/FRAME/MOV

Block Format Keyword

/FRAME/MOV - Moving Frames

Describes moving frames. Relative motion with respect to a reference frame.

Field	Contents
frame_ID	Reference frame identifier - must be different from all skew identifiers. (Integer, maximum 10 digits)
frame_title	Reference frame title (Character, maximum 100 characters)
node_ID1	Node identifier N1 (Integer)
node_ID2	Node identifier N2 (Integer)
node_ID3	Node identifier N3 (Integer)

1.	Let a moving reference frame t(A,u,v,w).

2.	For each time t, the frame position and orientation are determined via its original position xA and a rotation (orientation) matrix R.

3.	Let w be the instantaneous rotational velocity of .

4.	For each time t, the local coordinates xl of a point M with respect to the frame are related to its coordinates xG into the global system, as follows:

5.	The relative displacement of M between time 0 and t, with respect to the frame is related to its displacement with regard to the global system, as follows:

6.	The relative velocity of M with respect to the frame is related to its velocity with regard to the global system, as follows:

where, is the driving velocity; that is the velocity of the point coincident with M at time t and fixed with respect to the reference frame.

7.	The relative acceleration of M with respect to the frame M is related to its acceleration with regard to the global system, as follows:

Where, is the driving acceleration and is the acceleration, due to Coriolis forces.

8.	For a moving reference frame, the reference frame position and orientation vary with time and are defined by N1, N2 and N3.

The origin of the frame is defined by the position of N1.

Nodes N1 and N2 define X’:

Plane N1, N2 and N3 define Y’:

Z’ is normal to plane X’ Y’

and Y’ is recomputed:

9.	In a 2D analysis N1 and N2 define Y’.

frame_move_image

Reference frame identifier must be different from all skew identifiers.