PARAM, FLLWER

Bulk Data Entry Calculation of follower forces introduced by pressure loads and concentrated forces in large displacement nonlinear analysis.

Attention: Valid for Implicit and Explicit Analysis
Parameter Values Description
FLLWER <-1, 0, 1, 2, 3>

Default = 1 (for pressure loads)

Default = 0 (for concentrated loads)

 For a time-dependent dynamic load, it controls the follower force option for the amplitude of the dynamic excitation defined by pressure loads and concentrated loads. 1
= -1 or 0
Follower force calculation is deactivated.
= 1
Follower effect is enabled.
For pressure load, both the changes of element surface area and the direction of the load are involved to calculate the follower force.
For concentrated force, only the force direction is involved.
= 2
Follower effect is enabled.
For pressure load, only the change of element surface area is involved to calculate the follower force.
For concentrated force, only the force direction is involved (same effect as FLLWER = 1).
= 3
Follower effect is enabled.
For pressure load, only the change of load direction is involved to calculate the follower force.
For concentrated force, only the force direction is involved (same effect as FLLWER = 1).

Comments

  1. Supported load types are:
    Pressure load
    PLOAD, PLOAD2, PLOAD4, PLOADSF, PLOADE1, PLOADX1 and PRSPENE
    Concentrated load
    FORCE, FORCE1, FORCE2, MOMENT, MOMENT1, and MOMENT2
  2. The follower effects of FORCE1, FORCE2, MOMENT1, and MOMENT2 are based on the vectors formed by the user-specified nodes, while that of FORCE/MOMENT is based on the rotation of the nodes.
  3. To activate the follower effect for FORCE/MOMENT, an additional flag, ROT is required. For more details, refer to the FORCE/MOMENT Bulk Data Entries.
  4. In case of Nonlinear Explicit Analysis (NLEXPL), follower loads are supported with DLOAD/TLOAD#, for all supported pressure loads, FORCE1, FORCE2, MOMENT1 and MOMENT2.