choosing the right eigenvalues for buckling analysis
choosing the right eigenvalues for buckling analysis
(OP)
hello everyone...
I am running an eigenvalue buckling analysis from input file from abaqus documentation.
The outcome of the linear analysis is series of eigenvalues
and they will give me the magnitude of buckling load by simply multiplying with the applied load.
my problem is how i am going to know the right eigenvalue ? is it just taking the lowest value of eigenvalue or just choosing any value that will give me the closest answer to the numerical/theoretical one? if the answer is taking the lowest eigenvalue, why i am keep getting very low value of eigenvalues?
i believe there is nothing wrong with the input file from the abaqus documentation.
Thanks in advance
I am running an eigenvalue buckling analysis from input file from abaqus documentation.
The outcome of the linear analysis is series of eigenvalues
and they will give me the magnitude of buckling load by simply multiplying with the applied load.
my problem is how i am going to know the right eigenvalue ? is it just taking the lowest value of eigenvalue or just choosing any value that will give me the closest answer to the numerical/theoretical one? if the answer is taking the lowest eigenvalue, why i am keep getting very low value of eigenvalues?
i believe there is nothing wrong with the input file from the abaqus documentation.
Thanks in advance





RE: choosing the right eigenvalues for buckling analysis
2) plot the mode shape (deformed geometry) for each eigenvalue and see if they make sense - good way to find boundary condition, connection, meshing, etc problems
3) are you saying you cannot reproduce the results in the Abaqus manual?
RE: choosing the right eigenvalues for buckling analysis
yes..the lowest eigenvalues that I got are no where near the results. So assuming the input files in the ABAQUS is correct, I am just choosing the value which give the closest to the correct answer, that means not neccessarily the lowest one.Is it okay to do that?
I have running the input file several time without getting error messages but still got the same results.
What is the most probable mistakes? Is it because of the boundary conditions or something else?
RE: choosing the right eigenvalues for buckling analysis
What specific example problem are you running? Please describe the porblem in detail.
Are you comparing to a result given in the Abaqus manual or to a theoretical result from another source?
RE: choosing the right eigenvalues for buckling analysis
i am running eigenvalue buckling analysis for cylindrical shell
i am comparing both from the abaqus manual and the theoretical result...but what confusing me was the 'very small' value of eigenvalue obtained after i run the analysis thru the input file from abaqus manual
here's the link:
htt
Just go to 1.analysis test -> 1.2 buckling analysis -> 1.2.3 Buckling of a cylindrical shell under uniform axial pressure
RE: choosing the right eigenvalues for buckling analysis
RE: choosing the right eigenvalues for buckling analysis
EigenVECTORS are normalised !
RE: choosing the right eigenvalues for buckling analysis
RE: choosing the right eigenvalues for buckling analysis