Direct cyclic step in ABAQUS

[PSRani]

Hi.. I have created an ABAQUS model with viscoelastic material to understand its creep or deformation characteristics. In which, the material is subjected to 10,000 cycles of repetitive loading (0.1s loading, 0.9s unloading: Total 1sec in 1 cycle) as attached herewith. To simulate this, I have used direct cyclic step, with loading cycle using tabular data as attached (for 1sec, 1cycle). But my doubt is I have 10,000 cycles (10,000 sec), so should I need to give the amplitude loading corresponding to 10,000 sec in tabular data?? That would be more cumbersome, so is there a way to give the amplitude loading for one cycle using tabular data but I wanted to say to the model to apply this amplitude loading repetitively for 10,000 times/10,000sec? Please note that, after each cycle the strains should be accumulated from each step. Any inputs in this regard will be appreciated.

 

[FEA way]

When you define an amplitude for the direct cyclic step, it only has to cover one cycle:

During the analysis each load must have an amplitude definition that is cyclic over the step where the start value must be equal to the end value.

 

[PSRani]

I have defined the amplitude to cover one cycle in direct cycle step, but my requirement is I need this cycle of load to be repeated for 10,000 cycles.So , Is there a way to define, repeat this load for 10,000 cycles

 

[FEA way]

If you want to perform a low-cycle fatigue analysis using the direct cyclic approach then you can specify the maximum number of cycles. In Abaqus/CAE, it's in the Fatigue tab when defining a direct cyclic step.

 

[PSRani]

1. I am applying a dynamic creep load on the material, and I am interested in understanding the creep response of the material. I have tried specifying the number of cycles in the low-cyclic fatigue analysis, but I have observed that strains are not accumulating with increase in number of cycles. Can't we use this direct cyclic step to perform the repeated dynamic creep load on the material so that I can understand the cumulative strains or deformations with increasing load cycles?


2. I have also tried using dynamic explicit, but I have found a keyword error after submitting the job. (THIS KEYWORD IS NOT AVAILABLE IN DYNAMIC EXPLICIT)

3. I have tried general static step for two cycles but the strains are not being cumulative at the end of loading. The deformation at the end of second cycle is exactly same as at the end of first cycle

4. Is there any other step using which, I wanted to apply the load with the amplitude as attached above, repetitively for 10,000 cycles. I also wanted to extract to cumulative strains or deformations with increase in number of cycles.

The material I am using is asphalt(Viscoelastic), I am giving creep properties as input from the dynamic creep experiment.