Product: ABAQUS/Standard
This problem verifies and illustrates the use of axisymmetric solid elements with twist in ABAQUS. An Airy stress function provided by Fung (1977) is used to obtain the stress components in the cylindrical coordinate system for this problem.
The physical problem consists of a hollow cylinder fixed at one end in the translational degrees of freedom. Opposing twists, equal in magnitude, are applied to the inner and outer diameters of the hollow cylinder. Figure 2.1.11 shows the model geometry used in this analysis. Most of the meshes used for this problem are uniform; however, since the stresses are a quadratic function of the radius, mesh refinement in regions of high strain gradients is suggested. Two input files have refined meshes near the inner diameter of the hollow cylinder with appropriate mesh refinement *MPCs. Some input files use the *COUPLING and *KINEMATIC COUPLING options to couple the boundary surfaces to reference nodes; the twists are applied to the reference nodes. All axisymmetric solid elements with twist are tested in this problem; coupled temperature-displacement elements are tested in a *COUPLED TEMPERATURE-DISPLACEMENT, STEADY STATE step with arbitrarily applied boundary temperatures and a coefficient of thermal expansion, 0, to prevent coupling with the mechanical solution. Mesh convergence studies have not been performed. To test the use of substructures in problems involving axisymmetric elements with twist, the problem is also solved using substructuring with the entire model treated as a single substructure.
The derived analytical solution for this problem, based on an Airy stress function provided by Fung (1977), is
Figure 2.1.12 shows the variation of the shear stress, , with respect to the radius of the hollow cylinder for the CGAX8 element model (where S13) compared to the analytical solution. The results for all elements agree well with the analytical solution. The results from the substructure analysis match the results that are obtained when substructures are not used.
CGAX3 model using the *COUPLING and *KINEMATIC options to impose the twist.
CGAX3 model using the *KINEMATIC COUPLING option to impose the twist.
CGAX3H model.
CGAX4 model.
CGAX4H model.
CGAX4HT model.
CGAX4R model with mesh refinement.
CGAX4RH model.
CGAX4RH model with enhanced hourglass control.
CGAX4T model.
CGAX6 model.
CGAX6H model.
CGAX6M model.
CGAX6MH model.
CGAX8 model.
CGAX8 model using substructuring.
Substructure generation referenced in the analysis torsholcyl_cgax8_substruct.inp.
CGAX8H model.
CGAX8H model with a neo-Hookean incompressible hyperelastic material.
CGAX8HT model.
CGAX8R model with mesh refinement.
CGAX8RH model.
CGAX8RHT model.
CGAX8RT model.
CGAX8T model.