{"id":162087,"date":"2023-01-25T07:34:17","date_gmt":"2023-01-25T07:34:17","guid":{"rendered":"\/knowledge\/forums\/topic\/how-does-ansys-fatigue-tool-calculate-the-alternating-stress-mean-stress-and-stress-ratio-for-non-proportional-loading\/"},"modified":"2023-07-31T12:36:23","modified_gmt":"2023-07-31T12:36:23","slug":"how-does-ansys-fatigue-tool-calculate-the-alternating-stress-mean-stress-and-stress-ratio-for-non-proportional-loading","status":"publish","type":"topic","link":"https:\/\/innovationspace.ansys.com\/knowledge\/forums\/topic\/how-does-ansys-fatigue-tool-calculate-the-alternating-stress-mean-stress-and-stress-ratio-for-non-proportional-loading\/","title":{"rendered":"How does ANSYS Fatigue Tool calculate the alternating stress, mean stress and stress ratio for non-proportional loading?"},"content":{"rendered":"<p>1. Calculate alternating and mean stress tensors. Each component of the alternating stress tensor is (max-min)\/2 and each component of the mean stress tensor is (max+min)\/2 from each analysis.  where &#8220;max&#8221; is the maximum component stress value at a point between the two analyses, and &#8220;min&#8221; the minimum component stress value at the same point between the two analyses.  2. Find the max principal stress from each stress tensor, an alternating one &#8220;alt&#8221; and a mean one &#8220;mean&#8221;.  3. Stress ratio R = (mean-alt)\/(mean+alt)  Note the stress ratio is calculated internally for the purpose of querying the SN curve for the material. The alternating and mean stresses described above are output under the fatigue tool under solution combination.  For more information on how to setup non-proportional loading see the training material for the Mechanical Fatigue Module.<\/p>\n","protected":false},"template":"","class_list":["post-162087","topic","type-topic","status-publish","hentry","topic-tag-alternating-stress","topic-tag-analysis-techniques","topic-tag-fatigue","topic-tag-mean-stress","topic-tag-mechanical","topic-tag-stress-ratio","topic-tag-structural-mechanics"],"aioseo_notices":[],"aioseo_head":"\n\t\t<!-- All in One SEO 4.9.10 - aioseo.com -->\n\t<meta name=\"description\" content=\"1. Calculate alternating and mean stress tensors. Each component of the alternating stress tensor is (max-min)\/2 and each component of the mean stress tensor is (max+min)\/2 from each analysis. where &quot;max&quot; is the maximum component stress value at a point between the two analyses, and &quot;min&quot; the minimum component stress value at the same point\" \/>\n\t<meta name=\"robots\" content=\"max-image-preview:large\" \/>\n\t<link rel=\"canonical\" href=\"https:\/\/innovationspace.ansys.com\/knowledge\/forums\/topic\/how-does-ansys-fatigue-tool-calculate-the-alternating-stress-mean-stress-and-stress-ratio-for-non-proportional-loading\/\" \/>\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 Knowledge | Ansys Innovation Space\" \/>\n\t\t<meta property=\"og:type\" content=\"article\" \/>\n\t\t<meta property=\"og:title\" content=\"How does ANSYS Fatigue Tool calculate the alternating stress, mean stress and stress ratio for non-proportional loading? | Ansys Knowledge\" \/>\n\t\t<meta property=\"og:description\" content=\"1. Calculate alternating and mean stress tensors. Each component of the alternating stress tensor is (max-min)\/2 and each component of the mean stress tensor is (max+min)\/2 from each analysis. where &quot;max&quot; is the maximum component stress value at a point between the two analyses, and &quot;min&quot; the minimum component stress value at the same point\" \/>\n\t\t<meta property=\"og:url\" content=\"https:\/\/innovationspace.ansys.com\/knowledge\/forums\/topic\/how-does-ansys-fatigue-tool-calculate-the-alternating-stress-mean-stress-and-stress-ratio-for-non-proportional-loading\/\" \/>\n\t\t<meta property=\"article:published_time\" content=\"2023-01-25T07:34:17+00:00\" \/>\n\t\t<meta property=\"article:modified_time\" content=\"2023-07-31T12:36:23+00:00\" \/>\n\t\t<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n\t\t<meta name=\"twitter:title\" content=\"How does ANSYS Fatigue Tool calculate the alternating stress, mean stress and stress ratio for non-proportional loading? | Ansys Knowledge\" \/>\n\t\t<meta name=\"twitter:description\" content=\"1. Calculate alternating and mean stress tensors. Each component of the alternating stress tensor is (max-min)\/2 and each component of the mean stress tensor is (max+min)\/2 from each analysis. where &quot;max&quot; is the maximum component stress value at a point between the two analyses, and &quot;min&quot; the minimum component stress value at the same point\" \/>\n\t\t<script