Methods to Apply Kinematic Conditions

Numerical methods available in Radioss to apply the kinematic conditions are:

Penalty Method (Rigid Walls)

The node displacements are constrained by the application of penalty forces.

Main Secondary Kinematic Condition (Interface TYPE2 and Rigid Body)

All secondary nodes lose their independence. The degrees of freedom of the secondary nodes are expressed as a function of a main node or element.

Local Kinematic Condition (Rigid Link and Cylindrical Joint)

Constraint equations are applied to the nodes to satisfy local kinematic conditions. No main node is used.

Lagrange Multiplier (Radioss V44)

This method consists in the nonlinear resolution of the equilibrium equations under constraints. This method is optional for some classical kinematic conditions as: interfaces, rigid wall, rigid body and boundary conditions. It is a unique method that is available for some new kinematic conditions, such as: gear joints and interface TYPE16 and TYPE17.

This method is generally used when other methods are not applicable. For example, when the kinematic condition must be satisfied exactly while a node contacts a surface. On the other hand, as the method is based in the nonlinear resolution of equations by Newton-Raphson method, its efficiency may be poor for a general case.