## GEOMETRY_PIPE

#### Geometries

*GEOMETRY_PIPE
"Optional title"
gid, csysid
$x_1$, $y_1$, $z_1$, $x_2$, $y_2$, $z_2$, $R_1$, $R_2$
$R_3$, $R_4$, $v_x$, $v_y$, $v_z$, $\alpha$

### Parameter definition

Variable
Description
gid
Geometry identification number
csysid
Local coordinate system ID
default: global coordinate system is used
$x_1$, $y_1$, $z_1$
Face center coordinate 1
$x_2$, $y_2$, $z_2$
Face center coordinate 2
$R_1$
$R_2$
$R_3$
default: $R_3 = R_1$
$R_4$
default: $R_4 = R_2$
$v_x$, $v_y$, $v_z$
Radial vector at zero tangential angle
default: not used
$\alpha$
Pipe sector angle
default: $360^\circ$

### Description

This command is used to define a straight pipe or cylinder in space, with its face center coordinates at ($x_1$, $y_1$, $z_1$) and ($x_2$, $y_2$, $z_2$). Note that the smaller of $R_1$ and $R_2$ is automatically taken as the inner radius.

### Example

###### Different variants of pipe geometries

Example that highlights the various geometries that can be created by using the different parameters in the command.

*UNIT_SYSTEM SI *PARAMETER x1 = 0 y1 = 0 z1 = 0 x2 = 0 y2 = 0.3 z2 = 0 dx = 0.4 R1 = 0.15 R2 = 0.1 *GEOMETRY_PIPE "Cylinder - only specify R1 (R2 is set to 0)" 1 [%x1], [%y1], [%z1], [%x2], [%y2], [%z2], [%R1] *GEOMETRY_PIPE "Pipe - specify both R1 and R2" 2 [%x1+%dx], [%y1], [%z1], [%x2+%dx], [%y2], [%z2], [%R1], [%R2] *GEOMETRY_PIPE "Cone, specify R1 and R3" 3 [%x1+2*%dx], [%y1], [%z1], [%x2+2*%dx], [%y2], [%z2], [%R1] 0.05 *GEOMETRY_PIPE "Pipe with coned interior, specify all R1-R4" 4 [%x1+3*%dx], [%y1], [%z1], [%x2+3*%dx], [%y2], [%z2], [%R1], [%R2] [%R1], 0.05 *GEOMETRY_PIPE "A sector of a pipe. Specify vx, vy, vx and angle" 5 [%x1+4*%dx], [%y1], [%z1], [%x2+4*%dx], [%y2], [%z2], [%R1], [%R2] [%R1], 0.05, 1, 0, 0, 130 *GEOMETRY_PIPE "Sector of a cylinder, drawn from a different radial vector" 6 [%x1+5*%dx], [%y1], [%z1], [%x2+5*%dx], [%y2], [%z2], [%R1] [%R1], 0, 0, 0, 1, 90 *END
###### Pipe with internal pressure

Example of a pipe with an internal pressure. GEOMETRY_PIPE is used to apply a fixed boundary condition for the outer surface of the pipe.

*UNIT_SYSTEM SI *PARAMETER %tend = 0.01 *TIME [%tend] *OUTPUT [%tend/5] *COMPONENT_PIPE "Pipe with outer radius 0.5 and inner radius 0.4" 1, 1, 6, 10, 1 -2.0, 0.0, 0.0, 2.0, 0.0, 0.0, 0.5, 0.4 *PART 1, 1, , , 45 *MAT_ELASTIC 1, 7800.0, 210.0e9, 0.3 *CHANGE_P-ORDER P, 1, 3 *GEOMETRY_SEED_COORDINATE "Geometry used to apply internal pressure" 2 0.0, 0.0, 0.0, , 1 *LOAD_PRESSURE 2 G, 2, 123 *FUNCTION 123 1e11*(t/%tend) *GEOMETRY_PIPE "Geometry selecting the outer nodes of the pipe" 1 -2.01, 0.0, 0.0, 2.0, 0.0, 0.0, 0.52, 0.48 *BC_MOTION 1 G, 1, XYZ *END