topic Maximum absolute value of the principal structural strains in Inventor Nastran Forum https://forums.autodesk.com/t5/inventor-nastran-forum/maximum-absolute-value-of-the-principal-structural-strains/m-p/8607530#M9961 <P>Hello!</P> <P>&nbsp;</P> <P>I need to evaluate according to PED (Pressure directive),</P> <P>&nbsp;</P> <P>it states max 5% "maximum absolute value of the principal structural strains"</P> <P>&nbsp;</P> <P>Can i see that in nastran in cad? what is it called?</P> <P>&nbsp;</P> <P>&nbsp;</P> Wed, 20 Feb 2019 06:18:17 GMT martin.alvin 2019-02-20T06:18:17Z Maximum absolute value of the principal structural strains https://forums.autodesk.com/t5/inventor-nastran-forum/maximum-absolute-value-of-the-principal-structural-strains/m-p/8607530#M9961 <P>Hello!</P> <P>&nbsp;</P> <P>I need to evaluate according to PED (Pressure directive),</P> <P>&nbsp;</P> <P>it states max 5% "maximum absolute value of the principal structural strains"</P> <P>&nbsp;</P> <P>Can i see that in nastran in cad? what is it called?</P> <P>&nbsp;</P> <P>&nbsp;</P> Wed, 20 Feb 2019 06:18:17 GMT https://forums.autodesk.com/t5/inventor-nastran-forum/maximum-absolute-value-of-the-principal-structural-strains/m-p/8607530#M9961 martin.alvin 2019-02-20T06:18:17Z Re: Maximum absolute value of the principal structural strains https://forums.autodesk.com/t5/inventor-nastran-forum/maximum-absolute-value-of-the-principal-structural-strains/m-p/8608932#M9962 <P>Hi&nbsp;<a href="https://forums.autodesk.com/t5/user/viewprofilepage/user-id/6870858">@martin.alvin</a>&nbsp;</P> <P>&nbsp;</P> <P>I think they are indicating that you need to use the principal strain. In particular, if the part is in compression, then the&nbsp; minimum principal strain will be a larger absolute value than the maximum principal strain, so you want to use&nbsp; the minimum principal strain value.</P> <P>&nbsp;</P> <P>The strain can be output by Nastran, but you may need to edit the analysis settings first and check the box to output the strain result.</P> <P><span class="lia-inline-image-display-wrapper lia-image-align-inline" image-alt="analysis settings.png" style="width: 380px;"><img src="https://forums.autodesk.com/t5/image/serverpage/image-id/605312i03E1191685658FC3/image-size/large?v=v2&amp;px=999" role="button" title="analysis settings.png" alt="analysis settings.png" /></span></P> Wed, 20 Feb 2019 16:36:08 GMT https://forums.autodesk.com/t5/inventor-nastran-forum/maximum-absolute-value-of-the-principal-structural-strains/m-p/8608932#M9962 John_Holtz 2019-02-20T16:36:08Z