Learning Forum

[franciscoperezsmith]

Hi all,

I have run two separate harmonic response analyses - one without the constraints added to it (as per tutorial videos and literature) and one with the constraints added. The two result sets I received were different!

With harmonic response analysis, what is best practice? To add the constraints, or leave them out?

Thank you for your help!

Francisco

[peteroznewman]

nHi Francisco,nYou have done a Full Harmonic Response. That means you must put the Fixed Support in the Harmonic Response to make it the same as the Modal.nIf you leave out the Fixed Support in the Harmonic Response then leave it out in the Modal to make them similar.nIf you create a link from the Solution cell of the Modal analysis to the Setup cell of the Harmonic Response (drag and drop), then you have specified a MSUP Harmonic Response. In a MSUP Harmonic Response, you don't add a Fixed Support in the Harmonic Response because it uses the solution from the Modal, so you can't change constraints, you can only add loads. If you change the constraints in the Modal, those get passed on to the linked Harmonic Response.n

[franciscoperezsmith]

Hi Peter,nThank you for your answer!nI can see where I went wrong; I forgot to instruct the Harmonic Analyses to use the results from the Modal Analysis (see image).nI was a fool! Thank you for your help.nHave a great Sunday,nFrancisconn