{"id":403453,"date":"2025-01-03T22:30:51","date_gmt":"2025-01-03T22:30:51","guid":{"rendered":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/rigid-dynamics-forced-frictional-sliding-contact-error\/"},"modified":"2025-01-03T22:30:51","modified_gmt":"2025-01-03T22:30:51","slug":"rigid-dynamics-forced-frictional-sliding-contact-error","status":"publish","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/rigid-dynamics-forced-frictional-sliding-contact-error\/","title":{"rendered":"Rigid dynamics forced frictional sliding contact error"},"content":{"rendered":"<p>&lt;p&gt;<strong>Hello,<\/strong>&lt;\/p&gt;&lt;p&gt;I am working on a thesis project involving contact modeling between a shaft and two annular ring surfaces (above and below the shaft). The analysis heavily relies on inertia forces. Below is the detailed modeling procedure and the issues I am encountering:&lt;\/p&gt;&lt;hr&gt;&lt;h3&gt;<strong>Modeling Procedure:<\/strong>&lt;\/h3&gt;&lt;h4&gt;<strong>1. Ring Setup:<\/strong>&lt;\/h4&gt;<\/p>\n<ul>\n<li>The ring is connected to the ground using a revolute joint, allowing rotation in the global <strong>Y<\/strong> direction.<\/li>\n<\/ul>\n<p>&lt;p&gt;<img decoding=\"async\" src=\"https:\/\/innovationspace.ansys.com\/forum\/wp-content\/uploads\/sites\/2\/2025\/01\/03-01-2025-1735939793-mceclip0.png\" \/>&lt;\/p&gt;&lt;h4&gt;<strong>2. Slider Setup:<\/strong>&lt;\/h4&gt;<\/p>\n<ul>\n<li>A slider is connected to the ring through a slot joint, allowing translational movement in the global <strong>Z<\/strong> (local <strong>X<\/strong>) direction relative to the ring.<\/li>\n<\/ul>\n<p>&lt;p&gt;<img decoding=\"async\" src=\"https:\/\/innovationspace.ansys.com\/forum\/wp-content\/uploads\/sites\/2\/2025\/01\/03-01-2025-1735939959-mceclip1.png\" \/>&lt;\/p&gt;&lt;p&gt;&nbsp;&lt;\/p&gt;<\/p>\n<ul>\n<li>To limit relative rotation between the ring and the slider in the local&nbsp;<strong>Y<\/strong> direction of the slider, a frictionless contact with a restitution factor of 0.1 is defined between the slider and the ring.<\/li>\n<\/ul>\n<p>&lt;p&gt;<img decoding=\"async\" src=\"https:\/\/innovationspace.ansys.com\/forum\/wp-content\/uploads\/sites\/2\/2025\/01\/03-01-2025-1735940132-mceclip2.png\" \/>&lt;\/p&gt;&lt;h4&gt;<strong>3. Shaft (Rotor)-Ring Contact:<\/strong>&lt;\/h4&gt;<\/p>\n<ul>\n<li>The rotor is connected to the slider via a revolute joint.<\/li>\n<\/ul>\n<p>&lt;p&gt;<img decoding=\"async\" src=\"https:\/\/innovationspace.ansys.com\/forum\/wp-content\/uploads\/sites\/2\/2025\/01\/03-01-2025-1735940310-mceclip3.png\" \/>&lt;\/p&gt;<\/p>\n<ul>\n<li>A forced frictional contact is defined between the rotor shaft and the ring within the small gap. This contact has a restitution factor of 0 or 0.01 and is critical because it provides the driving force for the shaft.<\/li>\n<\/ul>\n<p>&lt;p&gt;<img decoding=\"async\" src=\"https:\/\/innovationspace.ansys.com\/forum\/wp-content\/uploads\/sites\/2\/2025\/01\/03-01-2025-1735940446-mceclip4.png\" \/>&lt;\/p&gt;<\/p>\n<ul>\n<li>The required physics here is to generate rotational torque through friction between the shaft and the annular rings. This torque arises due to gyroscopic precession, where the rotor&#8217;s initial high angular momentum is affected by changes in the ring&#8217;s angular momentum.