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ABAQUS/Explicit: maximum initial strain-rate where Smooth step (Amplitude) is applicable?

ABAQUS/Explicit: maximum initial strain-rate where Smooth step (Amplitude) is applicable?

ABAQUS/Explicit: maximum initial strain-rate where Smooth step (Amplitude) is applicable?

(OP)
Smooth step (Amplitude) is helpful in avoiding excessive distortion at the beginning of the analysis, but I was wondering what is the maximum initial strain-rate we can use it? Say for example, in quasi-static the strain rate is 10-4 s-1 and Smooth step gives a better result than Ramp loading. So what is the upward limit of strain-rate that we can use the Smooth step, 1 s-1? 10 s-1? or 100 s-1??

RE: ABAQUS/Explicit: maximum initial strain-rate where Smooth step (Amplitude) is applicable?

There is no general answer - that's model dependent.

RE: ABAQUS/Explicit: maximum initial strain-rate where Smooth step (Amplitude) is applicable?

(OP)
Should not the loading be instantaneous for impact loading? I just want to make sure up to which strain-rate I can use Smooth step.

RE: ABAQUS/Explicit: maximum initial strain-rate where Smooth step (Amplitude) is applicable?

(OP)
@IceBreakerSours, is there any way to measure artificially induced inertia? And is there any suggested guideline/limit?

RE: ABAQUS/Explicit: maximum initial strain-rate where Smooth step (Amplitude) is applicable?

check the energy history for your analysis.

for a quasi-static explicit analysis, kinetic energy should be a small percentage of internal energy.

these slides might be helpful:
http://imechanica.org/files/l5-quasi-static.pdf

RE: ABAQUS/Explicit: maximum initial strain-rate where Smooth step (Amplitude) is applicable?

Unless I am missing something, aren't you simply going from F1=m*a_original to F2=m*a_artificial? You just monitor inertial energies or plot the second derivative of a nodal x/y/z displacement or something like that.

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RE: ABAQUS/Explicit: maximum initial strain-rate where Smooth step (Amplitude) is applicable?

(OP)
@Dave442, Thanks for the tip, I always follow this rule while doing quasi-static analysis in ABAQUS/Explicit.

In the experiment I am applying loading as "linear ramp", but in the simulation I am defining loading as "Smooth step". While in quasi-static strain-rate (10-4 s-1) this is not something important, my concern is that at high strain-rates (strain rate >1 s-1) the difference becomes something problematic?

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