/FRAME/MOV
Block Format Keyword Describes moving frames. Relative motion with respect to a reference frame.
Format
(1)  (2)  (3)  (4)  (5)  (6)  (7)  (8)  (9)  (10) 

/FRAME/MOV/frame_ID  
frame_title  
node_ID_{1}  node_ID_{2}  node_ID_{3}  Dir 
Definition
Field  Contents  SI Unit Example 

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_ID_{1}  Node identifier
N_{1} (Integer) 

node_ID_{2}  Node identifier
N_{2} (Integer) 

node_ID_{3}  Node identifier
N_{3} (Integer) 

Dir 
Default = X (Text) 
Comments
 Let a moving reference frame ${\Lambda}_{t}\left(A,u,v,w\right)$ .
 For each time t, the frame position and orientation are determined via its original position ${x}_{A}$ and a rotation (orientation) matrix $R$ .
 Let $w$ be the instantaneous rotational velocity of $\text{\Lambda}$ .
 For each time t,
the local coordinates
${x}_{l}$
of a point M with respect to
the frame are related to its coordinates
${x}_{G}$
into the global system, as:$${x}_{G}={x}_{A}+R{x}_{l}$$
 The relative displacement
${u}_{l}={x}_{l}{x}_{l}^{0}$
of M between time 0 and
t, with respect to the frame is related to its
displacement with regard to the global system, as:$${u}_{G}={u}_{A}+\left(R{R}^{0}\right){x}_{l}+R{u}_{l}$$
 The relative velocity of
M with respect to the frame is related to its velocity
with regard to the global system, as:$$R{v}_{l}={v}_{G}{v}_{e}$$
Where, ${v}_{e}={v}_{A}+\omega \times AM$ 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.
 The relative acceleration of
M with respect to the frame M is
related to its acceleration with regard to the global system,
as:$$R{\gamma}_{l}={\gamma}_{G}{\gamma}_{e}{\gamma}_{c}$$
Where, ${\gamma}_{e}={\gamma}_{A}+\raisebox{1ex}{$d\omega $}\!\left/ \!\raisebox{1ex}{$dt$}\right.\times AM+\omega \times \left(\omega \times AM\right)$ is the driving acceleration and ${\gamma}_{c}=2\omega \times {v}_{relative}$ is the acceleration, due to Coriolis forces.
 For a moving reference frame, the
reference frame position and orientation vary with time and are defined by
N_{1}, N_{2} and
N_{3}.The axis definition depends on the input for Dir.
 When Dir=X
node_ID_{1} amd node_ID_{2} define $X\text{'}$
node_ID_{1} and node_ID_{3} define $Y"$ $Z\text{\'}=X\text{\'}\Lambda Y"$
 $Y\text{'}={Z}^{\prime}\Lambda {X}^{\prime}$
 When Dir=Y
node_ID_{1} and node_ID_{2} define $Y\text{'}$
node_ID_{1} and node_ID_{3} define $Z"$ $X\text{'}={Z}^{\u2033}\Lambda {Y}^{\prime}$
 $Z\text{'}={X}^{\prime}\Lambda {Y}^{\prime}$
 Case Dir=Z
node_ID_{1} and node_ID_{2} define $Z\text{'}$
node_ID_{1} and node_ID_{3} define $X"$ ${Y}^{\prime}={X}^{\u2033}\Lambda {Z}^{\prime}$
 ${X}^{\prime}={Y}^{\prime}\Lambda {Z}^{\prime}$
The skew is defined by $X\text{'}$ , $Y\text{'}$ and $Z\text{'}$
 When Dir=X
 In a 2D analysis N_{1} and N_{2} define $Y\text{'}$ .
 Reference frame identifier must be different from all skew identifiers.