Block Format Keyword Defines pressure load on a surface for 3D surface.

Note: This pressure load can be used only for 3D analysis.

## Format

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
surf_ID Iload sens_ID Inorm Dir Skew_ID
fct_IDT Ascalex Fscaley
Add the line for each contact interface (up to 5)
(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
Inter_IDi Gap_shift

## Definition

Field Contents SI Unit Example

(Integer, maximum 10 digits)

unit_ID (Optional) Unit identifier.

(Integer, maximum 10 digits)

(Character, maximum 100 characters)

surf_ID Surface identifier.

(Integer)

= 1(Default)
Pressure is applied when there is no contact.
= 2
Pressure is applied when there is contact.

(Integer)

sens_ID Sensor identifier.
0
Pressure load is applied after sensor activation (the time function is shifted in time).

(Integer)

Inorm Pressure direction applied:
= 1 (Default)
Along the segment normal direction.
= 2
On the defined direction Dir.
= 3
On the defined direction Dir and scaled by the segment normal direction.

(Integer)

Dir Direction where the pressure is applied (read only for Inorm=2,3).
X
X direction in local or global coordinate system.
Y
Y direction in local or global coordinate system.
Z
Z direction in local or global coordinate system.

(Integer)

Skew_ID Local coordinate system identifier for the direction where the pressure is applied (read only for Inorm=2,3).
= 0
Global coordinate system is used.

(Integer)

fct_IDT Time function identifier.

(Integer)

Ascalex Abscissa (Time) scale factor.

Default = 1.0 (Real)

Fscaley Ordinate scale factor.

Default = 1.0 (Real)

Inter_IDi Contact interfaces identifier to activate the pressure loading. Up to 5 interfaces can be defined.

(Integer)

Gap_shift Gap shift for the contact detection.

Default = 0 (Real)

1. The pressure direction is defined as:
• With Inorm=1, positive pressure acts in segment normal direction $n={N}_{1}{N}_{3}×{N}_{2}{N}_{4}$ .

With ${N}_{1}$ , ${N}_{2}$ , ${N}_{3}$ , and ${N}_{4}$ being the nodes of the segment in the surface definition.

• With Inorm=2, pressure is applied along the defined direction.
• With Inorm=3, pressure is applied along the defined direction and scaled by the segment normal direction. There is no more pressure for the segment normal direction perpendicular to the defined direction.
2. The Ascalex and Fscaley are used to scale the abscissa (time) and ordinate (pressure).
The actual pressure function value is calculated as:(1)
$\mathrm{F}\left(t\right)=Fscal{e}_{y}\cdot {\mathrm{f}}_{T}\cdot \left(\frac{t}{Ascal{e}_{x}}\right)$

Where, ${\mathrm{f}}_{T}$ is the function of fct_IDT.

3. The contact is detected when the distance between the main and the secondary surface is equal to or less than the contact gap + Gap_shift.
4. With Iload=0, pressure will be applied only on the facets defined in surf_ID, which are not in contact interface(s) Inter_IDi.
5. With Iload=1, the pressure will be applied only on the facets defined in surf_ID which are in contact interface(s) Inter_IDi.
6. Pressure load is canceled when all the elements associated to the segment are deleted.