Plate Loads

Plate pressures are surface loads applied to quadrilateral or triangular plate elements. Use them for slab area loads, wall and tank pressure, roof pressure, and other loads distributed over a plate surface.

Uniform and Linear Pressure

Uniform pressure applies one magnitude to a plate group or to individual plate elements. Linear ramp varies from a start pressure to an end pressure across an authored plate group.

Linear ramps require a Plate Group because the group geometry defines the start, end, and local variation axes. Element-only targets therefore support Uniform pressure only.

Adding Plate Loads

Using the Loads Dialog

  1. Click Loads in the ribbon to open the Loads dialog.
  2. Select the Plate Pressure tab.
  3. Select a load case and either a Plate Group or individual Element(s).
  4. Choose Uniform and enter Magnitude, or choose Linear ramp and enter Start pressure, End pressure, and Varies along.
  5. Select the load direction.

Using the Context Menu or Properties Panel

  1. Select one or more plate elements in the 3D view.
  2. Right-click and choose Plate Pressure Loads, or use Plate Pressure from the selected plate's Loads section in the properties panel.
  3. The Loads dialog opens on the Plate Pressure tab with the selected plate elements pre-filled.

Plate Pressure Properties

  • Case: The load case ID this load belongs to.
  • Plate Group: A meshed plate group. Selecting a group applies the pressure to every tile in that group.
  • Element(s): One or more individual plate element IDs. This is disabled when a Plate Group is selected.
  • Distribution: Uniform or Linear ramp. Linear ramp is available for Plate Group targets.
  • Magnitude: The Uniform pressure value in the current pressure unit, such as kPa or psf.
  • Start pressure / End pressure: The pressure values at the two ends of a Linear ramp.
  • Varies along: The plate group local x or local y axis used to vary the ramp magnitude.
  • Direction: Normal, Global X, Global Y, or Global Z.

Ramp Axes

A Linear ramp follows q(s) = q_start + (q_end - q_start)s, where q is pressure intensity in the current pressure unit, q_start and q_end are the Start pressure and End pressure, and s runs from 0 to 1 along the selected group axis. This axis controls the pressure magnitude only; it is independent of the load Direction.

  • Planar groups: Local x and local y follow the shell-axis arrows displayed on the model. The ramp runs from Start pressure on the negative side of the selected axis to End pressure on its positive side.
  • Cylinder walls: Local x runs circumferentially from the start-angle seam in the increasing-angle direction, and local y runs from base to top.
  • Cylinder floor/roof caps: Local y runs from centre to rim. Local x uses the increasing-angle direction on the floor and decreasing-angle direction on the roof.
  • Circular/annular plates: Local x runs clockwise from the start-angle seam, and local y runs from the centre or inner edge to the outer rim.
  • Cone/frustum shells: Local x runs from the seam in the increasing-angle direction, and local y runs from base to top along the sloping meridian.

On any closed circumferential group, a local-x ramp is not periodic: the closing seam transitions from the End pressure back to the Start pressure.

Mesh-Stepped Ramp and Validation

The solver applies each tile's area-average pressure, so a Linear ramp appears in mesh-stepped uniform bands on the canvas and in analysis rather than as an exact within-element gradient.

  • One tile band along the selected axis cannot represent a ramp and blocks analysis.
  • Two or three bands are allowed but produce a coarse-ramp warning.
  • Use at least four bands along the ramp axis and check mesh convergence where the pressure gradient matters.

Direction

  • Normal: Pressure acts perpendicular to the plate, along the plate's local +z normal.
  • Global X / Y / Z: Pressure acts along the fixed global axis per actual plate surface area. The solver resolves it into perpendicular and in-plane components for each plate.

For full axis and sign details, see Sign Conventions.

Applying to Groups or Elements

For a meshed slab, wall, tank, or panel, use Plate Group when the whole authored surface should receive the load or when defining a Linear ramp. Use Element(s) for Uniform pressure on selected tiles only.

The Element(s) field supports the same range/list style used elsewhere in the app, such as 12-20 or 12,15,18.

Load Visualization

Plate pressure loads are displayed when the Loads display is enabled. They use the load case colour and follow the distributed-load scale, so hold L and scroll to adjust their visual size.

Mass and Analysis

Plate pressure loads participate in static analysis as applied loads. Gravity-direction plate pressures can also contribute mass in modal analysis according to the selected mass/load pattern.

Units

Pressure values use the current unit system, for example kPa in metric or psf in imperial. Units can be changed in Settings.