{"id":169933,"date":"2022-05-30T15:55:10","date_gmt":"2022-05-30T15:55:10","guid":{"rendered":"\/forum\/forums\/topic\/degree-of-freedom-problem-in-calculating-stiffness-matrix-by-using-seopt-function\/"},"modified":"2022-06-01T09:40:47","modified_gmt":"2022-06-01T09:40:47","slug":"degree-of-freedom-problem-in-calculating-stiffness-matrix-by-using-seopt-function","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/degree-of-freedom-problem-in-calculating-stiffness-matrix-by-using-seopt-function\/","title":{"rendered":"Degree of Freedom problem in calculating stiffness matrix by using SEOPT function"},"content":{"rendered":"<p>I have a problem with calculating the stiffness matrix. Basically, I followed the instruction from the web, using the following codes, and have tried a relatively simple box design. In the end, I was able to get the matrix I needed.\u00a0<br \/>\nBut when it comes to my gearbox design, which is set 16 remote Points in the middle of the bearings and named in command, the same calculating way met some problems. Ansys reported the following error:<\/p>\n<p>No MASTER degrees of freedom are specified.\u00a0If the TOTAL command was used for automatic generation of MASTER degrees of freedom, it is invalid with the SPARSE solver in a substructure analysis.\u00a0Please use the M command to define at least one MASTER degree of freedom.<br \/>\nThis is a bit weird because as far as I know, I do use the M function in my code, which should specify the DOF. I expect a 96*96 stiffness matrix.<br \/>\nThere is my APDL code.<br \/>\nantype,substr<br \/>\nseopt,1,2,1,resolve <\/p>\n<p>*DIM,node_pos,array,arg1,4<br \/>\n*DIM,dof_text_col,CHAR,1,arg1*6<br \/>\n*GET,unitsys,ACTIVE,0,UNITS<\/p>\n<p>*DO,i,1,arg1<br \/>\n\u00a0M,M%i%,ALL<br \/>\n\u00a0node_pos(i,1)=i\u00a0\u00a0<br \/>\n\u00a0node_pos(i,2)=NX(M%i%)<br \/>\n\u00a0node_pos(i,3)=NY(M%i%)<br \/>\n\u00a0node_pos(i,4)=NZ(M%i%)<br \/>\n\u00a0dof_text_col(1,6*(i-1)+1)=&#8217;N%i%_DX&#8217;<br \/>\n\u00a0dof_text_col(1,6*(i-1)+2)=&#8217;N%i%_DY&#8217;<br \/>\n\u00a0dof_text_col(1,6*(i-1)+3)=&#8217;N%i%_DZ&#8217;<br \/>\n\u00a0dof_text_col(1,6*(i-1)+4)=&#8217;N%i%_RX&#8217;<br \/>\n\u00a0dof_text_col(1,6*(i-1)+5)=&#8217;N%i%_RY&#8217;<br \/>\n\u00a0dof_text_col(1,6*(i-1)+6)=&#8217;N%i%_RZ&#8217;<br \/>\n*ENDDO<\/p>\n<p>allsel,all<br \/>\nThanks a lot in advance!<\/p>\n","protected":false},"template":"","class_list":["post-169933","topic","type-topic","status-closed","hentry","topic-tag-degree-of-freedom-1","topic-tag-error","topic-tag-stiffness-matrix","topic-tag-substructuring-2"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_btv_view_count":["1937"],"_bbp_likes_count":["0"],"_bbp_subscription":["256645"],"_bbp_topic_status":["unanswered"],"_bbp_status":["publish"],"_bbp_topic_id":["169933"],"_bbp_forum_id":["27791"],"_bbp_engagement":["88","23687","256645"],"_bbp_voice_count":["3"],"_bbp_reply_count":["4"],"_bbp_last_reply_id":["215739"],"_bbp_last_active_id":["215739"],"_bbp_last_active_time":["2022-06-01 09:40:47"]},"test":"a380777747gmail-com"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/169933","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics"}],"about":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/types\/topic"}],"version-history":[{"count":0,"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/169933\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=169933"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}