{"id":34953,"date":"2019-04-25T18:29:43","date_gmt":"2019-04-25T18:29:43","guid":{"rendered":"\/forum\/forums\/topic\/fixing-the-y-rotation-rigid-body-dynamics\/"},"modified":"2019-04-25T18:29:43","modified_gmt":"2019-04-25T18:29:43","slug":"fixing-the-y-rotation-rigid-body-dynamics","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/fixing-the-y-rotation-rigid-body-dynamics\/","title":{"rendered":"Fixing the Y-Rotation – Rigid Body Dynamics"},"content":{"rendered":"

Hello,<\/p>\n

I am trying to do a Rigid Body Dynamic analysis of a manipulator arm with two triangular shaped plates, a spherical joint connector and springs in place. I want to find the forces experienced by the spherical joint, springs as well as the rotation of the spherical joint wrt the x and z axis.
I am applying a force of 30lbf on the top plate. There is gravity effect and the lower cylindrical segment is fixed. The materials used are ABS+PC plastic. I have not used any contacts. Just the spherical joint, fixed joint (Body to ground) and two other fixed joints(Body-Body) which connect the spherical joint connectors’ cylindrical part to the top plate. <\/p>\n

When I apply the force on one of the 3 smaller hemispherical faces (where springs are connected; Ref Fig 1), I get a solution without any interference of the springs\/spherical joint into the body. Although there is quite a bit of rotation about the Y axis which I want to completely restrict. <\/p>\n

Case -1 
\"Fig-1\"<\/p>\n

                                                                         Fig-1<\/p>\n

Final position:
\"Final<\/p>\n

When I apply the same force on the center of the top plate (near the spherical joint support location; Ref Fig 3), then the rotation about Y gets out of hand and the springs as well as the spherical joint go through the surfaces of the lower plate. <\/p>\n

\"Fig-3\"<\/p>\n

Final position case-2<\/p>\n

\"Final<\/p>\n

I want to :
1) Restrict the rotation about Y axis completely. Spherical joints don’t provide any option for restricting one DOF or of applying stops. I don’t know how else to apply a constrain to prevent rotation about Y.<\/p>\n

2) Restrict the springs and spherical joint from going through surfaces. Adding contacts always gives me an error and prevents problem from solving. I have been told to use only joints in Rigid body Dynamics. <\/p>\n

Any advice would be highly appreciated. I have searched extensively online and haven’t found anything yet. I have just recently started working on Rigid Body Dynamics in ANSYS (1 month), so I am not sure if I am making any silly mistakes that is causing all this. Would love to know your inputs on this. <\/p>\n

Thanks in advance. <\/p>\n","protected":false},"template":"","class_list":["post-34953","topic","type-topic","status-closed","hentry"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_old_topic_id":["7125"],"_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","0"],"_btv_view_count":["2812"],"_bbp_topic_status":["unanswered"],"_bbp_status":["publish"],"_bbp_topic_id":["34953"],"_bbp_forum_id":["27791"],"_bbp_engagement":["240","164848"],"_bbp_voice_count":["2"],"_bbp_reply_count":["3"],"_bbp_last_reply_id":["83912"],"_bbp_last_active_id":["83912"],"_bbp_last_active_time":["2019-04-26 17:58:03"]},"test":"yanivvk"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/34953","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\/34953\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=34953"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}