Rigid Element Library

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

This page discusses:

See Also
Rigid Elements
In Other Guides
*RIGID BODY

Products Abaqus/Standard Abaqus/Explicit

Element Types

2D Rigid Elements

R2D2

2-node, linear link (for use in plane strain or plane stress)

RAX2

2-node, linear link (for use in axisymmetric planar geometries)

RB2D2(S)

2-node, rigid beam

Secondary Degrees of Freedom

R2D2 and RAX2: 1, 2

RB2D2: 1, 2, 6

Main Degrees of Freedom

R2D2, RAX2, and RB2D2: 1, 2, 6 at the rigid body reference node

Additional Solution Variables

None.

3D Rigid Elements

R3D3

3-node, triangular facet

R3D4

4-node, bilinear quadrilateral

RB3D2(S)

2-node, rigid beam

Secondary Degrees of Freedom

R3D3 and R3D4: 1, 2, 3

RB3D2: 1, 2, 3, 4, 5, 6

Main Degrees of Freedom

1, 2, 3, 4, 5, 6 at the rigid body reference node

Additional Solution Variables

None.

Nodal Coordinates Required

R2D2 and RB2D2: X, Y

RAX2: r, z

R3D3, R3D4, and RB3D2: X, Y, Z

Element Property Definition

For R2D2, RB2D2, and RB3D2 elements you can specify the cross-sectional area of the element. In Abaqus/Standard if no area is given, unit area is assumed; the area is required in Abaqus/Explicit.

For RAX2, R3D3, and R3D4 elements you can specify the thickness of the element. In Abaqus/Standard if no thickness is given, unit thickness is assumed; the thickness is required in Abaqus/Explicit.

The cross-sectional area or element thickness is used for the purpose of defining body forces, which are given in units of force per unit volume, and, in Abaqus/Explicit, determining the total mass.

Input File Usage

RIGID BODY

Element-Based Loading

Distributed Loads

Distributed loads are available for elements with displacement degrees of freedom. They are specified as described in Distributed Loads.

*dload

Available for R2D2 elements only:

  1. Load ID (*DLOAD): BX(S)
  2. FL−3

  3. Body force in global X-direction.

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

  3. Body force in global Y-direction.

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

  3. Nonuniform body force in global X-direction with magnitude supplied via user subroutine DLOAD.

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

  3. Nonuniform body force in global Y-direction with magnitude supplied via user subroutine DLOAD.

  1. Load ID (*DLOAD): CENT(S)
  2. FL−4 (ML−3T−2)

  3. Centrifugal load (magnitude is input as ρ⁢ω2, where ρ is the mass density per unit volume and ω is the angular velocity).

  1. Load ID (*DLOAD): CORIO(S)
  2. FL−4T (ML−3T−1)

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

  1. Load ID (*DLOAD): P(E)
  2. FL−2

  3. Pressure on the element surface. The pressure is positive in the direction of the positive element normal.

  1. Load ID (*DLOAD): PNU(E)
  2. FL−2

  3. Nonuniform pressure on the element surface with magnitude supplied via user subroutine VDLOAD. The pressure is positive in the direction of the positive element normal.

*dload

Available for RAX2 elements only:

  1. Load ID (*DLOAD): BR(S)
  2. FL−3

  3. Body force per unit volume in the radial direction.

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

  3. Body force per unit volume in the axial direction.

  1. Load ID (*DLOAD): BRNU(S)
  2. FL−3

  3. Nonuniform body force per unit volume in the radial direction, with the magnitude supplied via user subroutine DLOAD.

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

  3. Nonuniform body force per unit volume in the z-direction, with the magnitude supplied via user subroutine DLOAD.

  1. Load ID (*DLOAD): CENT(S)
  2. FL−4 (ML− 3T−2)

  3. Centrifugal load (magnitude given as ρω​2, where ρ is the mass density and ω is the angular speed). Since only axisymmetric deformation is allowed, the spin axis must be the z-axis.

  1. Load ID (*DLOAD): HP(S)
  2. FL−2

  3. Hydrostatic pressure on the element surface and linear in global Z. The pressure is positive in the direction of the positive element normal.

