Solid Pretension

Bolt Modeling > 3D Bolt > Solid Pretension

Description

User can model the pretension in the tightened bolt by applying solid pretension. Solid pretension can be modeled for the following solver.

  1. Abaqus
  2. OptiStruct
  3. Permas
  4. Nastran
  5. Ansys
  6. ADVENTURECluster
  7. RADIOSS

Pretension Section

If the pretension section is already there in the bolt, then user can directly select that section and define pretension. The pretension section can also be created by defining a plane where to create the section. If the input is bolt body and user select the option "Find", it will automatically find the pretension section

Solid pretension for Abaqus, OptiStruct, RADIOSS, Ansys and ADVENTURECluster

Pretension section card will be written out using lock option, adjust length and force.

Pretension node ID can be defined explicitly to define pretension loads like force and constraint.

Note: For Abaqus, OptiStruct and RADIOSS, more than one solid pretension load cannot be applied on a pretension section. For Abaqus and OptiStruct the same pretension load can be added to different loadcases. The type and magnitude of the solid pretension load can be varied for each loadcase.

Solid pretension for NASTRAN and PERMAS

Solid pretension for NASTRAN is modeled by two types of connection.

  • MPC
  • 2. Contact

Solid pretension for PERMAS is modeled by three types of connection.

  • MPC
  • Contact
  • MPC-Type2
MPC

The bolt will be split into two halves and apart by the given gap, two RBEs will be created on the bottom face of the head portion of the bolt and top face of the thread portion of bolt respectively. The master nodes of these two RBEs will be connected by two bar elements and MPC will be created for the two nodes of bar elements as shown in the figure below.

Contact

The bolt will be split into two halves and apart by the given gap, two RBEs will be created on the bottom face of the head portion of the bolt and top face of the thread portion of bolt respectively. The master nodes of these two RBEs will be connected by weak spring with contact definition.

MPC-Type2

The bolt will be split into two halves and apart by the given gap, two RBEs will be created on the bottom face of the head portion of the bolt and top face of the thread portion of bolt respectively. The master nodes of these two RBEs will be connected by two bar elements and pretension force will be applied on the two nodes of bar elements as shown in the figure below.

Create multiple section faces

  • This option allows user to create multiple section faces above or below the plane defined in the bolt bodies.
  • This is supported only for the following cases.
    • Abaqus and OptiStruct solvers.
    • Pretension section should be created using plane definitions.
    • Bolt should be created using HEX elements.
    • Multiple sections can be created for single bolt only.

Cards supported for various solvers

Solver Supported Cards
OptiStruct PRETENSION (Subcase section)SURFPRETENSPTADDPTFORCEPTADJST
Abaqus *PRE-TENSION SECTION*CLoad*Boundary, Fixed
Ansys SECTYPE, PRETENSIONSLOADFD
ADVENTURECluster $LinearConstraint$LocalCoordinateSystem$DisplacementLocalSystemID$Load$ForcedDisplacement
RADIOSS /PRELOAD & /SUBSET