{"id":4768,"date":"2019-01-14T12:05:26","date_gmt":"2019-01-14T17:05:26","guid":{"rendered":"https:\/\/www.purdue.edu\/freeform\/ervibrations\/?page_id=4768"},"modified":"2019-01-14T12:16:42","modified_gmt":"2019-01-14T17:16:42","slug":"free-response-of-a-string","status":"publish","type":"page","link":"https:\/\/www.purdue.edu\/freeform\/ervibrations\/chapter-iii-animations\/free-response-of-a-string\/","title":{"rendered":"Free response of a string"},"content":{"rendered":"<p><!--This file created 9\/26\/02 6:04 PM by Claris Home Page version 3.0--><\/p>\n<p><em><span style=\"color: #000000; font-family: Arial; font-size: 14pt;\"><b>Response of string to initial deformation<\/b><\/span><\/em><\/p>\n<hr \/>\n<table style=\"width: 649px;\" border=\"1\" width=\"600\" cellpadding=\"6\">\n<tbody>\n<tr>\n<td style=\"vertical-align: top; width: 340.5625px;\">In this example we considered the free response of a fixed-fixed string to a set of initial conditions that resulted from pulling the string at its midpoint and releasing it from rest.<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/www.purdue.edu\/freeform\/ervibrations\/wp-content\/uploads\/sites\/18\/2019\/01\/string01.jpg\" \/><\/p>\n<p>We found that the response is a linear combination of the mode shapes (modal functions) as:<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/www.purdue.edu\/freeform\/ervibrations\/wp-content\/uploads\/sites\/18\/2019\/01\/string02.jpg\" \/><\/p>\n<p>where the response coefficients go as:<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/www.purdue.edu\/freeform\/ervibrations\/wp-content\/uploads\/sites\/18\/2019\/01\/string03.jpg\" \/><\/p>\n<p>That is, the contribution of the higher modes to the overall response drops at a rate of the square of the mode number.<\/p>\n<p>When twenty modes are included in the above summation, the response of the string is as shown in the response animation to the right (the Matlab code presented in the lecture notes was used to create this animation). Is this what you expected the response to look like?<\/p>\n<p>&nbsp;<\/td>\n<td style=\"width: 272.453125px; vertical-align: middle;\"><center><img loading=\"lazy\" decoding=\"async\" class=\"alignnone wp-image-4776\" src=\"https:\/\/www.purdue.edu\/freeform\/ervibrations\/wp-content\/uploads\/sites\/18\/2019\/01\/string.gif\" alt=\"\" width=\"267\" height=\"224\" \/><\/center><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n","protected":false},"excerpt":{"rendered":"<p>Response of string to initial deformation In this example we considered the free response of a fixed-fixed string to a set of initial conditions that resulted from pulling the string at its midpoint and releasing it from rest. We found that the response is a linear combination of the mode shapes (modal functions) as: where &hellip; <a href=\"https:\/\/www.purdue.edu\/freeform\/ervibrations\/chapter-iii-animations\/free-response-of-a-string\/\" class=\"more-link\">Continue reading <span class=\"screen-reader-text\">Free response of a string<\/span> <span class=\"meta-nav\">&rarr;<\/span><\/a><\/p>\n","protected":false},"author":10,"featured_media":0,"parent":4780,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"footnotes":""},"class_list":["post-4768","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.purdue.edu\/freeform\/ervibrations\/wp-json\/wp\/v2\/pages\/4768","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.purdue.edu\/freeform\/ervibrations\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/www.purdue.edu\/freeform\/ervibrations\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/www.purdue.edu\/freeform\/ervibrations\/wp-json\/wp\/v2\/users\/10"}],"replies":[{"embeddable":true,"href":"https:\/\/www.purdue.edu\/freeform\/ervibrations\/wp-json\/wp\/v2\/comments?post=4768"}],"version-history":[{"count":5,"href":"https:\/\/www.purdue.edu\/freeform\/ervibrations\/wp-json\/wp\/v2\/pages\/4768\/revisions"}],"predecessor-version":[{"id":4779,"href":"https:\/\/www.purdue.edu\/freeform\/ervibrations\/wp-json\/wp\/v2\/pages\/4768\/revisions\/4779"}],"up":[{"embeddable":true,"href":"https:\/\/www.purdue.edu\/freeform\/ervibrations\/wp-json\/wp\/v2\/pages\/4780"}],"wp:attachment":[{"href":"https:\/\/www.purdue.edu\/freeform\/ervibrations\/wp-json\/wp\/v2\/media?parent=4768"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}