Imperfection sensitive structures such as unstiffened or skin-dominant shell structures are commonly used for aeronautic and aerospace applications. Cylindrical shells are dominating satellite launcher structures and a reliable methodology to calculate their behavior in the early stages of design is fundamental to achieve optimum results. Launcher design requires fast and precise prediction of structural weight its weight distribution already in the early design phase, because in that phase different concepts of the whole launcher have to be evaluated in order to identify the optimal one. The prediction has to be precise, because less reliable ones might lead to basic changes, later in the detailed design phase, which might also influence the design of the whole system. Such changes in later design phase are extremely costly in terms and money; they definitely have to be avoided.