{"id":382776,"date":"2024-09-16T14:12:46","date_gmt":"2024-09-16T14:12:46","guid":{"rendered":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/using-apdl-to-extract-stresses-on-a-beam-element\/"},"modified":"2024-09-16T14:12:46","modified_gmt":"2024-09-16T14:12:46","slug":"using-apdl-to-extract-stresses-on-a-beam-element","status":"publish","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/using-apdl-to-extract-stresses-on-a-beam-element\/","title":{"rendered":"Using APDL to extract stresses on a beam element."},"content":{"rendered":"

<p class=”MsoNormal”>I have been attempting to automate the extraction of principal stresses from a beam element model. This seems to be a little tricky, and I’m now having an issue exporting the principal stresses using APDL. I can see the principal stresses mapped onto the nodes in a stress plot, giving me an example maximum principal stress value here of 1.8e5 Pa. Using my APDL script, the principal stress I extract is 0.7e-30 Pa.<\/p><p class=”MsoNormal”>I have used this script successfully with shells and understand there is some difficulty in reading nodal stress outputs from beam elements. However, even in this model I have a maximum principal stress of 1.2e8 Pa on my shell node whereas the script picks up -0.2e-2 Pa. Stranger still, it reads the middle and minimum principal stresses fine for the shell.<\/p><p class=”MsoNormal”>Anyone know what the problem is here please? <\/p><p class=”MsoNormal”>I will include the script below for reference:<\/p><div>\/OUTRES,DATAFILE,TXT<\/div><div>FINISH<\/div><div>\/POST1<\/div><div>SET,LAST<\/div><div> <\/div><div>!   Name a text file and write headers for columns.<\/div><div>FNAME = ‘NodeStress'<\/div><div>*CFOPEN,%FNAME%,TXT<\/div><div>*VWRITE,’No.’,’MaxPrinc’,’MidPrinc’,’MinPrinc'<\/div><div>(A,’,’A,’,’A,’,’A)<\/div><div> <\/div><div>!   Select all nodes, and then call upon the node numbers we’re interested in. Name these using an<\/div><div>!   incremental value such that the names can be sequentially read. <\/div><div>ALLSEL<\/div><div>NS1 = 23<\/div><div>NS2 = 88<\/div><div>NS3 = 426<\/div><div> <\/div><div>Nos = 3<\/div><div> <\/div><div>!   ‘D’ is used as an integer describing the number of iterations performed.<\/div><div>D = 1<\/div><div> <\/div><div>!   Do loop for finding the node, getting the maximum\/middle\/minimum principal stresses.<\/div><div>*DO,A,1,Nos,1<\/div><div>NSEL,S,NODE,,NS%A%<\/div><div>*GET,Snom1%A%,NODE,NS%A%,S,1<\/div><div>*GET,Snom2%A%,NODE,NS%A%,S,2<\/div><div>*GET,Snom3%A%,NODE,NS%A%,S,3<\/div><div>ALLSEL<\/div><div> <\/div><div>!   Write the stress values to the text file.<\/div><div>*VWRITE,%D%,NS%A%,Snom1%A%,Snom2%A%,Snom3%A%<\/div><div>(F8.0,’,’F8.0,’,’E16.10,’,’E16.10,’,’E16.10)<\/div><div> <\/div><div>!   Increase the iteration count by one before restarting the loop.<\/div><div>D = D + 1<\/div><div> <\/div><div>*ENDDO<\/div><div> <\/div><div>!   Close the text file and end script.<\/div><div>\/OUTRES<\/div><div>*CFCLOSE\"\"<\/div><\/p>\n","protected":false},"template":"","class_list":["post-382776","topic","type-topic","status-publish","hentry","topic-tag-ansys-mechanical-apdl"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t