{"id":357970,"date":"2024-03-19T16:44:08","date_gmt":"2024-03-19T16:44:08","guid":{"rendered":"\/forum\/forums\/reply\/357970\/"},"modified":"2024-03-19T16:44:08","modified_gmt":"2024-03-19T16:44:08","slug":"357970","status":"publish","type":"reply","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/reply\/357970\/","title":{"rendered":"Reply To: Fatigue Analysis of Preload + Cyclic Loading"},"content":{"rendered":"<p>&lt;p class=&#8221;MsoNormal&#8221;&gt;The Mechanical Fatigue Tool (FT) can assess the fatigue behavior of a combined static load (e.g., preload) and alternating load (e.g., cyclic load).&lt;span style=&#8221;mso-spacerun: yes;&#8221;&gt;&nbsp; &lt;\/span&gt;The static load creates a mean stress.&lt;span style=&#8221;mso-spacerun: yes;&#8221;&gt;&nbsp; &lt;\/span&gt;Per the FT, this type of loading is known as constant amplitude, non-proportional loading and can be assessed by inserting a FT under a Solution Combination.&lt;\/p&gt;&lt;p class=&#8221;MsoNormal&#8221;&gt;For constant amplitude, non-proportional loading, the FT calculates the alternating stress as one-half of the difference between the two result sets in the Solution Combination (Salt = 0.5*(E1 &#8211; E2)), and the mean stress as the average of the two result sets (Smean = 0.5*(E1 + E2)).&lt;span style=&#8221;mso-spacerun: yes;&#8221;&gt;&nbsp; &lt;\/span&gt;To produce accurate fatigue results, you need to define the loading for the two result sets to ensure that the Solution Combination produces the correct alternating and mean stresses.&lt;span style=&#8221;mso-spacerun: yes;&#8221;&gt;&nbsp; &lt;\/span&gt;For example, if your two loading Environments are:&lt;\/p&gt;&lt;p class=&#8221;MsoNormal&#8221; style=&#8221;margin-bottom: 0in;&#8221;&gt;Environment 1 (E1) = static load + alternating load&lt;\/p&gt;&lt;p class=&#8221;MsoNormal&#8221; style=&#8221;margin-bottom: 0in;&#8221;&gt;Environment 2 (E2) = static load &#8211; alternating load&lt;\/p&gt;&lt;p class=&#8221;MsoNormal&#8221;&gt;The Solution Combination will produce:&lt;\/p&gt;&lt;p class=&#8221;MsoNormal&#8221; style=&#8221;margin-bottom: 0in;&#8221;&gt;Smean = &frac12;* (E1 + E2) = &frac12;* [ (static load + alternating load) + (static load &#8211; alternating load) ]&lt;\/p&gt;&lt;p class=&#8221;MsoNormal&#8221; style=&#8221;margin-bottom: 0in;&#8221;&gt;Smean = static load&lt;\/p&gt;&lt;p class=&#8221;MsoNormal&#8221; style=&#8221;margin-bottom: 0in;&#8221;&gt;and&lt;\/p&gt;&lt;p class=&#8221;MsoNormal&#8221; style=&#8221;margin-bottom: 0in;&#8221;&gt;Salt = &frac12;*(E1 &#8211; E2) = &frac12;* [ (static load + alternating load) &#8211; (static load &#8211; alternating load) ]&lt;\/p&gt;&lt;p class=&#8221;MsoNormal&#8221; style=&#8221;margin-bottom: 0in;&#8221;&gt;Salt = alternating load&lt;\/p&gt;<\/p>\n","protected":false},"template":"","class_list":["post-357970","reply","type-reply","status-publish","hentry"],"aioseo_notices":[],"acf":[],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/replies\/357970","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/replies"}],"about":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/types\/reply"}],"version-history":[{"count":0,"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/replies\/357970\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=357970"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}