Product: ABAQUS/Standard
The tests in this section verify the direct cyclic analysis procedure for structures subjected to different types of cyclic loadings, which include distributed forces, concentrated forces, displacements, and temperatures. The direct cyclic procedure is also verified when it is preceded or followed by other procedures in a single analysis or in a restart analysis.
The model in each test consists of twelve tetrahedral elements or one brick element. All the nodes at one end (
) are constrained along the z-axis. Cyclic distributed loads, concentrated loads, or displacements are applied in the z-direction to the nodes at the other end (
). Both kinematic hardening plasticity models and two-layer viscoplasticity models are used.
The results obtained using the direct cyclic procedure are compared with those obtained using the classical approach, which involves applying cyclic loadings repetitively to the model in multiple steps using the *STATIC option or the *VISCO option. The shapes of the stress-strain curves in a stabilized cycle obtained using both approaches are consistent.
Cyclic concentrated loadings with fixed number of Fourier terms and fixed time incrementation.
Cyclic concentrated loadings with fixed number of Fourier terms and fixed time incrementation used with the *TIME POINTS option.
Cyclic concentrated loadings with varying number of Fourier terms and fixed time incrementation.
Cyclic concentrated loadings with varying number of Fourier terms and fixed time incrementation used with the *TIME POINTS option.
Cyclic concentrated loadings with fixed number of Fourier terms and automatic time incrementation used with the *TIME POINTS option.
Static pre-loading step.
Restart of dircyclic_precload.inp. Cyclic concentrated loadings with fixed number of Fourier terms and fixed time incrementation.
Restart of dircyclic_cload_ffouri_ftinc_r.inp. Cyclic concentrated loadings with fixed number of Fourier terms and fixed time incrementation.
Post output of dircyclic_cload_ffouri_ftinc_r.inp.
Multiple direct cyclic analysis steps in a single analysis. Cyclic concentrated loadings with fixed number of Fourier terms and fixed time incrementation.
Cyclic distributed loadings with fixed number of Fourier terms and fixed time incrementation.
Cyclic displacement loadings with fixed number of Fourier terms and fixed time incrementation.
A general static step with contact followed by a direct cyclic step involving cyclic concentrated loadings with varying number of Fourier terms and fixed time incrementation.
The undeformed square sheet is 1.5 mm thick and is 7.5 mm on each side. It has a centrally located internal hole of radius 0.25 mm. The body is modeled with 128 plane strain reduced-integration elements (element type CPE4R). The symmetry conditions at 
and at 
are imposed with the *BOUNDARY option. The edges parallel to the x-axis are restrained from stretching in the y-direction. Cyclic concentrated forces or cyclic distributed forces are imposed on the right-hand edge of the mesh in the x-direction. For the case where cyclic thermal loadings read from the results file of a heat transfer analysis are imposed, the right-hand edge is also constrained in the x-direction. Both kinematic hardening plasticity models and two-layer viscoplasticity models are used.
The results (stress-strain curves) obtained using the direct cyclic procedure are compared with those obtained using the classical approach, which involves applying cyclic loadings repetitively to the model in multiple steps using the *STATIC option or the *VISCO option. The shapes of the stress-strain curves in a stabilized cycle obtained using both approaches are consistent. In the case where cyclic concentrated forces are applied to the model, plastic ratcheting occurs in which the shape of the stress-strain curve does not change but the mean value of the strains keeps shifting. This behavior is predicted by using both the direct cyclic approach and the classical approach.
Heat transfer analysis.
Cyclic thermal loadings with temperatures read from the results file of the heat transfer run (dircyclic_heat.inp).
Cyclic thermal loadings with temperatures read from the results file of the heat transfer run (dircyclic_heat.inp) and ramped up to their initial condition values.
Cyclic distributed loadings with varying number of Fourier terms and fixed time incrementation.
Cyclic concentrated loadings with varying number of Fourier terms and automatic time incrementation used with the *TIME POINTS option.
Post output of dircyclic_cload_vfouri_vtinctp.inp.