 1357.22 1666.30 252.34 603.75 1033.50 1288.76
1483.64 167.55 481.45 826.41 962.64 1028.74 32.23 78.77 231.31
250.14 254.32 -122.59 -423.13 -552.58 -613.52 -607.61 -208.93
-576.28 -948.45 -1149.44 -1314.69 -261.05 -634.90 -1064.15 -1338.52
-1581.84 -241.50 -607.16 -1021.87 -1322.30 -1598.25 210.20 578.56
968.72 1344.05 1730.40 237.91 600.60 1025.67 1377.57 1733.03 226.60
629.48 1084.97 1354.12 1575.22 154.74 496.21 878.72 1028.03 1095.59
34.37 74.19 240.00 284.42 283.85 -130.29 -339.00 -509.04 -543.75
-555.05 -226.48 -557.52 -884.91 -1083.18 -1175.12 -270.70 -595.22
-1059.76 -1314.74 -1564.43 -254.64 -602.76 -1032.71 -1313.22
-1609.96 238.28 531.25 945.70 1305.28 1786.96 227.13 594.51 1038.87
1365.33 1733.29 221.76 633.49 1135.31 1375.28 1619.82
195.50 505.90 899.88 1059.92 1135.28
-
Adams/Tire20
Using the 521-Tire Model
28.51 68.59 241.99 311.15 331.84 -145.10 -319.56 -464.11 -499.27
-500.83 -230.33 -548.99 -815.88 -991.78 -1108.36 -230.62 -597.10
-1009.76 -1261.43 -1504.09 -218.36 -570.13 -1049.72 -1344.94
-1589.60 228.49 564.69 954.06 1332.84 1687.50 221.19 595.52 1019.74
1378.35 1749.40 224.63 590.58 1108.01 1408.87 1707.09 178.96 474.70
918.87 1125.97 1242.75 42.58 65.26 230.69 306.58 428.45 -144.43
-290.91 -368.02 -398.98 -394.66 -224.99 -494.65 -761.78 -886.03
-941.20 -246.51 -563.13 -980.33 -1249.57 -1462.88 -239.34 -567.10
-1050.56 -1348.66 -1611.11
521-Tire Road Data FilesThe road data files used with the
521-Tire are unique and cannot be used with any other tire model.
The data files are fully described by the following two
examples.
Road Data File 521_pnt_follow.rdfThis example file shows that,
if you use the Point Follower method and indicate it in the
associated tire property file, the road_profile_type parameter must
be set to FLAT.
$--------------------------------------------------------MDI_HEADER[MDI_HEADER]FILE_TYPE
= 'rdf'FILE_VERSION = 5.00FILE_FORMAT =
'ASCII'(COMMENTS){comment_string}'flat 2d contact road for testing
purposes'$-------------------------------------------------------------UNITS[UNITS]
LENGTH = 'mm' FORCE = 'newton' ANGLE = 'radians' MASS = 'kg' TIME =
'sec'$-------------------------------------------------------------MODEL[MODEL]
METHOD = '5.2.1' FUNCTION_NAME =
'ARC913'$--------------------------------------------------------PARAMETERSROAD_PROFILE_TYPE
= FLATINITIAL_HEIGHT = 0.000
-
21
Using the 521-Tire Model
Road Data File 521_equiv_plane.rdfThe following example shows
which data the road data file must contain if the Equivalent Plane
method is used and specified in the associated tire property file.
The main difference with the road data file used in association
with the Point Follower method is that here the ROAD_PROFILE_TYPE
parameter is set to INPUT and a ROAD_INPUT_DATA_LIST is
specified.
$---------------------------------------------------------MDI_HEADER[MDI_HEADER]FILE_TYPE
= 'rdf'FILE_VERSION = 5.00FILE_FORMAT =
'ASCII'(COMMENTS){comment_string}'5.2.1 input road for testing
purposes'$--------------------------------------------------------------UNITS[UNITS]
LENGTH = 'mm' FORCE = 'newton' ANGLE = 'radians' MASS = 'kg' TIME =
'sec'$--------------------------------------------------------------MODEL[MODEL]
METHOD = '5.2.1' FUNCTION_NAME =
'ARC913'$---------------------------------------------------------PARAMETERSROAD_PROFILE_TYPE
= INPUTINITIAL_HEIGHT = 0.000ROAD_INPUT_DATA_LIST 23, 1 -10000.00,
00.00 1740.00, 00.00 1740.94, 1.92 1743.73, 3.55 1748.31, 4.59
1754.55, 4.79 1762.32, 3.88 1771.41, 1.65 1781.61, 7.89 1792.65,
2.47 1804.28, 5.26 1816.20, 6.20 1828.12, 5.26 1839.75, 2.47
1850.79, 7.89 1860.99, 1.65 1870.08, 3.88 1877.85, 4.79 1884.09,
4.59 1888.67, 3.55 1891.46, 1.92 1892.40, 00.00
40000.00, 00.00
-
Adams/Tire22
Using the 521-Tire Model
Using the 521-Tire ModelAbout 521-TireTire Slip Quantities and
Transient Tire BehaviourForce CalculationsCombined Slip of
5.2.1SmoothingChanging the Operating Mode: USE_MODEConverting Slip
Ratio Data to Velocity DataContact Methods521-Tire Tire and Road
Property Files