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Frequency to Time FFT study results are not consistent with the Time domain results when External Strain node is used
Posted 10 avr. 2018, 19:47 UTC−4 Structural & Acoustics, Studies & Solvers, Structural Mechanics Version 5.3 0 Replies
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Hi.
I'm trying to obtain the time response of an elastic inclusion inside a visoelastic matrix when the inclusion is subject to sinusoidal time dependent inelastic-strain (Using "External Strain" node). I tried two approaches:
1- "Time dependent" study over a sufficient amount of time (4 times the biggest relaxtion time of the viscoelastic matrix). 2- "Frequency domain" study over a wide range of frequencies with an amplitude equal to the amplitude of the the actual actuation signal followed by a "Frequency to Time FFT" study (following a similar approach as the one in "Viscoelastic Structural Damper" tutorial)
However, the results of the two studies are totally different. Particularly, the time dependent response matches very well with the available analytical results for stresses and strains time histories but the inverse fft study results are totally off.
I have tried the same problem with the inclusion subject to a time dependent "body load" (instead of "external strain") and the results of the two approaches agree very well.
Does anyone have a solution or an advice for this problem?
-Thanks
Hello Mohammad Kazemi
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