{"id":163122,"date":"2021-10-15T19:12:41","date_gmt":"2021-10-15T19:12:41","guid":{"rendered":"\/forum\/forums\/topic\/why-does-modal-analysis-repeat-each-natural-frequency\/"},"modified":"2021-11-01T21:35:52","modified_gmt":"2021-11-01T21:35:52","slug":"why-does-modal-analysis-repeat-each-natural-frequency","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/why-does-modal-analysis-repeat-each-natural-frequency\/","title":{"rendered":"Why does modal analysis repeat each natural frequency?"},"content":{"rendered":"
\n
\n

Hi,<\/p>\n

The following macro is for a cantilever beam and I was wondering why the frequencies are repeated in the results?<\/p>\n

<\/p>\n<\/p>\n

\/PREP7  <\/p>\n

<\/p>\n<\/p>\n

ET,1,BEAM188<\/p>\n

<\/p>\n<\/p>\n

MPTEMP,,,,,,,,  <\/p>\n

MPTEMP,1,0  <\/p>\n

MPDATA,EX,1,,2.068e11  <\/p>\n

MPDATA,PRXY,1,,0.3  <\/p>\n

MPTEMP,,,,,,,,  <\/p>\n

MPTEMP,1,0  <\/p>\n

MPDATA,DENS,1,,7830 <\/p>\n

SECTYPE,  1, BEAM, RECT, Beam01, 0 <\/p>\n

SECOFFSET, CENT <\/p>\n

SECDATA,0.01,0.01,2,2,0,0,0,0,0,0,0,0  <\/p>\n

K,1,0,0,0,  <\/p>\n

K,2,1,0,0,  <\/p>\n

LSTR,    1,    2  <\/p>\n

<\/p>\n<\/p>\n

LESIZE,ALL, , ,8, ,1, , ,1, <\/p>\n

LMESH,    1  <\/p>\n

FINISH  <\/p>\n

\/SOL<\/p>\n

<\/p>\n<\/p>\n

ANTYPE,2<\/p>\n

<\/p>\n<\/p>\n

MODOPT,LANB,8  <\/p>\n

EQSLV,SPAR  <\/p>\n

MXPAND,8, , ,0  <\/p>\n

LUMPM,0 <\/p>\n

PSTRES,0<\/p>\n

<\/p>\n<\/p>\n

MODOPT,LANB,8,0,0, ,OFF <\/p>\n

FLST,2,1,1,ORDE,1  <\/p>\n

FITEM,2,1  <\/p>\n

 <\/p>\n

\/GO <\/p>\n

D,P51X, , , , , ,ALL, , , , ,  <\/p>\n

\/STATUS,SOLU<\/p>\n

SOLVE  <\/p>\n

<\/p>\n<\/p>\n

The results are as follows:<\/strong><\/p>\n

<\/p>\n<\/p>\n

 ***** INDEX OF DATA SETS ON RESULTS FILE *****<\/p>\n

<\/p>\n<\/p>\n

  SET  TIME\/FREQ  LOAD STEP  SUBSTEP CUMULATIVE<\/p>\n

   1 8.3119 <\/strong>      1     1     1          <\/p>\n

   2 8.3119<\/strong>       1     2     2          <\/p>\n

   3 53.804       <\/strong>1     3     3          <\/p>\n

   4 53.804       <\/strong>1     4     4          <\/p>\n

   5 160.84       <\/strong>1     5     5          <\/p>\n

   6 160.84       <\/strong>1     6     6          <\/p>\n

   7 349.86       <\/strong>1     7     7          <\/p>\n

   8 349.86       <\/strong>1     8     8  <\/p>\n","protected":false},"template":"","class_list":["post-163122","topic","type-topic","status-closed","hentry"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_author_ip":[""],"_bbp_old_reply_author_name_id":["Anonymous"],"_bbp_old_is_reply_anonymous_id":["false"],"_btv_view_count":["2201"],"_bbp_likes_count":["0"],"_bbp_subscription":["242505"],"_bbp_topic_status":["unanswered"],"_bbp_status":["publish"],"_bbp_topic_id":["163122"],"_bbp_forum_id":["27791"],"_bbp_engagement":["240","223563","237993"],"_bbp_voice_count":["3"],"_bbp_reply_count":["5"],"_bbp_last_reply_id":["194936"],"_bbp_last_active_id":["194936"],"_bbp_last_active_time":["2021-11-01 21:35:52"]},"test":"amk068usask-ca"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/163122","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\/163122\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=163122"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}