Angle between a Vector and a Vector |
 
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Angle between a Vector and a Vector |
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The last type of Angles output is the angle between two vectors that you define. In order to define a vector, you associate a name or label with the vector, input the vector components in the global axes, and identify the node at which the vector is located. This node can be either a node of the structure finite element discretisation or a so-called auxiliary node. The significance of this last input is as follows. The vector components you input give the vector orientation at the undisplaced or initial position of the node. As the node displaces subsequently (either statically or dynamically), the rotations at the node are also applied to the vector so that the vector orientation changes with the motion of the node. The output in this case is again the true or actual angle between the two vectors, in the plane formed by both of these. Mathematically, the angle is again the arc-cosine of the dot product of unit vectors in the instantaneous directions of the vectors you specified. Again, this angle will be in the range 0° to 180°. This type of output might be used, for example, to monitor the rotation across a flex joint.
•*TIMETRACE is used to request the creation of timetrace plots. Specifically, TYPE=VECTOR_VECTOR_ANGLE is used to request a timetrace of the angle between two vectors.