<\/li>\n<\/ul>\n<p>&lt;p&gt;mesh&lt;\/p&gt;&lt;p&gt;<img decoding=\"async\" src=\"https:\/\/innovationspace.ansys.com\/forum\/wp-content\/uploads\/sites\/2\/2025\/01\/03-01-2025-1735941021-mceclip6.png\" \/>&lt;\/p&gt;&lt;p&gt;<img decoding=\"async\" src=\"https:\/\/innovationspace.ansys.com\/forum\/wp-content\/uploads\/sites\/2\/2025\/01\/03-01-2025-1735940584-mceclip5.png\" \/>&lt;\/p&gt;<\/p>\n<ul>\n<li>It will work as a frictional gear<\/li>\n<\/ul>\n<p>&lt;p&gt;All the above image are actually a simplified model with small are to mesh and run fast but it is never able to complete the analysis&lt;\/p&gt;&lt;p&gt;The older version with large area and with coarse mesh worked well but still not able to run the analysis till end.&lt;\/p&gt;&lt;p&gt;Older version of the model&lt;\/p&gt;&lt;p&gt;<img decoding=\"async\" src=\"https:\/\/innovationspace.ansys.com\/forum\/wp-content\/uploads\/sites\/2\/2025\/01\/03-01-2025-1735941146-mceclip7.png\" \/>&lt;\/p&gt;&lt;p&gt;Mesh&lt;\/p&gt;&lt;p&gt;<img decoding=\"async\" src=\"https:\/\/innovationspace.ansys.com\/forum\/wp-content\/uploads\/sites\/2\/2025\/01\/03-01-2025-1735941237-mceclip8.png\" \/>&lt;\/p&gt;&lt;p&gt;&nbsp;&lt;\/p&gt;&lt;h4&gt;<strong>4. Motion Inputs:<\/strong>&lt;\/h4&gt;<\/p>\n<ul>\n<li>An initial angular velocity is applied to the rotor through the revolute joint between the slider and the rotor.<\/li>\n<\/ul>\n<p>&lt;p&gt;<img decoding=\"async\" src=\"https:\/\/innovationspace.ansys.com\/forum\/wp-content\/uploads\/sites\/2\/2025\/01\/03-01-2025-1735941404-mceclip10.png\" \/>&lt;\/p&gt;<\/p>\n<ul>\n<li>A sinusoidal rotational motion is applied to the ring via the revolute joint.<\/li>\n<\/ul>\n<p>&lt;p&gt;<img decoding=\"async\" src=\"https:\/\/innovationspace.ansys.com\/forum\/wp-content\/uploads\/sites\/2\/2025\/01\/03-01-2025-1735941452-mceclip11.png\" \/>&lt;\/p&gt;&lt;hr&gt;&lt;h3&gt;<strong>Problem Description:<\/strong>&lt;\/h3&gt;<\/p>\n<ul>\n<li>The analysis runs successfully for lower angular velocities of rotor&nbsp; (e.g., 1200 RPM).<\/li>\n<li>However, when increasing the angular velocity of rotor to 4000 RPM or higher, the simulation only runs for a short duration (e.g., 0.017 s, 0.3 s, or 0.2 s) before terminating with errors.<\/li>\n<\/ul>\n<p>&lt;hr&gt;&lt;h3&gt;<strong>Errors Encountered:<\/strong>&lt;\/h3&gt;<\/p>\n<ol>\n<li>&lt;span style=&#8221;font-size: 14pt;&#8221;&gt;State inconsistency, no relevant contact point for an active\/impacting contact pair. Try reducing the time step&lt;\/span&gt;<\/li>\n<\/ol>\n<p>&lt;p&gt;&lt;span style=&#8221;font-size: 14pt;&#8221;&gt;<img decoding=\"async\" src=\"https:\/\/innovationspace.ansys.com\/forum\/wp-content\/uploads\/sites\/2\/2025\/01\/03-01-2025-1735941622-mceclip12.png\" \/>&lt;\/span&gt;&lt;\/p&gt;&lt;div id=&#8221;paraDiv&#8221; class=&#8221;text-color-primary&#8221; style=&#8221;display: inline;&#8221;&gt;&lt;p id=&#8221;paragraphData&#8221; class=&#8221; paragraphText text-color-primary&#8221; style=&#8221;font-size: 12px; display: inline; padding-left: 40px;&#8221;&gt;&lt;span style=&#8221;font-size: 14pt;&#8221;&gt;2. Inconsistency Inactive Penetrated&lt;\/span&gt;&lt;\/p&gt;&lt;p class=&#8221; paragraphText