Thank you so much David for your answer, that makes a lot of sense! Just to clarify, let's say I've turned off SMART and run multiple simulations and found that KI = KIC when some arbitrary value of stress is applied. In my quasi-static simulation with SMART activated, if I wanted to run my simulation for x number of seconds (during which time my stress is being applied linearly), I would want to make sure that at a time, t = x / (# of initial substeps), the critical stress will be applied within a few substeps ?
Again, thank you so much for your time!