GRID

Model Element

Description

GRID defines an NLFE node in 3D space. The definition of a GRID contains the following information:

•	Current location in space (X, Y and Z coordinates)

•	Relaxed location in space (X, Y and Z coordinates)

•	Current gradient vectors in space (X, Y and Z gradient vectors)

•	Relaxed gradient vectors in space (X, Y and Z gradient vectors)

These are called the nodal co-ordinates for this GRID.

Format

<GRID

id = "integer"

x = "real"

y = "real"

z = "real"

rx = "string"

ry = "string"

rz = "string"

x0 = "real"

y0 = "real"

z0 = "real"

rx0 = "string"

ry0 = "string"

rz0 = "string"

xd = "real"

yd = "real"

zd = "real"

rxd = "real"

ryd = "real"

rzd = "real"

Attributes

Unique GRID identification number.

The current X, Y and Z position of the GRID.

The relaxed X, Y and Z positions of the GRID.

The X, Y and Z gradient vectors for the GRID. Each vector is specified as a string of three space separated values that represent the vector components.

rx0

ry0

rz0

The X, Y and Z relaxed position gradient vectors for the GRID. Each vector is specified as a string of three space separated values that represent the vector components.

The X, Y and Z velocity of the grid.

Default for all three is 0.

rxd

ryd

rzd

The time of the X, Y and Z gradient vector.

Default for all three is 0.

Comments

1.	Each GRID has a unique identification number with respect to other GRIDs.

2.	The number of nodal coordinates depends on the element type. For instance, a CABLE element can be specified using only one gradient vector however other elements such as the BEAM element require two gradient vectors.

3.	The nodal positions are required to be defined for each NLFE body.

You may define the relaxed nodal coordinates (x0, y0, z0, rx0, ry0 and rz0) for the NLFE body. If these are different than the model configuration (x, y, z, rx, ry and rz), then the NLFE body will try to regain its relaxed configuration which will produce internal stresses. This may be used to model preload in the NLFE body. If the relaxed nodal coordinates are not defined, MotionSolve assumes the relaxed configuration of the component to be the same as the model configuration of the component and no internal stresses are generated.

Example

The following is an example of a GRID defined at the origin: