How do I solve for displacements after getting my stiffness matrix [K]?
How do I solve for displacements after getting my stiffness matrix [K]?
(OP)
I've written a Matlab program that creates a global stiffness matrix for a group of Q8 elements.
I have a force vector, now I'm trying to apply boundary conditions and solve for the displacements. The problem I've run into, is whether I eliminate rows and columns correlated to Dof's that equal 0 or if I
use lagrangians I end up with a singular K matrix that can't solve the system using backdivide.
Whats the best way to implement boundary conditions and solve for the displacements after obtaining global stiffness?
I have a force vector, now I'm trying to apply boundary conditions and solve for the displacements. The problem I've run into, is whether I eliminate rows and columns correlated to Dof's that equal 0 or if I
use lagrangians I end up with a singular K matrix that can't solve the system using backdivide.
Whats the best way to implement boundary conditions and solve for the displacements after obtaining global stiffness?
RE: How do I solve for displacements after getting my stiffness matrix [K]?
RE: How do I solve for displacements after getting my stiffness matrix [K]?
Right now I'm running the program on a single Q8 element. Each node has two in plane translational Dof's. I've constrained the bottom three nodes in both directions, and applied a load on the top right corner of the Q8, acting laterally. I feel like the model would be constrained, could you offer any insight into how to constrain it properly?
RE: How do I solve for displacements after getting my stiffness matrix [K]?
Was this element's formulation taken from some Matlab library or defined from scratch by you ?
There are two books that can be particularly useful for you:
- "Introduction to Finite Element Analysis Using Matlab and Abaqus" A. Khennane
- "The Finite Element Method Using Matlab" Y.W. Kwon, H. Bang
They discuss plane stress/strain elements as well (especially the first one may help).
RE: How do I solve for displacements after getting my stiffness matrix [K]?
Thanks for recomending those books, had one of them on my wishlist already.