OS-V: 0700 Twisted Cantilever Beam (Implicit Results)

MacNeal-Harder Test This is a twisted cantilever beam solved with solid and shell elements. A model is made with each element's type to investigate the effect of distorted elements with a high aspect ratio.


veri_twist
Figure 1. FE Model of the Beam with Boundary Conditions and Loadcases

Benchmark Model

Six types of elements are used for this problem. They are tria-shell, quad-shell, and hexa-solid elements, each with 1st and 2nd order. Two loading cases are used for each model; in-plane bending, transverse bending. For both load cases, unit loads are applied in a consistent fashion over all of the nodes at the tip of the beam.

Theoretical solutions for the deflections at the tip, computed by beam theory are:
Load Type Component Value
In-plane bending UY 0.001754
Transverse bending UZ 0.005424

Linear Static Analysis Results

All results are normalized with the target value.
  In-plane Bending Transverse Bending
QUAD4 0.988 0.992
QUAD8 1.014 1.062
TRI3 0.839 0.984
TRI6 1.161 1.215
HEX8 0.986 1.005
HEX20 1.017 1.052

Model Files

The model files used in this problem include:

<install_directory>/hwsolvers/demos/optistruct/verification
  • /TBhex8.fem
  • /TBhex20.fem
  • /TBquad4.fem
  • /TBquad8.fem
  • /TBtri3.fem
  • /TBtri6.fem

Reference

MacNeal, R.H., and Harder, R.L., A Proposed Standard Set of Problems to Test Finite Element Accuracy, Finite Elements in Analysis and Design, 1 (1985) 3-20.