MF-Tyre/MF-Swift Reduced Tire Input Properties

The use of reduced tire input properties in MF-Tyre/MF-Swift is possible when the available measurement data is limited. Built-in procedures are used to provide a reasonable estimate for the missing data and only require a small number of coefficients.

The following table gives the minimum required coefficients. This is reproduced from the SIEMENS MF-Tyre/MF-Swift User Manual.
Coefficient Description
FITTYP Magic Formula version number
UNLOADED_RADIUS Free tire radius
WIDTH Tire width
RIM_RADIUS Rim radius
INFLPRES* Tire inflation pressure
FNOMIN Nominal wheel load
VERTICAL_STIFFNESS* Tire vertical stiffness at nominal load and inflation pressure
PDX1* Longitudinal friction coefficient at nominal conditions**
PKX1* PKX1*FNOMIN is the longitudinal slip stiffness at the nominal wheel load
PDY1* Lateral friction coefficient at nominal conditions**
PKY1* PKY1*FNOMIN is the maximum value of the cornering stiffness versus vertical load characteristic
PKY2* PKY2*FNOMIN is the vertical load at which the cornering stiffness reaches its maximum value

* Highly recommended parameters (when not specified defaults are used).

** At nominal wheel load, nominal inflation pressure and zero camber angle.

Note: When using a reduced parameter file, detailed effects such as combined slip, tire relaxation effects and enveloping behavior on short wave road obstacles are included, even when the related parameters are not explicitly specified.

Example

The minimum required reduced tire parameters are highlighted in the following example. For detailed information, refer to SIEMENS MF-Tyre/MF-Swift User Manual.
[MDI_HEADER]
FILE_TYPE                ='tir'
FILE_VERSION             =3.0
FILE_FORMAT              ='ASCII'
! FILE_NAME :         TNO_car205_60R15.tir
$----------------------------------------------------------------units
[UNITS]
LENGTH                   ='meter'
FORCE                    ='newton'
ANGLE                    ='radians'
MASS                     ='kg'
TIME                     ='second'
$----------------------------------------------------------------model
[MODEL]
FITTYP                   = 62                $Magic Formula Version number             
TYRESIDE                 ='Left'
LONGVL                   = 16.7              $Nominal speed         
VXLOW                    = 1                 $Lower boundary of slip calculation      
ROAD_INCREMENT           = 0.01              $Increment in road sampling
ROAD_DIRECTION           = 1                 $Direction of traveled distance 
!
! USE_MODE specifies the type of calculation performed:
!       0: Fz only, no Magic Formula evaluation
!       1: Fx,My only
!       2: Fy,Mx,Mz only
!       3: Fx,Fy,Mx,My,Mz uncombined force/moment calculation
!       4: Fx,Fy,Mx,My,Mz combined force/moment calculation
!       5: Fx,Fy,Mx,My,Mz combined force/moment calculation + turnslip
!      +0: steady state behaviour
!     +10: including relaxation behavior
!     +20: including relaxation behavior (nonlinear)
!     +30: including rigid ring dynamics
!    +100: smooth road contact
!    +200: smooth road contact (circular cross section, motorcycles)
!    +400: road contact for 2D roads (using traveled distance)
!    +500: road contact for 3D roads
!
!  example: USE_MODE = 434 implies:
!    -combined slip 
!    -rigid ring dynamics
!    -road contact for 2D roads
PROPERTY_FILE_FORMAT     ='SWIFT-TYRE'
FUNCTION_NAME            = 'tnodelft::DTYRE'
N_TIRE_STATES            = 5
USE_MODE                 = 114               $Tyre use mode switch 
HMAX_LOCAL               = 2.5E-4            $Local integration time step (ADAMS only)
SWITCH_INTEG             = 0.1               $Overrule local integrator when set to 0 (ADAMS only)
$-----------------------------------------------------------dimensions
[DIMENSION]
UNLOADED_RADIUS          = 0.3135            $Free tyre radius         
WIDTH                    = 0.205             $Nominal section width of the tyre         
RIM_RADIUS               = 0.1905            $Nominal rim radius
$--------------------------------------------------------------inertia
[VERTICAL]
FNOMIN                   = 4000              $Nominal wheel load