type=\"application\/ld+json\" class=\"aioseo-schema\">\n\t\t\t{\"@context\":\"https:\\\/\\\/schema.org\",\"@graph\":[{\"@type\":\"BreadcrumbList\",\"@id\":\"https:\\\/\\\/innovationspace.ansys.com\\\/knowledge\\\/forums\\\/topic\\\/how-does-ansys-fatigue-tool-calculate-the-alternating-stress-mean-stress-and-stress-ratio-for-non-proportional-loading\\\/#breadcrumblist\",\"itemListElement\":[{\"@type\":\"ListItem\",\"@id\":\"https:\\\/\\\/innovationspace.ansys.com\\\/knowledge#listItem\",\"position\":1,\"name\":\"Home\",\"item\":\"https:\\\/\\\/innovationspace.ansys.com\\\/knowledge\",\"nextItem\":{\"@type\":\"ListItem\",\"@id\":\"https:\\\/\\\/innovationspace.ansys.com\\\/knowledge\\\/topics\\\/#listItem\",\"name\":\"Topics\"}},{\"@type\":\"ListItem\",\"@id\":\"https:\\\/\\\/innovationspace.ansys.com\\\/knowledge\\\/topics\\\/#listItem\",\"position\":2,\"name\":\"Topics\",\"item\":\"https:\\\/\\\/innovationspace.ansys.com\\\/knowledge\\\/topics\\\/\",\"nextItem\":{\"@type\":\"ListItem\",\"@id\":\"https:\\\/\\\/innovationspace.ansys.com\\\/knowledge\\\/forums\\\/topic-tag\\\/structural-mechanics\\\/#listItem\",\"name\":\"structural-mechanics\"},\"previousItem\":{\"@type\":\"ListItem\",\"@id\":\"https:\\\/\\\/innovationspace.ansys.com\\\/knowledge#listItem\",\"name\":\"Home\"}},{\"@type\":\"ListItem\",\"@id\":\"https:\\\/\\\/innovationspace.ansys.com\\\/knowledge\\\/forums\\\/topic-tag\\\/structural-mechanics\\\/#listItem\",\"position\":3,\"name\":\"structural-mechanics\",\"item\":\"https:\\\/\\\/innovationspace.ansys.com\\\/knowledge\\\/forums\\\/topic-tag\\\/structural-mechanics\\\/\",\"nextItem\":{\"@type\":\"ListItem\",\"@id\":\"https:\\\/\\\/innovationspace.ansys.com\\\/knowledge\\\/forums\\\/topic\\\/how-does-ansys-fatigue-tool-calculate-the-alternating-stress-mean-stress-and-stress-ratio-for-non-proportional-loading\\\/#listItem\",\"name\":\"How does ANSYS Fatigue Tool calculate the alternating stress, mean stress and stress ratio for non-proportional loading?\"},\"previousItem\":{\"@type\":\"ListItem\",\"@id\":\"https:\\\/\\\/innovationspace.ansys.com\\\/knowledge\\\/topics\\\/#listItem\",\"name\":\"Topics\"}},{\"@type\":\"ListItem\",\"@id\":\"https:\\\/\\\/innovationspace.ansys.com\\\/knowledge\\\/forums\\\/topic\\\/how-does-ansys-fatigue-tool-calculate-the-alternating-stress-mean-stress-and-stress-ratio-for-non-proportional-loading\\\/#listItem\",\"position\":4,\"name\":\"How does ANSYS Fatigue Tool calculate the alternating stress, mean stress and stress ratio for non-proportional loading?\",\"previousItem\":{\"@type\":\"ListItem\",\"@id\":\"https:\\\/\\\/innovationspace.ansys.com\\\/knowledge\\\/forums\\\/topic-tag\\\/structural-mechanics\\\/#listItem\",\"name\":\"structural-mechanics\"}}]},{\"@type\":\"Organization\",\"@id\":\"https:\\\/\\\/innovationspace.ansys.com\\\/knowledge\\\/#organization\",\"name\":\"Ansys Knowledge\",\"description\":\"Ansys Innovation Space\",\"url\":\"https:\\\/\\\/innovationspace.ansys.com\\\/knowledge\\\/\"},{\"@type\":\"WebPage\",\"@id\":\"https:\\\/\\\/innovationspace.ansys.com\\\/knowledge\\\/forums\\\/topic\\\/how-does-ansys-fatigue-tool-calculate-the-alternating-stress-mean-stress-and-stress-ratio-for-non-proportional-loading\\\/#webpage\",\"url\":\"https:\\\/\\\/innovationspace.ansys.com\\\/knowledge\\\/forums\\\/topic\\\/how-does-ansys-fatigue-tool-calculate-the-alternating-stress-mean-stress-and-stress-ratio-for-non-proportional-loading\\\/\",\"name\":\"How does ANSYS Fatigue Tool calculate the alternating stress, mean stress and stress ratio for non-proportional loading? | Ansys Knowledge\",\"description\":\"1. 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Calculate alternating and mean stress tensors. 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Calculate alternating and mean stress tensors. Each component of the alternating stress tensor is (max-min)\/2 and each component of the mean stress tensor is (max+min)\/2 from each analysis. where &quot;max&quot; is the maximum component stress value at a point between the two analyses, and &quot;min&quot; the minimum component stress value at the same point","og:url":"https:\/\/innovationspace.ansys.com\/knowledge\/forums\/topic\/how-does-ansys-fatigue-tool-calculate-the-alternating-stress-mean-stress-and-stress-ratio-for-non-proportional-loading\/","article:published_time":"2023-01-25T07:34:17+00:00","article:modified_time":"2023-07-31T12:36:23+00:00","twitter:card":"summary_large_image","twitter:title":"How does ANSYS Fatigue Tool calculate the alternating stress, mean stress and stress ratio for non-proportional loading? | Ansys Knowledge","twitter:description":"1. Calculate alternating and mean stress tensors. 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