Hello,

I'm using ATENA to model a beam-column sub-assembly under quasi-static cyclic loading. Thus far I've been using monotonic forced displacement applied to the top of the column just to get a feel for the analysis and the step size I need to use. Having determined that a step size of around 0.25mm seems to provide adequate results, I'm now trying to determine the best way to input a cyclic load history.

Because the increments need to be so small to achieve proper convergence and accuracy, it seems like a very large number of steps would be required. Each cycle would need to rise and fall in 0.25mm increments, correct? So the load steps might look something like (0.25,0.25,-0.25,-0.25,-0.25,-0.25...), in order to increase the forced displacement to the required amplitude then reduce back to zero, then increase to the amplitude in the opposite direction. Am I interpreting this correctly?

Given that this would generate a large amount of steps that I would need to input manually, managing all this within ATENA seems extremely cumbersome. Is there an easy way to do this within ATENA that I'm missing? Failing that, is there a way to import an Excel spreadsheet (or a text file) of a load history?

Thanks.