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# SOL 112 Enforced Rotational Motion Load without restrictions to small rotations or to a fixed axis

Experimenter

Is it possible to apply a rotational motion by a set of several arbitrary matrices of rotation defining a sufficiently smooth change of a coordinate system in time using method SOL 112?

The application behind is the calculation of the deformation of a blank sheet (fixed to some mounting system) in time when it will be moved along a "smooth" but otherwise arbitrary trajectory. Ideally the input deck can be generated from NX Advanced Simulation and no special knowledge about Nastran syntax is required.

a) Think first of an cantilever beam which has one axis of rotation not fixed. The angular velocity increases smoothly from 0 to a certain value (at time 1 second) and decreases to 0 (at time 2 second). At time 1 second the resulting angle will be 45 degree, so this will not be a "small rotation".

For displacements (DOF1-3) on can define a transient exitation load with enforced motion load. The displacement is differientiated and results in  a load.

For DOF4-6 I have been told that this holds only for small rotation.

b) Think of a cantilever beam with an axis of rotation changing in time. For a more complex rotation the question arises how to define the exitation of  DOF4-6. The order of rotations about the x,y and z-axis is significant.

Ideally the proposed solution follows "The Intertial Loads Approach"