eigenvalue

I want to use Intel Math Kernel Library (MKL) to calculate the bifurcation loads and modes in my custom FE program. MKL has many algorithms and I want to use the most efficient one.

Basically, I need to find a few eigenvalues lambda_i and eigenvectors u_i for the problem

KG * u = lambda * KS * u

where KG is the stiffness matrix and KS is the geometric stiffness matrix, also called stress-displacement matrix.

Is KG supposed to be positive definite?

Bifurcation Analysis in Abaqus

Submitted by AliADawood on Wed, 08/21/2013 - 17:36

Hello Everyone,

Im relatively new to Abaqus and I have to carry out a bifurcation analysis of a pipe. Once that is done I need to add the imperfection wavelength and amplitude calculated to the pipe and carry out further simulations.

Ive been trying very hard to get a direction as to where to start with it. Can anyone please help me with it? I know that you need to carry out a buckle analysis that will give you a wrinkle pattern on the pipe. This inturn will add up to the bifurcation scheme that you get.

Wanted: Fast FEA Solvers...

Submitted by Ajit R. Jadhav on Fri, 05/14/2010 - 14:18

Summary:

I am thinking of informally conducting a specific case-study concerning the FEA solvers. The reference problem is a very simple but typical problem from stress analysis, leading of course to the linear systems: Ax = b and Ax = Lx.

I seek advice as to what software libraries currently available in the public domain would be best to use---the ones that would be fastest in terms of execution time for the reference problem.