Hi all, In Modules/Numerics/FEM/src/itkFEMElementBase.cxx and in function GetStiffnessMatrix() the element stiffness matrix (Ke) is calculated. I believe that when the Linear tetrahedron element is used (class Element3DC0LinearTetrahedronStrain) then stiffness matrix equals to :
Ke = *(1/6)* * detJ * w * B.transpose() * D * B and not with Ke = detJ * w * B.transpose() * D * B In case of the hexahedron element the infinitesimal volume dV that we want to integrate the entries of the stiffness matrix equals to : dV = dx*dy*dz = det(J) * dr*ds*dt However in case of thetrahedron is: dV = dx*dy*dz = (1/6) * det(J) * dr*ds*dt where det(J) is the determinant of the Jacobian matrix. Regards Fotis Drakopoulos
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