{"id":458200,"date":"2026-05-15T02:10:55","date_gmt":"2026-05-15T02:10:55","guid":{"rendered":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/how-to-mimic-1d-site-response-analysis-in-2d-without-using-constrained_node_set\/"},"modified":"2026-05-15T02:10:55","modified_gmt":"2026-05-15T02:10:55","slug":"how-to-mimic-1d-site-response-analysis-in-2d-without-using-constrained_node_set","status":"publish","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/how-to-mimic-1d-site-response-analysis-in-2d-without-using-constrained_node_set\/","title":{"rendered":"How to mimic 1D site response analysis in 2D without using *CONSTRAINED_NODE_SET"},"content":{"rendered":"<p>&lt;p data-path-to-node=&#8221;4&#8243;&gt;Hi everyone,&lt;\/p&gt;&lt;p data-path-to-node=&#8221;5&#8243;&gt;I&rsquo;m running a 2D plane-strain site response analysis of a soil basin. To handle the side boundaries, I meshed 1D columns (local periodic boundaries) on the far left and right edges, and connected them to the main basin using dashpots.&lt;\/p&gt;&lt;p data-path-to-node=&#8221;5&#8243;&gt;During gravity initialization (Dynamic Relaxation), I use a &lt;code data-path-to-node=&#8221;7&#8243; data-index-in-node=&#8221;73&#8243;&gt;*BOUNDARY_SPC_SET_BIRTH_DEATH<\/code> to lock the basin edges horizontally so a gap doesn&#8217;t form. DR converges perfectly, and the mesh sits completely flush.&lt;\/p&gt;&lt;p data-path-to-node=&#8221;5&#8243;&gt;I am also applying&nbsp;&lt;span class=&#8221;math-inline&#8221; data-math=&#8221;\\sigma_{xx}&#8221; data-index-in-node=&#8221;21&#8243;&gt;sigma_xx &lt;\/span&gt;and &lt;span class=&#8221;math-inline&#8221; data-math=&#8221;\\tau_{zx}&#8221; data-index-in-node=&#8221;37&#8243;&gt;tau_zx&nbsp; form elout to the inner sides of main model which are on the boundary between far side columns and main domain.&nbsp;&lt;br&gt;&lt;br&gt;I am still not capturing uniform free field response on the surface.&nbsp;&lt;\/span&gt;&lt;\/p&gt;&lt;p data-path-to-node=&#8221;5&#8243;&gt;&lt;span class=&#8221;math-inline&#8221; data-math=&#8221;\\tau_{zx}&#8221; data-index-in-node=&#8221;37&#8243;&gt;How can I mimic the free field case just like a 1D site response analysis? (I cant want to use *CONSTRAINED_NODE_SET as I will non-flat non-uniform geometry affects in future)&nbsp;&lt;\/span&gt;&lt;\/p&gt;&lt;p data-path-to-node=&#8221;5&#8243;&gt;&lt;span class=&#8221;math-inline&#8221; data-math=&#8221;\\tau_{zx}&#8221; data-index-in-node=&#8221;37&#8243;&gt;Best,&lt;\/span&gt;&lt;\/p&gt;&lt;p data-path-to-node=&#8221;5&#8243;&gt;&lt;span class=&#8221;math-inline&#8221; data-math=&#8221;\\tau_{zx}&#8221; data-index-in-node=&#8221;37&#8243;&gt;Muhsin&lt;\/span&gt;&lt;\/p&gt;&lt;p data-path-to-node=&#8221;5&#8243;&gt;&nbsp;&lt;\/p&gt;<\/p>\n","protected":false},"template":"","class_list":["post-458200","topic","type-topic","status-publish","hentry"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_forum_id":["27814"],"_bbp_topic_id":["458200"],"_bbp_author_ip":["134.197.0.17"],"_bbp_last_reply_id":["0"],"_bbp_last_active_id":["458200"],"_bbp_last_active_time":["2026-05-15 02:10:55"],"_bbp_reply_count":["0"],"_bbp_reply_count_hidden":["0"],"_bbp_voice_count":["1"],"_bbp_engagement":["687726"],"_btv_view_count":["80"],"_bbp_topic_status":["unanswered"]},"test":"muhsinacarrgmail-com"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/458200","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\/458200\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=458200"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}