Simcenter 3D Tire Modelling

Accurate prediction of tire-road interactions for CAE-based driving dynamics assessment



Tire formulations


Simcenter 3D Motion Standard Tire includes three tire formulations: the non-inertial tire model, the basic tire model and the motorcycle tire model.The non-inertial tire model provides the most concise description of the vehicle tire. This formulation ignores the rota-tional inertia of the wheel, so the body to which the tire is attached must be constrained to the chassis or master body to avoid rotation. Most typical tire properties such as the unloaded radius, road friction coefficient, radial stiffness (constant or nonlinear) and damping, rolling resistance, cornering stiffness, and self- aligning moment arm must be defined. The model is valid for a limited range of applications only, such as agricultural tires.


The basic tire model enables you to improve accuracy by increasing the complexity of the force formulation:


  • All rotational degrees of freedom of the wheel are considered
  • Longitudinal forces due to the rolling slip can be simulated
  • Additional nonlinear properties can be specified, such as cornering stiff-ness based on tire vertical forces (“carpet plot” properties) and hysteresis on vertical loads
  • Roll, self-aligning and overturning moments calculation from these three force components
  • Scalable complexity of surface types for longitudinal slip force calculation
  • Coupling between longitudinal and lateral loads is supported through the “friction ellipse” approach. This takes into account the mutual limits to force components calculated as a function of friction coefficients and tire vertical force
  • Tire carcass effects can be included for high-frequency analyses
  • Different resolutions of the tire patch can be considered for a distributed contact normal force model (required for higher accuracy when road pro-files contain abrupt changes)
  • Support of the third-party tire formulation COSIN FTire (requiring an additional license from COSIN) for accurate prediction of ride comfort behavior and durability loads in full vehicle maneuvers




Road modeling

Simcenter 3D Motion Standard Tire sup-ports the following road modeling capabilities:


  • Scalable complexity of road profile definition, from a simple 2D representation (vertical height in function of the longitudinal distance) to a full 3D complex surface
  • Moving bodies are supported as road elements, and can be in contact with the tire, for moving road applications such as rotating drum test benches
  • Separate road friction coefficients for each tire in the model can be speci-fied to perform specific analyses, such as mu-split braking


Postprocessing


Predefined result sets are available as standard output, such as tire forces and moments, wheel position and orientation:


  • Reaction force and torque components on tire from chassis, tire, ground reference frame
  • Forces in the tire patch: vertical, longitudinal, lateral
  • Tire vertical deflection
  • Steer angle
  • Steer slip angle
  • Camber angle
  • Rolling slip
  • Rolling resistance
  • Friction force
  • Normal force unit vectors in the road coordinate system
  • Velocities at the tire patch: vertical, longitudinal, lateral
  • User-defined values


Support

Simofis Engineering and Siemens provides supports for training and consultancy.