Hi friends,
I am looking for an advice. I am constructing tangent stiffness matrix of an arbitrary element for stability or nonlinear analysis. When I am transforming the stiffness matrix from local to global coordinate system, which approach is correct:
(1) K = Tt * Ke * T + Kg
(2) K = Tt * ( Ke + Kg ) * T
where
K = tangent stiffness matrix
Tt = transposed trasnformation matrix
T = transformation matrix
Ke = elastic stiffness matrix
Kg = geometric (initial stress) stiffness matrix
I have found both approaches in the literature (1) Bathe - Finite element procedures, (2) Bathe - Finite Element Procedures for Solids and Structures - Nonlinear Analysis - MIT Open Courseware - Lecture notes
I am confused, so many thanks for any advice.
I am looking for an advice. I am constructing tangent stiffness matrix of an arbitrary element for stability or nonlinear analysis. When I am transforming the stiffness matrix from local to global coordinate system, which approach is correct:
(1) K = Tt * Ke * T + Kg
(2) K = Tt * ( Ke + Kg ) * T
where
K = tangent stiffness matrix
Tt = transposed trasnformation matrix
T = transformation matrix
Ke = elastic stiffness matrix
Kg = geometric (initial stress) stiffness matrix
I have found both approaches in the literature (1) Bathe - Finite element procedures, (2) Bathe - Finite Element Procedures for Solids and Structures - Nonlinear Analysis - MIT Open Courseware - Lecture notes
I am confused, so many thanks for any advice.