Detailed calculation of the shell using indexes

How to use indexes to calculate the shell

In the future, we will assume that the shell is supported by ribs in two directions.

 All parameters related to the longitudinal ribs are marked with the lower index “1”, and to the transverse ribs – the lower index “2”. It is assumed that the ribs of both directions are located regularly and that it is permissible to “smear” the material of the ribs. Conditions under which the consideration of the ribbed membrane as structurally orthotropic (the frequency of the ribs) is permissible, are not considered here, but it is believed that these are survived.