{"id":235317,"date":"2022-09-15T11:14:08","date_gmt":"2022-09-15T11:14:08","guid":{"rendered":"\/forum\/forums\/reply\/235317\/"},"modified":"2022-09-15T11:15:15","modified_gmt":"2022-09-15T11:15:15","slug":"235317","status":"publish","type":"reply","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/reply\/235317\/","title":{"rendered":"Reply To: Verification of repeated eigenfrequencies"},"content":{"rendered":"<p>&lt;p&gt;If the structure has two planes of symmetry (both geometric and boundary conditions), then you expect repeated eigenfrequencies because the structure will move in the XY plane for one and move in the YZ plane for the repeated frequency due to those being the planes of symmetry. If the structure, including the mesh, is not perfectly symmetric, then a small difference can be introduced between the two planes, but I would still call that a repeated eigenfrequency.&lt;\/p&gt;&lt;p&gt;It&rsquo;s possible to have two very close frequencies that have totally different mode shapes. You can see that when you animate the two modes. You can&rsquo;t tell from the values alone, you need to look at the mode shape.&lt;\/p&gt;<\/p>\n","protected":false},"template":"","class_list":["post-235317","reply","type-reply","status-publish","hentry"],"aioseo_notices":[],"aioseo_head":"\n\t\t<!-- All in One SEO 4.9.10 - aioseo.com -->\n\t<meta name=\"description\" content=\"If the structure has two planes of symmetry (both geometric and boundary conditions), then you expect repeated eigenfrequencies because the structure will move in the XY plane for one and move in the YZ plane for the repeated frequency due to those being the planes of symmetry. If the structure, including the mesh, is not\" \/>\n\t<meta name=\"robots\" content=\"max-image-preview:large\" \/>\n\t<link rel=\"canonical\" href=\"https:\/\/innovationspace.ansys.com\/forum\/forums\/reply\/235317\/\" \/>\n\t<meta name=\"generator\" content=\"All in One SEO (AIOSEO) 4.9.10\" \/>\n\t\t<meta property=\"og:locale\" content=\"en_US\" \/>\n\t\t<meta property=\"og:site_name\" content=\"Ansys Learning Forum | Ansys Innovation Space\" \/>\n\t\t<meta property=\"og:type\" content=\"article\" \/>\n\t\t<meta property=\"og:title\" content=\"Reply To: Verification of repeated eigenfrequencies | Ansys Learning Forum\" \/>\n\t\t<meta property=\"og:description\" content=\"If the structure has two planes of symmetry (both geometric and boundary conditions), then you expect repeated eigenfrequencies because the structure will move in the XY plane for one and move in the YZ plane for the repeated frequency due to those being the planes of symmetry. If the structure, including the mesh, is not\" \/>\n\t\t<meta property=\"og:url\" content=\"https:\/\/innovationspace.ansys.com\/forum\/forums\/reply\/235317\/\" \/>\n\t\t<meta property=\"article:published_time\" content=\"2022-09-15T11:14:08+00:00\" \/>\n\t\t<meta property=\"article:modified_time\" content=\"2022-09-15T11:15:15+00:00\" \/>\n\t\t<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n\t\t<meta name=\"twitter:title\" content=\"Reply To: Verification of repeated eigenfrequencies | Ansys Learning Forum\" \/>\n\t\t<meta name=\"twitter:description\" content=\"If the structure has two planes of symmetry (both geometric and boundary conditions), then you expect repeated eigenfrequencies because the structure will move in the XY plane for one and move in the YZ plane for the repeated frequency due to those being the planes of symmetry. 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