/RWALL

Block Format Keyword

/RWALL - Rigid Walls

Description

Defines the following types of rigid walls: Infinite Plane, Infinite Cylinder, Sphere and Parallelogram.

Format

(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)	(10)
/RWALL/type/rwall_ID/unit_ID
rwall_title
node_ID	Slide	grnd_ID1	grnd_ID2
Dsearch		fric				ffac		ifq

If node_ID = 0

(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)	(10)
XM		YM		ZM

If node_ID ≠ 0

(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)	(10)
Mass		VX0		VY0		VZ0

If type is Plane, Cyl, Paral.

(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)	(10)
XM1		YM1		ZM1

If type is Paral.

(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)	(10)
XM2		YM2		ZM2

Field	Contents	SI Unit Example
type	Rigid wall type keyword (see table below)
rwall_ID	Rigid wall identifier (Integer, maximum 10 digits)
unit_ID	Optional unit identifier (Integer, maximum 10 digits)
rwall_title	Rigid wall title (Character, maximum 100 characters)
node_ID	Node identifier (moving rigid wall) (Integer)
Slide	Sliding flag (Integer) = 0: Sliding = 1: Tied = 2: Sliding with friction
grnd_ID1	Node group defining slave nodes to be added to the rigid wall (Integer)
grnd_ID2	Node group defining slave nodes to be deleted from the rigid wall (Integer)
Dsearch	Distance for slave search (Real)
fric	Friction (Real)
	Diameter of the sphere (Real)
ffac	Filtering factor Default = 0.0 (Real)
ifq	Filtering flag (Comments 5 through 8) Default = 0 (Integer)
XM	X coordinate of M (Real)
YM	Y coordinate of M (Real)
ZM	Z coordinate of M (Real)
Mass	Mass of the rigid wall (Real)
VX0	Initial velocity in X direction (Real)
VY0	Initial velocity in Y direction (Real)
VZ0	Initial velocity in Z direction (Real)
XM1	X coordinate of M1 (Real)
YM1	Y coordinate of M1 (Real)
ZM1	Z coordinate of M1 (Real)
XM2	X coordinate of M2 (Real)
YM2	Y coordinate of M2 (Real)
ZM2	Z coordinate of M2 (Real)

Type	Description
PLANE	Plane
CYL	Cylinder of diameter
SPHER	Sphere of diameter
PARAL	Parallelogram

Type	Description	Sketch
PLANE	MM1 defines the normal direction
CYL	MM1 defines the axis of the cylinder
SPHER	M is the center of the sphere
PARAL	MM1 and MM2 define the parallelogram

1.	The first input defines the rigid wall coordinates of one point M or a node_ID in case of moving rigid wall.

2.	The next input is the coordinate of a point M1 and possibly a point M2 (in case of a moving wall, M1 and M2 have the same motion as node_ID).

3.	The slave nodes to a rigid wall can be defined as a group of nodes and/or as nodes initially at a distance less than the distance (Dsearch) from the rigid wall.

4.	The friction filtering option is only available for a slide rigid wall with friction (Slide=2).

5.	If ifq ≠ 0, the tangential (friction) forces in each slave node in contact are filtered using a simple rule:

FT = * F'T + (1 - ) * F'T-1

Where, FT is the tangential force, F'T is the tangential force at time t, F'T-1 is the tangential force at time t-1, and is the filtering coefficient.

The flag ifq defines a method for filtering, coefficient.

6.	If ifq =1, filtering coefficient is directly input by you: = ffac

7.	If ifq =2, corresponds to a 3dB filtering level for user-defined frequency:

= 2dt * freq, where dt = time step, and freq = ffac

8.	If ifq =3, corresponds to a 3dB filtering level for user-defined frequency (frequency defined in terms of time step number):

= 2 / N, with 1/freq = T = N * dt, and N = ffac

9.	The sphere (SPHER) and parallelogram (PARAL) are not infinite. For parallelograms, the normal is defined using:

and the diameter of the sphere is definited using .

10.	Nodal thickness of rigid wall slave nodes is not taken into account.