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Hi i am performing Modal Frequency response analysis for motor assembly in optistruct but i am getting zero displacement values when giving unit excitation load. Please do the needful.
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Please try plotting curve using h3d file.
Thanks for your response sir. I am attaching my deck file, could you please check whether the load collectors are correct or not.
Unable to find an attachment - read this blog
Could you also share .out file of the run?
Yes sir
Replying to previous comment, there is no difference by plotting the curve using h3d file.
I guess the issue is with frequency range defined in Freq card and Tabled1.1st frequency of the assembly itself is 345hz and you are evaluating it for 100hz.
Actually the maximum speed of the motor is 3200rpm i.e., 53.33Hz . If we give the frequency range from 345Hz means it will be exceeding the maximum speed of the motor-pump assembly.
I am attaching the frequencies attained from Modal analysis.
Please do the needful.
Replying to the previous comment, after changing the frequency range to 0-1000 Hz the displacement is zero.
Hi,
you are getting zero displacements because the output set contains 8 nodes constrained by SPC in all DOF. Only unconstrained nodes should have non-zero displacements.