  1. Load ID (*DLOAD): P
  2. FL−2

  3. Pressure on the element surface. The pressure is positive in the direction of the positive element normal.

  1. Load ID (*DLOAD): PNU
  2. FL−2

  3. Nonuniform pressure on the element surface with the 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): TRSHR
  2. FL−2

  3. Shear traction on the element surface.

  1. Load ID (*DLOAD): TRSHRNU(S)
  2. FL−2

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

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

  3. General traction on the element surface.

  1. Load ID (*DLOAD): TRVECNU(S)
  2. FL−2

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

*dload

Available for R3D3 and R3D4 elements only:

  1. Load ID (*DLOAD): BX(S)
  2. FL−3

  3. Body force in the global X-direction.

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

  3. Body force in the global Y-direction.

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

  3. Body force in the global Z-direction.

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

  3. Nonuniform body force in the global X-direction with magnitude supplied via user subroutine DLOAD.

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

  3. Nonuniform body force in the global Y-direction with magnitude supplied via user subroutine DLOAD.

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

  3. Nonuniform body force in the global Z-direction with magnitude supplied via user subroutine DLOAD.

  1. Load ID (*DLOAD): CENT(S)
  2. FL−4 (ML−3T−2)

  3. Centrifugal load (magnitude is input as ρ⁢ω2, where ρ is the mass density per unit volume and ω is the angular velocity).

  1. Load ID (*DLOAD): CORIO(S)
  2. FL−4T (ML−3T−1)

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

  1. Load ID (*DLOAD): HP(S)
  2. FL−2

  3. Hydrostatic pressure on the element surface and linear in global Z. The pressure is positive in the direction of the positive element normal.

  1. Load ID (*DLOAD): P
  2. FL−2

  3. Pressure on the element surface. The pressure is positive in the direction of the positive element normal.

  1. Load ID (*DLOAD): PNU
  2. FL−2

  3. Nonuniform pressure on the element 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): TRSHR
  2. FL−2

  3. Shear traction on the element surface.

  1. Load ID (*DLOAD): TRSHRNU(S)
  2. FL−2

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

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

  3. General traction on the element surface.

  1. Load ID (*DLOAD): TRVECNU(S)
  2. FL−2

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

Abaqus/Aqua Loads

Abaqus/Aqua loads are specified as described in Abaqus/Aqua Analysis.

*cload/ *dload

Available for R3D3 and R3D4 elements only:

  1. Load ID (*CLOAD/ *DLOAD): PB
  2. FL−2

  3. Buoyancy force.

*cload/ *dload

Available for RB2D2 and RB3D2 elements only:

  1. Load ID (*CLOAD/ *DLOAD): FDD
  2. FL−1

  3. Transverse fluid drag force.

  1. Load ID (*CLOAD/ *DLOAD): FD1
  2. F

  3. Fluid drag force on the first end of the rigid link (node 1).

  1. Load ID (*CLOAD/ *DLOAD): FD2
  2. F

  3. Fluid drag force on the second end of the rigid link (node 2).

  1. Load ID (*CLOAD/ *DLOAD): FDT
  2. FL−1

  3. Tangential fluid drag load.

  1. Load ID (*CLOAD/ *DLOAD): FI
  2. FL−1

  3. Transverse fluid inertia load.

  1. Load ID (*CLOAD/ *DLOAD): FI1
  2. F

  3. Fluid inertia load on the first end of the rigid link (node 1).

  1. Load ID (*CLOAD/ *DLOAD): FI2
  2. F

  3. Fluid inertia load on the second end of the rigid link (node 2).

  1. Load ID (*CLOAD/ *DLOAD): PB
  2. FL−1

  3. Buoyancy force (with closed-end condition).

  1. Load ID (*CLOAD/ *DLOAD): WDD
  2. FL−1

  3. Transverse wind drag force.

  1. Load ID (*CLOAD/ *DLOAD): WD1
  2. F

  3. Wind drag force on the first end of the rigid link (node 1).

  1. Load ID (*CLOAD/ *DLOAD): WD2
  2. F

  3. Wind drag force on the second end of the rigid link (node 2).

Surface-Based Loading

Distributed Loads

Surface-based distributed loads are available for elements with displacement degrees of freedom. They are specified as described in Distributed Loads.

*dsload

Available for RAX2, R3D3, and R3D4 elements only:

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

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

  1. Load ID (*DSLOAD): P
  2. FL−2

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

  1. Load ID (*DSLOAD): PNU
  2. FL−2

  3. Nonuniform pressure on the element surface with the 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): TRSHR
  2. FL−2

  3. Shear traction on the element surface.

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

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

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

  3. General traction on the element surface.

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

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

Element Output

None.

Node Ordering on Elements