# Pressure Action System

Set up Pressure boundary conditions

## Description

The Pressure Action, given in the input file as simply Pressure, is designed to simplify the input file when several variables have the same pressure boundary condition magnitude applied in the normal component. Hydrostatic stress is a good example of a use case for the Pressure Action.

## Constructed MooseObjects

The Pressure Action is used to construct the Pressure boundary condition in all directions.

Table 1: Correspondence Among Action Functionality and MooseObjects

FunctionalityReplaced ClassesAssociated Parameters
A pressure traction forcePressure BCdisplacements : a string of the displacement variables to which the Pressure BC should be applied

The Pressure Action only applies the pressure traction in the same component direction as the displacements variables are listed. That is, for the argument displacements = 'disp_x disp_y disp_z', the Pressure Action will create three separate Pressure BCs:

• For the variable disp_x, the parameter setting component = 0 is used

• For the variable disp_y, the parameter setting component = 1 is used

• For the variable disp_z, the parameter setting component = 2 is used

note:Displacement Variable-Component Relationship is Relative

Note that the location of each of the variables in the displacements string determines the value of the corresponding component.

As in the Pressure boundary condition, the magnitude of the Pressure boundary condition can be specified as either a scalar (use the input parameter factor) or a function parameter.

## Example Input Syntax


[./Pressure]
[./Side1]
boundary = 1
function = rampConstant
displacements = 'disp_x disp_y disp_z'
[../]
[./Side2]
boundary = 2
function = zeroRamp
displacements = 'disp_x disp_y disp_z'
[../]
[./Side3]
boundary = 3
function = rampUnramp
displacements = 'disp_x disp_y disp_z'
[../]
[../]
(modules/tensor_mechanics/test/tests/pressure/pressure_test.i)

## Input Parameters

• boundaryThe list of boundary IDs from the mesh where the pressure will be applied

C++ Type:std::vector

Options:

Description:The list of boundary IDs from the mesh where the pressure will be applied

### Required Parameters

• functionThe function that describes the pressure

C++ Type:FunctionName

Options:

Description:The function that describes the pressure

• save_in_disp_xThe save_in variables for x displacement

C++ Type:std::vector

Options:

Description:The save_in variables for x displacement

• save_in_disp_yThe save_in variables for y displacement

C++ Type:std::vector

Options:

Description:The save_in variables for y displacement

• disp_zThe z displacement

C++ Type:NonlinearVariableName

Options:

Description:The z displacement

• disp_yThe y displacement

C++ Type:NonlinearVariableName

Options:

Description:The y displacement

• disp_xThe x displacement

C++ Type:NonlinearVariableName

Options:

Description:The x displacement

• save_in_disp_zThe save_in variables for z displacement

C++ Type:std::vector

Options:

Description:The save_in variables for z displacement

• inactiveIf specified blocks matching these identifiers will be skipped.

C++ Type:std::vector

Options:

Description:If specified blocks matching these identifiers will be skipped.

• factor1The factor to use in computing the pressure

Default:1

C++ Type:double

Options:

Description:The factor to use in computing the pressure

• active__all__ If specified only the blocks named will be visited and made active

Default:__all__

C++ Type:std::vector

Options:

Description:If specified only the blocks named will be visited and made active

• alpha0alpha parameter for HHT time integration

Default:0

C++ Type:double

Options:

Description:alpha parameter for HHT time integration

• displacementsThe displacements appropriate for the simulation geometry and coordinate system

C++ Type:std::vector

Options:

Description:The displacements appropriate for the simulation geometry and coordinate system