General Surface Element Library

This section provides a reference to the surface elements available in Abaqus/Standard, Abaqus/Explicit and Abaqus/Aqua.

This page discusses:

See Also
Surface Elements
In Other Guides
*SURFACE SECTION
*REBAR LAYER

Products Abaqus/Standard Abaqus/Explicit Abaqus/CAE Abaqus/Aqua

Element Types

SFM3D3

3-node triangle

SFM3D4(S)

4-node quadrilateral

SFM3D4R

4-node quadrilateral, reduced integration

SFM3D6(S)

6-node triangle

SFM3D8(S)

8-node quadrilateral

SFM3D8R(S)

8-node quadrilateral, reduced integration

Active Degrees of Freedom

1, 2, 3

Additional Solution Variables

None.

Nodal Coordinates Required

X, Y, Z

Element Property Definition

Input File Usage

Use the following option to define surface element properties:

            
              SURFACE SECTION

If rebar are being defined, use the following option in conjunction with the SURFACE SECTION option:

 REBAR LAYER

Use the following option to define a mass density per unit area:

SURFACE SECTION, DENSITY=number

Use the following option to define the free surface of water in an Abaqus/Aqua analysis:

SURFACE SECTION, AQUAVISUALIZATION=YES

Abaqus/CAE Usage

Property module: Create Section: select Shell as the section Category and Surface as the section Type, Rebar Layers (optional)

You cannot define the mass per unit area or the free surface of water for a surface section in Abaqus/CAE.

Element-Based Loading

Distributed Loads

Distributed loads are specified as described in Distributed Loads. Gravity, centrifugal, rotary acceleration, and Coriolis force loads apply only if the surface elements have rebar defined or if the elements have a defined density.

*dload
  1. Load ID (*DLOAD): BX
  2. Body force
  3. FL−2

  4. Body force in the global X-direction.

  1. Load ID (*DLOAD): BY
  2. Body force
  3. FL−2

  4. Body force in the global Y-direction.

  1. Load ID (*DLOAD): BZ
  2. Body force
  3. FL−2

  4. Body force in the global Z-direction.

  1. Load ID (*DLOAD): BXNU
  2. Body force
  3. FL−2

  4. Nonuniform body force in the global X-direction with magnitude supplied via user subroutine DLOAD in Abaqus/Standard and VDLOAD in Abaqus/Explicit.

  1. Load ID (*DLOAD): BYNU
  2. Body force
  3. FL−2

  4. Nonuniform body force in the global Y-direction with magnitude supplied via user subroutine DLOAD in Abaqus/Standard  and VDLOAD in Abaqus/Explicit.

  1. Load ID (*DLOAD): BZNU
  2. Body force
  3. FL−2

  4. Nonuniform body force in the global Z-direction with magnitude supplied via user subroutine DLOAD in Abaqus/Standard and VDLOAD in Abaqus/Explicit.

  1. Load ID (*DLOAD): CENT (S)
  2. Not supported
  3. FL−3 (ML−2T−2)

  4. Centrifugal load (magnitude is input as ρ⁢ω2, where ρ is the mass density per unit area, ω is the angular speed).

  1. Load ID (*DLOAD): CENTRIF (S)
  2. Rotational body force
  3. T−2

  4. Centrifugal load (magnitude is input as ω2, where ω is the angular speed).

  1. Load ID (*DLOAD): CORIO (S)
  2. Coriolis force
  3. FL−3T (ML−2T−1)

  4. Coriolis force (magnitude is input as ρ⁢ω, where ρ is the mass density per unit area, ω is the angular speed). The load stiffness due to Coriolis loading is not accounted for in direct steady-state dynamics analysis.

  1. Load ID (*DLOAD): GRAV
  2. Gravity
  3. LT−2

  4. Gravity loading in a specified direction (magnitude is input as acceleration).

  1. Load ID (*DLOAD): HP (S)
  2. Not supported
  3. FL−2

  4. Hydrostatic pressure applied to the element reference surface and linear in global Z. The pressure is positive in the direction of the positive element normal.

  1. Load ID (*DLOAD): P
  2. Pressure
  3. FL−2

  4. Pressure applied to the element reference surface. The pressure is positive in the direction of the positive element normal.

