Element Stiffness Matrix

Last revised: Thursday, January 29, 2026 at 02:58 PM

The element formulation accounts for Dx, Dy and Dz of the local coordinate system.  The element stiffness matrix is based on isoparametric compatible or incompatible formulation [Ref 1, 2, 3].  Therefore, the stiffness matrix is of size 24 by 24.  Full two by two numerical integration is used to calculate the stiffness matrix.