Norlizan - at a rate of 2mm/min a static analysis should be valid, so try it first. If you are performing a dynamic analysis, check to make sure the mass units are compatible with the dimensional, stiffness, damping (if included) and time units in the analysis.

If you've been performing a static analyses, check to make sure the time incrementing and convergence criteria specified are reasonable (also check the .msg file for solution residuals)

if the material model has rate dependency, then there's no surprise if you see difference in results with different rates. If it's not rate dependent, then something is going on in your analysis

There should be no difference unlesss:

1. You use rate-dependent material model (viscoelasticity or viscoplasticity)

2. You use damage model that use viscous regularization

3. You use damping to make your simulation converges.

Turn off all of those and you should have the same results.

Hi William, thank you for your feedback. I'm using second as my time unit in static analysis. So I've tried 1200s, 80s, 40s and 1s, all given a different results. I used automatic incrementation by assigning values for initial, minimum and maximum increment size that I think small enough for each time period. But I wasn't sure what is the range value of reasonable convergence criteria.

Currently I'm still working on the static analysis, but planning to do the dynamic analysis also. Do you have any recommendation of references that I can refer for the dynamic analysis on concrete structure?

Hi Abhimanyu, I use concrete damaged plasticity model for concrete and for steel I assign the elastic and plastic properties. I'm not using the strain rate dependent data for both materials. That's why I thought there's nothing wrong with the material properties. However thank you for your feedback.