{"id":281717,"date":"2023-04-30T12:33:44","date_gmt":"2023-04-30T12:33:44","guid":{"rendered":"\/forum\/?post_type=topic&p=281717"},"modified":"2023-04-30T12:33:44","modified_gmt":"2023-04-30T12:33:44","slug":"harmonic-analysis-how-to-accurately-collect-directional-frequency-response","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/harmonic-analysis-how-to-accurately-collect-directional-frequency-response\/","title":{"rendered":"Harmonic Analysis \u2013 how to accurately collect directional frequency response"},"content":{"rendered":"

Hi, i am trying to determine the frequency response in the Y- direction for three surfaces\/points.
1 at the contact between the two small accelerometers (left and right), and the top of this ‘dual rail magnet’, where another accelerometer sits (point mass A).<\/p>\n

this setup is trying to replicate what I have in a lab, where a vibration exciter is exciting the bottom of the ‘rod’ in the global Y-axis.<\/p>\n

<\/p>\n

It manages to read some resonance points for some mode shapes, but there are other mode shapes (such as ‘total deformation 8’) that the harmonic analysis frequency repsonse does not pick up.
The two small accelerometers would be experiencing signifcant resonance at this 8th natural frequency, as would the acceleromter mounted upon the large dual rail magnet, but this is not reflected at all in the hamonic response frequency plot.<\/p>\n

it is my belief that there should be a y-axis resonance here, but it appears not.<\/p>\n

i tried selecting different geometry, such as a node on the edge of the dual rail magnet cylinder, and set some to use “maximum” instead of average but no luck. in the simulation inside the modal analysis, i can see that the node i selected in moving in the Y- direction, as well as moving side to side in the x direction…<\/p>\n

<\/p>\n

I am not using MSUP due to the desire to model a damped system.<\/p>\n

the purpose of all of this is to try predict the response of various mounting methods upon curved sufaces, so this is my approximation of a magnet attached to the curved surface. another challenge i am having is that i can only model linear contacts using this analysis, but i do not have the computer power or patience to run through multiple different models with different mounting methods and a range of 10kHz all using transient analysis, so I am willing to take the loss on that front, i will report my challenges and essentially say “this was the best i could do”.<\/p>\n

I would appreciate any help anyone can provide. attached is my workbench file and the STEP file in this link
https:\/\/drive.google.com\/drive\/folders\/1jWcyWH52_lCRMEteTEcOPi9g9ChRnpR3?usp=sharing<\/p>\n

 <\/p>\n

Thank you,<\/p>\n

 <\/p>\n

Theo <\/p>\n

 <\/p>\n","protected":false},"template":"","class_list":["post-281717","topic","type-topic","status-closed","hentry"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_author_ip":["23.192.164.14"],"_bbp_subscription":["282121","240"],"_btv_view_count":["2453"],"_bbp_topic_status":["unanswered"],"_bbp_status":["publish"],"_bbp_topic_id":["281717"],"_bbp_forum_id":["27791"],"_bbp_engagement":["240","282121"],"_bbp_voice_count":["2"],"_bbp_reply_count":["5"],"_bbp_last_reply_id":["282441"],"_bbp_last_active_id":["282441"],"_bbp_last_active_time":["2023-05-04 20:32:05"]},"test":"19491101student-curtin-edu-au"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/281717","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics"}],"about":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/types\/topic"}],"version-history":[{"count":0,"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/281717\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=281717"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}