January 18, 2022 at 11:56 pmkimkarimi9574Subscriber
Does Anybody know how I can get the amplitude of vibration for each mode shape in a 3D problem in ANSYS modal?
Thanks in advance!January 19, 2022 at 9:37 amAkshay ManiyarAnsys EmployeeJanuary 19, 2022 at 1:26 pmkimkarimi9574SubscriberThank you very much for your answer! Which one of deformations (directional or total) is the amplitude?
January 19, 2022 at 2:41 pmAkshay ManiyarAnsys Employee
In aModal Analysis(and other eigenvalue-based analyses such as buckling), the solution consists of a deformed shape scaled by an arbitrary factor. The actual magnitudes of the deformations and any derived quantities, such as strains and stresses, are therefore meaningless. Displacements, stresses, strains, etc. reported with mode shapes are ÔÇ£relativeÔÇØ and do not reflect the actual magnitudes.
Can you explain what you want to calculate from modal analysis?
January 19, 2022 at 2:53 pmJanuary 19, 2022 at 4:39 pmAkshay ManiyarAnsys Employee
Why are you doing modal analysis? From the image you shared, I am not able to figure out it.
Amodal analysisdetermines the vibration characteristics (natural frequencies and mode shapes) of a structure or a machine component. It can also serve as a starting point for another, more detailed, dynamic analysis, such as a transient dynamic analysis, a harmonic analysis, or a spectrum analysis.
January 19, 2022 at 5:03 pmkimkarimi9574SubscriberJanuary 19, 2022 at 5:29 pmkimkarimi9574SubscriberThis is the paper
January 19, 2022 at 10:33 pmpeteroznewmanSubscriberHi A harmonic response analysis will compute the displacement amplitude of the pipe for a specific harmonic input. In Figure 5 shown above, the pinned supports have a lateral sinusoidal displacement amplitude of 0.012 m
January 20, 2022 at 1:50 amJanuary 20, 2022 at 8:14 amErik KostsonAnsys Employee
You just need to add the displacement there - so say 0.001 m in Y or whatever you have and that will be sinusoidal since it is a harmonic (sinusoidal loads/boundary conditions are assumed) analysis.
As a side and something that might be relevant.
If you are looking into the effect of the fluid conveyed in the pipe on the pipe vibration (Coriolis effect - so exerted pressure from fluid flow on the pipe wall during vibration), we need to use a coupled vibroacoustic analysis (Harmonic acoustic system with fluid as acoustic and pipe as structural region) with mean flow effect (convective acoustic equation is used with - see BF,,VMEN command for mean flow).
Not sure if this helps.
January 21, 2022 at 6:10 pmpeteroznewmanSubscriberthat's awesome!
February 2, 2022 at 4:43 pmkimkarimi9574SubscriberThanks a million, guys for your help! I could finally gain the correct answer, using your guidance. I appreciate it
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