Paul Thomas

6 Questions 10 Answers 0 Followers

Questions related from Paul Thomas

Python Scipy.sparse RuntimeError: Factor is exactly singular

Hello, I was trying to find the LU factorization for a sparse matrix(size 159990 by 159990). Following are the three lines in python i have used for the LU decomposition " from scipy.sparse import...

08 August 2017 8,587 1 View

How to find the eigenvectors within a specific eigenvalue range for a large sparse symmetric matrix (162000 by 162000)?

Hello, I would like to find all the eigenvectors within a specific eigenvalue range. The matrix i am dealing with is large sparse symmetric matrix with size 162000 by 162000. I am...

08 August 2017 7,723 3 View

How to efficiently calculate 160146 by 160146 matrix inverse in python?

Hello, My research is into structural dynamics and i am dealing with large symmetric sparse matrix calculation. Recently, i have to calculate the stiffness matrix (160146 by 160146) inverse with...

08 August 2017 7,642 6 View

How to convert a dense 12 by 12 stiffness matrix into standard beam element stiffness matrix format?

Hello, I have faced with a challenge to represent a dense 12 by 12 matrix into a standard beam element stiffness matrix format.The dense stiffness matrix represented by K have 72 elements. Whereas...

06 June 2017 8,798 4 View

Why the first 6 rigid body modes are not zero in a Free- Free analysis?

Hello, Recently i have done a MSC NASTRAN Free-Free analysis for a FEM consisting of only one beam element (See Figure:1 in attached excel sheet). I could not get the all eigenvalue roots of the...

05 May 2017 6,399 7 View

How to find beam properties like moment of inertia, polar moment of inertia, E, G, A from its 3D beam element stiffness matrix?

Hello, I have condensed a Finite element model from 8 nodes with 6 dof at each node into 2 nodes with 6 dof at each node using a static condensation method (or Guyan reduction). Now i would like...

04 April 2017 3,870 6 View