Element nodal forces in beam section orientation

This problem contains basic test cases for one or more Abaqus elements and features.

This page discusses:

ProductsAbaqus/Standard

Elements tested

  • B21
  • B22
  • B23
  • B31
  • B32
  • B33

Features tested

Output variable NFORCSO gives the element nodal forces caused by stress in the element in the same coordinate system used to output section forces and moments. NFORCSO differs from NFORC only in the coordinate system used for output: NFORCSO components are the internal forces in the beam coordinate system, while NFORC components are internal forces in the global coordinate system.

Problem description

An L-shaped cantilever beam has concentrated loads applied at its free end. The length of each segment is 10 in., and the beam has a square cross-section with 0.10 in. sides. Steel elastic material properties are used (Young's modulus of 30 × 106 psi and Poisson's ratio of 0.3). Since the beam is slender, we choose to have the slenderness correction coefficient (SCF) computed from the elastic material definition; by adding the label SCF in the transverse shear stiffness definition, we obtain improved results with the linear Timoshenko beam elements B21 and B31.

Results and discussion

The results illustrate how the variable NFORCSO provides a more convenient way of examining results along beams, especially the case in long linear Timoshenko beam elements, since these elements possess a single integration point along the length of the beam. Output variable NFORCSO provides the bending moments at the extremities of the element, thus depicting the linearly varying bending moment distributions in the problem at hand. In quadratic Timoshenko beam elements B22 and B32 all NFORCSO components vanish at the center nodes as expected.