{"id":389420,"date":"2024-10-14T03:03:26","date_gmt":"2024-10-14T03:03:26","guid":{"rendered":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/is-ansys-apdls-geometric-stiffness-matrix-for-solid-elements-wrong-2\/"},"modified":"2024-10-14T03:03:26","modified_gmt":"2024-10-14T03:03:26","slug":"is-ansys-apdls-geometric-stiffness-matrix-for-solid-elements-wrong-2","status":"publish","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/is-ansys-apdls-geometric-stiffness-matrix-for-solid-elements-wrong-2\/","title":{"rendered":"Is ANSYS APDL&#8217;s geometric stiffness matrix for solid elements wrong?"},"content":{"rendered":"<p>&lt;p&gt;I derived Cook&#8217;s theory and also rewrote Borst&#8217;s theory. When they introduced the calculation formula for the geometric stiffness matrix of solid elements, the matrix had zero elements. Why is the geometric stiffness matrix output by ANSYS APDL entirely composed of non-zero elements? Was the calculation incorrect?&lt;\/p&gt;&lt;p&gt;<img decoding=\"async\" src=\"https:\/\/innovationspace.ansys.com\/forum\/wp-content\/uploads\/sites\/2\/2024\/10\/14-10-2024-1728875003-mceclip1.png\" \/>&lt;\/p&gt;&lt;p&gt;<img decoding=\"async\" src=\"https:\/\/innovationspace.ansys.com\/forum\/wp-content\/uploads\/sites\/2\/2024\/10\/14-10-2024-1728874963-mceclip0.png\" \/>&lt;\/p&gt;&lt;p&gt;&nbsp;&lt;\/p&gt;<\/p>\n","protected":false},"template":"","class_list":["post-389420","topic","type-topic","status-publish","hentry"],"aioseo_notices":[],"aioseo_head":"\n\t\t<!-- All in One SEO 4.9.10 - aioseo.com -->\n\t<meta name=\"description\" content=\"I derived Cook&#039;s theory and also rewrote Borst&#039;s theory. When they introduced the calculation formula for the geometric stiffness matrix of solid elements, the matrix had zero elements. Why is the geometric stiffness matrix output by ANSYS APDL entirely composed of non-zero elements? 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