{"id":36835,"date":"2019-07-29T21:16:37","date_gmt":"2019-07-29T21:16:37","guid":{"rendered":"\/forum\/forums\/topic\/modal-analysis-boundary-condition-problem\/"},"modified":"2019-07-29T21:16:37","modified_gmt":"2019-07-29T21:16:37","slug":"modal-analysis-boundary-condition-problem","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/modal-analysis-boundary-condition-problem\/","title":{"rendered":"Modal analysis (boundary condition problem)"},"content":{"rendered":"<p>Hi All,<\/p>\n<p><\/p>\n<p>Hope you are well<\/p>\n<p><\/p>\n<p>I am using Workbench to get the natural frequencies for the rail as is it shown in the below screenshot<\/p>\n<p><\/p>\n<p>I have tested the rail in Free-Free boundary&nbsp;condition in the lab&nbsp;where it is supported by foam and modelled it in Ansys workbench in Free-Free condition (without any restrictions on the boundary condition) and&nbsp;I&nbsp;got&nbsp;similar result with&nbsp;error&nbsp;percentage&nbsp;(difference) from 1% to 4% for the first 5 modes . when I modelled the rail where it is placed on hard wood sleepers (where it is placed in the lab, second boundary condition) the model result are completely different from the experiment result.<\/p>\n<p><\/p>\n<p>Can any one please help me&nbsp;wither is my boundary condition in Ansys is wrong or there is a problem in my contact (connection between the rail and the sleepers).<\/p>\n<p><\/p>\n<p>&nbsp;<\/p>\n<p><\/p>\n<p>&nbsp;<\/p>\n<p><\/p>\n<p><img decoding=\"async\" src=\"https:\/\/us.v-cdn.net\/6032193\/uploads\/attachments\/224e4c95-95b9-41ce-9581-aa9901451288\/f23e28c0-5050-473d-a98f-aa99015e7f6c_connection.jpg?width=690&amp;upscale=false\" alt=\"\"><img decoding=\"async\" src=\"https:\/\/us.v-cdn.net\/6032193\/uploads\/attachments\/224e4c95-95b9-41ce-9581-aa9901451288\/e544e1a4-def7-4915-b5f4-aa99015e8e3f_mode.jpg?width=690&amp;upscale=false\" alt=\"\"><img decoding=\"async\" src=\"https:\/\/us.v-cdn.net\/6032193\/uploads\/attachments\/224e4c95-95b9-41ce-9581-aa9901451288\/b989244e-b077-4596-98e6-aa99015e9b2a_fixed-supports.jpg?width=690&amp;upscale=false\" alt=\"\"><\/p>\n<p><\/p>\n<p>current Boundary condition : Fixed support<\/p>\n","protected":false},"template":"","class_list":["post-36835","topic","type-topic","status-closed","hentry"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_old_topic_id":["9009"],"_bbp_old_topic_author_name_id":["Anonymous"],"_bbp_old_is_topic_anonymous_id":["false"],"_bbp_old_closed_status_id":["publish"],"_bbp_author_ip":[null],"_bbp_old_sticky_status_id":["normal"],"_bbp_likes_count":["0","0"],"_btv_view_count":["3700"],"_bbp_topic_status":["unanswered"],"_bbp_status":["publish"],"_bbp_topic_id":["36835"],"_bbp_forum_id":["27791"],"_bbp_engagement":["22","240","167197"],"_bbp_voice_count":["3"],"_bbp_reply_count":["18"],"_bbp_last_reply_id":["91248"],"_bbp_last_active_id":["91248"],"_bbp_last_active_time":["2019-08-04 18:51:42"]},"test":"abdulahalmutairi"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/36835","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\/36835\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=36835"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}