text-color-primary&#8221; style=&#8221;font-size: 12px; display: inline; padding-left: 40px;&#8221;&gt;&nbsp;&lt;\/p&gt;&lt;p class=&#8221; paragraphText text-color-primary&#8221; style=&#8221;font-size: 12px; display: inline; padding-left: 40px;&#8221;&gt;&lt;span style=&#8221;font-size: 14pt;&#8221;&gt;<img decoding=\"async\" src=\"https:\/\/innovationspace.ansys.com\/forum\/wp-content\/uploads\/sites\/2\/2025\/01\/03-01-2025-1735942087-mceclip13.png\" \/>&lt;\/span&gt;&lt;\/p&gt;&lt;\/div&gt;<\/p>\n<ol>\n<li>&lt;div id=&#8221;paraDiv&#8221; class=&#8221;text-color-primary&#8221; style=&#8221;display: inline;&#8221;&gt;&lt;p style=&#8221;font-size: 12px; display: inline;&#8221;&gt;&lt;span style=&#8221;font-size: 14pt;&#8221;&gt;This is the only simmulation that ran lomg enough to see required displacement.&lt;\/span&gt;&lt;\/p&gt;&lt;\/div&gt;<\/li>\n<\/ol>\n<p>&lt;hr&gt;&lt;h3&gt;<strong>Efforts Taken:<\/strong>&lt;\/h3&gt;<\/p>\n<ul>\n<li>I have experimented with various mesh sizes, frictional cofficents, convex and inlined contact surfaces, different cofficent of restrituions, joints and solver settings\/configurations.<\/li>\n<li>I tried with a minimum time step of 1e-15s and still didnt get it done. and in some iterations the analysis is not taking the time step above 1e-7s even if a gave 1e-15s<\/li>\n<li>Despite multiple iterations, I have been unable to achieve convergence or extend the simulation duration for higher angular velocities.<\/li>\n<\/ul>\n<p>&lt;hr&gt;&lt;h3&gt;<strong>Request for Help:<\/strong>&lt;\/h3&gt;&lt;p&gt;I would greatly appreciate any guidance on the following points:&lt;\/p&gt;<\/p>\n<ol>\n<li>How can I improve the stability of the simulation for high angular velocities (4000 RPM and above)?<\/li>\n<li>Are there specific solver settings, meshing strategies, or contact modeling techniques that could help resolve these issues?<\/li>\n<li>Could the errors be related to the restitution or frictional contact settings, and if so, what adjustments would you recommend?<\/li>\n<li>Does the joint radius and length inputs will effect the analysis?<\/li>\n<\/ol>\n<p>&lt;p&gt;This analysis is critical to my thesis project, and any suggestions or insights would be immensely helpful. Thank you!&lt;\/p&gt;<\/p>\n","protected":false},"template":"","class_list":["post-403453","topic","type-topic","status-publish","hentry","topic-tag-contact","topic-tag-contact-behavior-1","topic-tag-rigid-body-dynamics"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_forum_id":["27791"],"_bbp_topic_id":["403453"],"_bbp_subscription":["498104","20905","12219"],"_bbp_author_ip":["103.158.43.18"],"_bbp_last_reply_id":["407769"],"_bbp_last_active_id":["407769"],"_bbp_last_active_time":["2025-01-30 15:21:57"],"_bbp_reply_count":["13"],"_bbp_reply_count_hidden":["0"],"_bbp_voice_count":["3"],"_bbp_engagement":["498104","20905","12219"],"_btv_view_count":["510"],"_bbp_topic_status":["unanswered"],"_bbp_notification_enabled":["498104"],"_edit_lock":["1735969609:498104"]},"test":"oe23m012smail-iitm-ac-in"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/403453","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\/403453\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=403453"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}