Here is a video tutorial which explains your questions in detail :

https://youtu.be/-8G1Eh1B0CU

0:40 - 13:00

1(what this mean),0.9(what this mean).

First number is number of the eigenmode

Second number is the scaling factor of above-mentioned eigenmode

I recommend this book:

http://homepage.tudelft.nl/p3r3s/MSc_projects/reportTimChen.pdf

Thanks a lot, Ronald Heinz Norbert Wagner sir,

In your video for cylindrical shell, you appled imperfection, I am interested in beams sir for which the imperfection is categorized into various properties, but how it was done was not clear to me sir.

You do it for the beam the same way as for the cylinder.

How do you model the beam, with beam elements or shell elements, solid elements...?

What do you not understand specifically?

With thanks,

I am modeling a beam with shell element sir.

The thing I need to know is;

*Is there any other way to skip the Imperfection effect, if we put 1 Does it take no imperfection in it?

*For cylinders you consider thickness imperfection, but for beams, many journals use Length, breadth, thickness, etc...How to find the perfect one

*What is the sole importance of imperfection?

Once again, Thanks for your time to a budding student sir.

Dear Giri Prasad Gurunathan why do you want to skip the imperfection effect? If you want to skip it in Abaqus you should not define it. In Abaqus you have to define the corresponding eigenvalue and the amplitude of the imperfection. For beams the amplitude of the initial imperfection is usually L/1000 if we run geometrically and materially nonlinear analysis with imperfections (also known as GMNIA). In the Eurocode 1993-1-1 standard you can find some recommended value for the amplitude of the initial imperfections if you do not want to run GMNIA.

In the corresponding literature you can find that what is the sole importance of the initial imperfection:

https://www.sciencedirect.com/topics/engineering/initial-geometric-imperfection

Thanks you Gabor.