I have understood the meaning of F11,F12, F22, V13, V23, M11, M22, etc but am still confused which one to use to check my shell forces. Please suggest some tutorial video if available
To use any of the mentioned by you elements in the analysis you must take into account the characteristics (mainly thickness) of the shell under consideration and, also, which type of internal stresses in the body of the shell you want to receive (flat or spatial).