Ansys Employee

It depends on the pipe: a balloon only needs a low pressure to distort, not sure I'd fancy trying to blow up a steel bag!  There's almost certainly a stress/strain/bendy calculation in your course notes or on the Learning section here.

It's more usual to calculate or specify the pressure you have, do some sums (on paper/spreadsheet) to find out what won't distort and order the next tube thickness up from that.