Hi,
I have written a code for analysis of curved shell structures using Ahmed/Irons/Zienkiewicz degenerated shell element. Now I would like to connect it to a more complex structure with beams and trusses. Degenerated shell elements have 5 degrees of freedom in node (3 translations wrt global...
Hello,
I would like to perform a buckling analysis of a thin concrete doubly curved shell structure (architectural / structural). I am writing my own code and as a shell element I am using a combination of a plane stress triangle (for membrane forces) and DKT triangle (for plate part of the...
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 * (...
Hi all,
I am looking for some textbook, lecture notes or online resource about how to efficiently organize FEM code (from the programming point of view).
I have already wrote some small FEM codes for specific problems, but this time I need to make it bigger (coupling different element types -...
Hi friends,
I am trying to calculate 8-node brick element load vecotr. Top face consist from points 1-2-3-4, bottom face from points 5-6-7-8.
When I am calculating self weight (body forces) I am using 8-node brick shape functions (8 shape functions).
When I have a surface load perpendicular to...
Hi all,
I am trying to follow Ansys theory manual for Newton Raphson analysis of geometrically nonlinear problems.
There is:
Kt * dU = (F_int - F_ext) (1)
u = u + dU (2)
Kt = Ke + Kg
dU = incrmenet of deformations (this is what we are looking for)
F_ext = vector of applied...
Hi everybody,
I am trying to write my own code for geometric nonlinear analysis of mixed cable, truss and beam structure. I am trying to follow Newton-Raphson procedure (non incremental) from Ansys theory manual, but I cant achieve convergence. Here is my flow:
==== Linear analysis ====
u(1)...
