search

Yeuyo / GNLSFEA

Geometrically-Nonlinear Shell Finite Element Analysis
27 stars 16 forks source link

Program Notes #2

Open NNNOTNERD opened 2 years ago

NNNOTNERD commented 2 years ago

Dear Yeuyo

Thanks for you great work on nonlinear FEA. But I can understand it vary well. For example: nDoF=nodes5;
neDoF=(95)^2;
What is the function of parameter neDoF？And many parameters，I can't understand it very well. So,Could you please give a more detailed manual about Program?

Thanks a lot.

Best regards yang

Yeuyo commented 1 year ago

Dear Yang,

Sorry for the late reply.

nDoF is the number of Degree of Freedom for each element. In this case, we have 5 degrees of freedom at each node (displacement along x-axis, displacement along y-axis, displacement along z-axis, rotation about local x-axis and rotation about local y-axis [refer to page 90 of the Thesis for more details]). This result in the nDoF = nodes * 5.

neDOF = (9 5) ^ 2 is the number of element's Degree of Freedom, in this case, we have 9 nodes per element, that's where the 9 comes from. I wanted to make use of MATLAB's sparse matrix function, so I converted my Stiffness Matrix into a huge diagonal sparse matrix, this resulting in needing a Sparse matrix of n^2 of size (for example, if I want to store relationship values between 2 variables in a matrix that only store values along its diagonals, I would need a matrix of n ^ 2 rows and columns [to store values from a 2 2 matrix, which has 4 values, a 4 * 4 matrix is required]).

More information could be found in the my thesis I linked earlier. Please do let me know if there are specific things you are unclear about.

Regards, Yeuyo