Beam

A Beam is a 1D element with six degrees of freedom per node, where the shear center can be offset. It has the options to use Property Input, Cross Section, or Structural Member under Input Type. See the Line Element Properties page for more information on the Input Types and associated settings.

• NSM: Defines non-structural mass for this element type.
• Preload: A preload value can be input on the Beam element. Used for modeling connections that have preload.
• Offset To: Options include Centroid (the default), Shear Center, Reference Point, and Origin. These options refer to the actual mesh (numerical representation) of the model.
  • Centroid: Will always mesh to the centroid of the library part used no matter how it looks on the screen.
  • Shear Center: Will mesh the selected structural members to the offset shear center.
  • Reference Point: Used for cross section definition. A reference point can be assigned to a location on the cross section and then the section offset to this reference point location.
  • Origin: Will mesh the selected structural members to the offset origin of the library file used. Used only for Structural Members.
• Offset vectors are treated like rigid elements and are therefore subject to the same limitations.
  • Offset vectors do not affect thermal loads.
  • The specification of offset vectors is not recommended in solutions that compute differential stiffness because the offset vector remains parallel to its original orientation (differential stiffness is computed in buckling, prestress, and nonlinear analysis with large displacement effects ON).
  • The following figure defines beam element geometry:

    

    Beam Element Geometry System

    

    Beam Internal Element Forces and Moments

    

    Beam Element Internal Forces and Moments (xy-Plane)

    

    Beam Element Internal Forces and Moments (xz-Plane)