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, I have read a lot of old discussion in the past weeks) and I need an help for a random vibration analysis with fatigue.<\/p>\nHi all, I’m Piergiorgio, an italian mechanical engineer that is starting to learn Ansys Workbench. I just registered on this forum (a nice forum , I have read a lot of old discussion in the past weeks) and I need an help for a random vibration analysis with fatigue.<\/p>\n
<\/p>\n
The steps I’ve followed are:<\/p>\n
<\/p>\n
– Define material properties, including Tensile Ultimate Strenght and Alternating Stress Mean Stress Curve.<\/p>\n
<\/p>\n
-Import the model, reducing all to mid plane surfaces<\/p>\n
<\/p>\n
-Meshing<\/p>\n
<\/p>\n
-Do a MODAL ANALISYS, not damped!<\/p>\n
<\/p>\n
-Do a RANDOM VIBRATION ANALYSIS, with constant damping ratio of 0,08. Number of modes to use: all. Output control>Calculate velocity and acceleration: yes.<\/p>\n
<\/p>\n
-I entered 3 PSD G Acceleration, because I’ve 16 hours PSD acceleration in x-axis, then 16 hours in y-axis, then 16 hours in z-axis.<\/p>\n
<\/p>\n
-In Solution>Fatigue Tools I’ve set: Method=Steinberg. Stress component=Von-Mises. Exposure duration=57600 s (because the sollecitation is for 16 hours in every direction)<\/p>\n
<\/p>\n
-To obtain the total fatigue damage, I entered a User Define Result with Expression=d1+d2+d3.<\/p>\n
<\/p>\n
Now, after all, I get and error: An error occurred inside the FATIGUE module: Invalid or missing stress life curve.<\/p>\n
<\/p>\n
But the curve is set with Alternating Stress Mean Stress Curve or Bilinear S-N curve (both in attachment). There is something I’m missing?<\/p>\n
<\/p>\n
NOTE: Modal and Random Vibration have the green mark. Solution have the red flash symbol.<\/p>\n
<\/p>\n
And another question: to find the fatigue damage, with the stress that I said before (16hr for every axis), the procedure is correct, using User Define Result d1+d2+d3?<\/p>\n
<\/p>\n
Sorry for this long post, but I’ve done a lot of try and nothing worked!<\/p>\n
<\/p>\n
Thanks in advance<\/p>\n
<\/p>\n
Piergiorgio<\/p>\n","protected":false},"template":"","class_list":["post-42076","topic","type-topic","status-closed","hentry"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_old_topic_id":["14256"],"_bbp_old_topic_author_name_id":["Anonymous"],"_bbp_old_is_topic_anonymous_id":["false"],"_bbp_old_closed_status_id":["publish"],"_bbp_author_ip":[null],"_bbp_old_sticky_status_id":["normal"],"_bbp_likes_count":["0"],"_btv_view_count":["4183"],"_bbp_subscription":["248937"],"_bbp_topic_status":["unanswered"],"_bbp_status":["publish"],"_bbp_topic_id":["42076"],"_bbp_forum_id":["27791"],"_bbp_engagement":["22","240","174728"],"_bbp_voice_count":["3"],"_bbp_reply_count":["4"],"_bbp_last_reply_id":["109154"],"_bbp_last_active_id":["109154"],"_bbp_last_active_time":["2020-03-27 12:46:23"]},"test":"pierj88"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/42076","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\/42076\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=42076"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}