  1. Load ID (*DLOAD): PNU
  2. Not supported
  3. FL−2

  4. Nonuniform pressure applied to the element reference surface with magnitude supplied via user subroutine DLOAD in Abaqus/Standard and VDLOAD in Abaqus/Explicit. The pressure is positive in the direction of the positive element normal.

  1. Load ID (*DLOAD): ROTA (S)
  2. Rotational body force
  3. T−2

  4. Rotary acceleration load (magnitude is input as α, where α is the rotary acceleration).

  1. Load ID (*DLOAD): SBF (E)
  2. Not supported
  3. FL−5T2

  4. Stagnation body force in global X-, Y-, and Z-directions.

  1. Load ID (*DLOAD): SP (E)
  2. Not supported
  3. FL−4T2

  4. Stagnation pressure applied to the element reference surface.

  1. Load ID (*DLOAD): TRSHR
  2. Surface traction
  3. FL−2

  4. Shear traction on the element reference surface.

  1. Load ID (*DLOAD): TRSHRNU (S)
  2. Not supported
  3. FL−2

  4. Nonuniform shear traction on the element reference surface with magnitude and direction supplied via user subroutine UTRACLOAD.

  1. Load ID (*DLOAD): TRVEC
  2. Surface traction
  3. FL−2

  4. General traction on the element reference surface.

  1. Load ID (*DLOAD): TRVECNU (S)
  2. Not supported
  3. FL−2

  4. Nonuniform general traction on the element reference surface with magnitude and direction supplied via user subroutine UTRACLOAD.

  1. Load ID (*DLOAD): VBF (E)
  2. Not supported
  3. FL−4T

  4. Viscous body force in global X-, Y-, and Z-directions.

  1. Load ID (*DLOAD): VP (E)
  2. Not supported
  3. FL−3T

  4. Viscous surface pressure applied to the element reference surface. The pressure is proportional to the velocity normal to the element face and opposing the motion.

Foundations

Foundations are available only in Abaqus/Standard and are specified as described in Element Foundations.

*foundation
  1. Load ID (*FOUNDATION): F
  2. Elastic foundation
  3. FL−3

  4. Elastic foundation.

Surface-Based Loading

Distributed Loads

Surface-based distributed loads are specified as described in Distributed Loads.

*dsload
  1. Load ID (*DSLOAD): HP (S)
  2. Pressure
  3. FL−2

  4. Hydrostatic pressure on the element reference surface and linear in global Z. The pressure is positive in the direction opposite to the surface normal.

  1. Load ID (*DSLOAD): P
  2. Pressure
  3. FL−2

  4. Pressure on the element reference surface. The pressure is positive in the direction opposite to the surface normal.

  1. Load ID (*DSLOAD): PNU
  2. Pressure
  3. FL−2

  4. Nonuniform pressure on the element reference surface with magnitude supplied via user subroutine DLOAD in Abaqus/Standard and VDLOAD in Abaqus/Explicit. The pressure is positive in the direction opposite to the surface normal.

  1. Load ID (*DSLOAD): SP (E)
  2. Pressure
  3. FL−4T2

  4. Stagnation pressure applied to the element reference surface.

  1. Load ID (*DSLOAD): TRSHR
  2. Surface traction
  3. FL−2

  4. Shear traction on the element reference surface.

  1. Load ID (*DSLOAD): TRSHRNU (S)
  2. Surface traction
  3. FL−2

  4. Nonuniform shear traction on the element reference surface with magnitude and direction supplied via user subroutine UTRACLOAD.

  1. Load ID (*DSLOAD): TRVEC
  2. Surface traction
  3. FL−2

  4. General traction on the element reference surface.

  1. Load ID (*DSLOAD): TRVECNU (S)
  2. Surface traction
  3. FL−2

  4. Nonuniform general traction on the element reference surface with magnitude and direction supplied via user subroutine UTRACLOAD.

  1. Load ID (*DSLOAD): VP (E)
  2. Pressure
  3. FL−3T

  4. Viscous surface pressure applied to the element reference surface. The pressure is proportional to the velocity normal to the element surface and opposing the motion.

Incident Wave Loading

Surface-based incident wave loading is also available for these elements. See Acoustic and Shock Loads.

Element Output

Output is currently available only when the surface element is used to carry rebar layers. See Defining Reinforcement for details.

Node Ordering on Elements



 

Numbering of Integration Points for Output