“…One may distinguish between element formulations, which model a reference surface of the shell structure, see e.g. [1,2,3,4,5,6], and solid shell elements which model the top and bottom surfaces of structures, see e. g. [7,8,9,10,11,12]. Some of these element formulations are restricted to shallow shell structures, [5,6], where the initial shell curvature is assumed to be small.…”